II I I I

CLEAVER-BROOKS PACKAGED

WATERTUBE BOILERS

MODELS D, DL, and DLD

© Aqua-Chem. Inc .• 1993

Please direct purchase orders for replacement manuals to your local Cleaver-Brooks representative

Manual Part No. 750-302

Printed in U.S.A

WAKN/NG

DO NOT OPERATE, SERVICE, OR REPAIR THIS EQUIPMENT UNLESS YOU FULLY UNDERSTAND ALL APPLICABLE SECTIONS OF THIS MANUAL.

DO NOT ALLOW OTHERS TO OPERATE, SERVICE, OR REPAIR THIS EQUIPMENT UNLESS THEY FULLY UNDERSTAND ALL APPLICABLE SECTIONS OF THIS MANUAL.

FAILURE TO FOLLOW ALL APPLICABLE WARNINGS AND INSTRUCTIONS MAY RESULT IN SE­VERE PERSONAL INJURY OR DEATH.

TO: Owners, Operators and/or Maintenance Personnel

This operating manual presents information that will help to properly operate and care for the equipment. Study its contents carefully. The unit will provide good service and continued vperation if proper operating and maintenance instructions are followed. No attempt should be made to operate the unit until the principles of operation and all of the components are thoroughly understood. Failure to follow all applicable instructions and warning may result in severe personal injury or death.

It is the responsibility of the owner to train and advise not only his or her personnel, but the contractor's personnel who are servicing, repairing or operating the equipment, in all safety aspects.

Cleaver-Brooks equipment is designed and engineered to give long life and excellent service on the job. The electrical and mechanical devices supplied as part of the unit were chosen because of their know ability to perform; however, proper operating techniques and maintenance procedures must be followed at all times. Although these componesnts afford a high degree of protection and safety, operation of equipment is not to be considered free from all dangers and hazards inherent in handling and firing of fuel.

Any "automatic" features included in the design do not relieve the attendant of any responsibility. Such features merely free himlher of certain repetitive chores and give himlher more time tot devote to the proper upkeep of equipment.

It is solely the operator's responsibility to properly operate and maintain the equipment. No amount of written instructions can replace intelligent thinking and reasoning and this manual is not intended to relieve the operating personnel of the responsibility for pr0~ operation. On the other hand, a thorough understanding of this manual is required before attempting to operate, maintain, service, or repair this equipment.

Because of state, local, or other applicable codes, there are a variety of electric controls and safety devices which vary consider­ably from one boiler to another. This manual contains information designed to show how a basic boiler operates.

Operating controls will normally function for long periods of time and we have found that some operators become lax in their daily or monthly tesing, assuming that normal operation will continue indefinitely. Malfunctions of controls lead to uneconomical operation and damage and, in most cases, these conditions ca nbe traced directly to carelessness and deficiencies in testing and maintenance.

It is recommended that a boiler room log or record be maintained. Recording of daily, weekly, nonthly and yearly maintenance activities and recording of any unusual operation will serve as a valuable guide to any necessary investigation.

Most instances of major boiler damage are the result of operation with low water. We cannot emphasize too strongly the need for the operator to periodica:J!y checkhislher low water controls and to follow gOOd maintenance and testIng practices. Cross­connecting piping to low water devices must be internally inspected periodically to guard agamst any stoppages which could obstruct the free flow of water to the low water devices. Float bowls of these controls must be inspected frequently to check for the presence of foreign substances that would impede float ball movement

The waterside condition of the pressure vessel is of extreme importance. Waterside surfaces should be insp:o:cted frequently to check for the presence of any mud, sludge, scale or corrosion.

The services of a qualified water treating company or a water consultant to recommend the proper boiler water treating practices are essential.

The operation of this equipment by the owner and hislher operating personnel must comply with all requirements or regulations ofhislher insurance company and/or other authority having jurisdiction. In the event of any conflict or inconsistency between such requirements and the warnings or instructions contained herein, please contact Cleaver-Brooks before proceeding.

CONTENTS

Page CHAPTER 1 - GENERAL DESCRIPTION ....................................... 1-1

A. The Boiler ...................................................... 1-1 B. The Burner and Control System ................................. 1-1 C. Components and Accessories ..................................... 1-1 D. Installation ...................................................... 1-6 E. Hydrostatic Testing and Inspection ............................... 1-6 F. Boiling Out .................... , .................. , ............. 1-7 G. Feedwater System and Treatment ................................ 1-9

CHAPTER 2 - OPERATIONS AND PROCEDURES .............................. 2-1 A. Preparation to Initial Firing ..................................... 2-1 B. Filling the Boiler ................................................ 2-1 C. Initial Firing .................................................... 2-2 D. Routine Operation and Shutdown ................................ 2-2 E. Operating Procedures ............................................ 2-3

Feed Water Regulation and Control ............................ 2-3 Water Level Indicating System ................................. 2-3 Water Column ................................................. 2-4 Blowdown ..................................................... 2-5 Manual Blowdown ............................................. 2-5 Continuous Blowdown ......................................... 2-6 Soot Blowing .................................................. 2-6 Superhea ter ................................................... 2-7

CHAPTER 3 - MAINTENANCE ................................................. 3-1 A. General ......................................................... 3-1

Waterside Inspection ........................................... 3-1 Fireside Inspection ............................................. 3-2

B. Pressure Vessel Care and Repairs ................................ 3-3 C. Tube Cleaning ................................................... 3-3

Mechanical Tube Cleaning ..................................... 3-3 Chemical Cleaning ............................................. 3-5

D. Water Column ............................................... " .. 3-5 Probe Installation ............................................. 3-5 Gauge Glass or Prismatic Insert ............................... 3-5

E. Safety Valves .................................................... 3-5 F. Care and Protection of Idle Boilers .............................. 3-7

CHAPTER 4 - PARTS ORDERING INSTRUCTIONS AND PARTS LIST ........ .4-1

TO: Owners, Operators or Maintenance Personnel

This operating manual presents information that will help to properly operate and care for the equipment. Study its contents carefu lIy, The unit will provide good service and continued operation if proper operating and maintenance instructions are followed, No attempt should be made to operate the unit until the principles of operation and all of the components are thoroughly understood, Only trained and authorized personnel should be allowed to operate, adjust or repair this equipment.

Cleaver-Brooks products are designed and engineered to give long life and excellent service on the job, The electrical and mechanical devices supplied as part of the unit were chosen because of their known ability to perform: however, proper operating techniques and maintenance procedures must be followed at all times, Although these components afford a high degree of protection and safety, operation of equipment is not to be considered free from all dangers and hazards inherent in handling and firing of fuel.

Any "automatic" features included in the deSign do not relieve the attendant of any responsibility, Such features merely free him of certain repetitive chores and give him more time to devote to the proper upkeep of equipment.

It is solely the operator's responsibility to properly operate and maintain the equipment. No amount of written instructions can replace intelligent thinking and reasoning and this manual is not intended to relieve the operating personnel of the responsibility for proper operation,

Because of state, local or other applicable codes there are a variety of electrical controls and safety devices which vary considerably from one installation to another, This manual contains information designed to show how a standardly equ ipped bu rner operates,

Operating controls will normally function for long periods of time and we have found that some operators become lax in their daily or monthly testing assuming that normal operation will continue indefinitely, Malfunctions of controls leads to uneconomical operation and damage and in most cases these conditions can be traced directly to carelessness and deficiencies in testing and maintenance,

It is recommended that a boiler room log or record be maintained, Recording of daily, weekly, monthly and yearly maintenance activities and recording of any unusual operation will serve as a valuable gu ide to any necessary investigation,

Most instances of major boiler damage are the result of operation with low water, We cannot emphasize too strongly the need for the operator to periodically check his low water controls and to follow' good maintenance and testing practices, Cross connecting piping to low water devices must be internally inspected periodically to guard against any stoppages which coUld obstruct the free flow of water to the low water devices, Float bowls of these controls must be inspected frequently to check for the presence of foreign substances that wou Id impede the float ball movement.

The waterside condition of the pressure vessel is of extreme importance, Waterside surfaces should be inspected frequently to check for the presence of any mud, sludge, scale or corrosion,

It is customary to engage the services of a qualified water treating company or a water consultant to recommend the proper boiler water treating practices,

The operation of this equipment by the owner and his operating personnel must comply with all requirements or regulations of his insurance company and/or any other authority having jurisdiction, These legal requirements take precedence over anything contained herein,

Cleaver-Brooks Service Engineers, or Cleaver-Brooks authorized service representatives, present for start-up or service are present on Iy in an advisory capacity, The operation of the bu rner or boi ler is under the scope of work to be performed by the owner's operating personnel at the owner's risk, and under the owner's insurance protection, Recommendation for proper adjustments required to make the equipment perform can 'be made by these Service Engineers,

III

Chapt pr 1 - General Descript ion

CHAPTER

GENERAL DESCRIPTION

A. THE BOILER

B. THE BURNER AND CONTROL SYSTEM

C. COMPONENTS AND ACCESSORIES

D. INSTALLATION

E. HYDROSTATIC TESTING AND INSPECTION

F. BOILING OUT

G. FEEDWATER SYSTEM AND TREATMENT

A. THE BOILER

The Cleaver-Brooks Packaged Watertube Steam Boiler is a two drum, bent-tube, "D" type Boiler. The line consists of three Models; "D", "DL" and "DLD" which vary only in size, dimensions, and capacity. All models are covered by this manual.

The Boiler has a six-wall water cooled furnace. The inside and outside furnace walls, as well as the floor and roof, are constructed of tangent tubes. The front and rear walls are refractory faced and have water cooling tubes. Figure 1-1 shows typical construction.

The entire pressure vessel is covered with a double seal-welded insulated casing. The pressure vessel is mounted on a heavy structural steel skid type frame.

The steam (upper) drum has factory installed in­ternals and baffles to control water levels, reduce surging, and to reduce the quantity of moisture leaving the water level before it enters the final dryer unit. Figure 1-2 shows a cross section of typical drum internals.

The boiler is constructed in accordance with the ASME Power Boiler Code, and all applicable local laws, regulations and codes having juris­diction.

B. THE BURNER AND CONTROL SYSTEM

The boiler is standardly equipped with a Cleaver­Brooks Burner. or in some instances, a burner manufactured by others. An indIvidual manual is

provided for the -burner portion. The various safety and combustion controls are either covered in the burner manual or by separate instructions. All instructions and manuals applicable to the in­stallation should be studied prior to firing the boiler.

C. COMPONENTS AND ACCESSO RIES

This section describes some of the various com· ponents and accessories that comprise a boiler. Some are integral to the pressure vessel while others are devices that are necessary for nprmal and safe operation. The accessory described may be furnished with the boiler or it may be fur· nished separately by others. Some installations may not require a particular component or it may vary somewhat from the following basic descrip· tions. See Figure 1-4.

The operator must be familiar with the indio vidual functioning of all controls and components in order to understand the boiler's operation. The following brief descriptions provide a basic un· derstanding of the functions and relationships. The descriptions are limited to those components that affect the pressure vessel. The boiler 'and fuel system controls, along with other special items that might be provided. are covered elsewhere.

STEAM DRUM

The upper drum (steam drum) contains water level control baffling to assure tha t all steam re­leased from the generating tubes is released be·

1·1

Chapter I - General Description

FIGURE 1-1 TYPICAL TUBE ARRANGEMENT

1-2

Chapter 1 - General Description

STEAM OUTLET STEAM OUTLET

c A F E

A. Dry Pan Carton D. Feedwater Pipe B. Flow Control Baffles C. Dry Pan Drain

E. Chemical Feed Pipe F. Continuous Blowdown Pipe

FIGURE 1-2 DRUM INTERNALS AND SEPARATOR

STEAM OUTLET

A. Purifier and Dryer Carton B. Flow Control Baffles C .. Feedwater Pipe

STEAM OUTLET

A

E

D. Chemical Feed Pipe E. Continuous Blowdown Pipe F. Steam Chest

FIGURE 1-3 DRUM INTERNALS AND STEAM PURIFIERS

o c

o c

1-3

Chapter 1 - General Description

hind the baffles and not through the' water level. Other drum internals include steam separators or dryers to assure low moisture content steam.

The drum heads are fitted with 12" by 16" man­ways on each end. The internal feed pipe, chemi­cal feed pipe, and blowdown piping are attached to the drum heads.

Figures 1-2 and 1-3 show typical drum internals.

LOWER WATER DRUM

The lower water drum has a blow off connection on the underside near the rear head. Internally it has a blow off guide baffle installed to insure ef­fective blow off of the lower drum without distur­bance to the water circulation of the boiler.

The drum incorporates two 12" x 16" manways one at each end.

BLOW OFF VALVES

These are specially designed, manually operated, valves connected to the lower drum for the pur­pose of reducing the concentration of solids in the boiler or for draining purposes. Two valves are required .by the ASME Code. The valves' nor­mally furnished are of. the slow opening type.

CONTINUOUS BLOWDOWN CONNECTION

The continuous blowdown connection is normally located in the rear head of the upper drum with the pipe located slightly below the normal water level. Its purpose is to remove the concentrated boiler water from the boiler and thereby reduce the total solids concentration. A flow control valve, or one with a variable orifice, is used to closely control the percent of blowdown. A stop valve is furnished, while the blowdown valve may be either provided with the boiler or furnished by others.

CHEMICAL FEED CONNECTION

This connection in the upper drum is provided for the piping from a chemical feed pump and is the means of introducing supplementary water treat­ment chemicals. into. the boiler.

SOOT BLOWER

A boiler equipped with an oil fired burner has a soot blower installed for cleaning accumulations of soot from the convection bank tubes. Steam is the most commonly used cleaning medium although compressed air is als,o used.

The soot blower is normally located on the rear wall of the boiler although front wall locations are not uncommon. Larger sizes of boilers have two soot blowers - front and rear. Stop and drain valves are provided. A sight cap is provided.in the side casing to allow visual checking of soot blower nozzle alignment.

1-4

OBSERVATION PORT

These are located in the rear wall to provide a good clear view of the flame.

STEAM GAUGE

Indicates the internal pressure of the boiler.

FEEDWATER REGULATING VALVE AND GENERATOR

These items comprise a system that operates automatically to maintain a predetermined water level in the boiler. The generator is essentially a closed hydraulic system, connected by tubing to a bellows on the regulating valve, that is responsive to the boiler water level. Hydraulic pressure created within the generator forces the valve to open to various positions thus regulating the flow of water to maintain a constant level.

A single element system is standardly furnished although other systems may be used depending upon job requirements and specifications.

FEEDWATER BYPASS VALVE

A manually operated valve provided to initially fill the boiler or to bypass the regulating valve.

SAFETY VALVE

This is an automatic pressure relieving device and, as the name implies, is for the purpose of safely relieving the boiler of any excessive steam pressure. The size and number of valves - always two and often three - and their pressure setting are determined by job specifications and in ac­cordance with ASME Code requirements.

The discharge piping from the valves must also con'form to the ASME Code. See Figure 3-4. This piping is not furnished with the boiler.

If the boiler is equipped with a super-heater, a safety valve is also provided for the super-heater.

DRUM VENT VALVE

This manually operated valve is located on top of the steam drum. Its sole purpose is to vent air and entrained gases from the drum during start­up. It should also be opened when the boiler is being cooled down to prevent a vacuum from forming within the boiler.

WATER COLUMN

The water column is connected at its top to the steam space and at its bottom to the water space of the upper drum. A water gage, trycocks, and water level indicating devices are attached to or are part of the column.

The gage glass attached to the side of the column is used to visually indicate the boiler water level. This glass is one of the most important guides

GAGE GLASS COCKS (TRY-COCKS)

GAGE GLASS WATER COLUMN

SHUT-OFF COCKS~\.

WATER LEVEL GAGE GLASS";;~?

STEAM GAUGE ~ .•.•...••• : .. (J .•••••.•.•

y •. ~.

FEEDWATER INLET

STEAM DRUM

Chap! er I . General Descrip! ion

FEEDWATER REGULATOR GENERATOR

BLOWER MOTOR

PACKAGED BURNER ASSEMBLY

FEEDWATER REGULATING VALVE

FIGURE 1-4 TYPICAL WATERTUBE BOILER

available to the boiler operator. It should be kept clean and well· lighted for good visibility.

The gage glass is mounted between two valves which can be operated from floor level by means of an attached chain. The valve handles are linked together so that they may be opened or closed simultaneously. The valves can be quickly closed in the event of glass breakage. Guard rods are used to help protect the glass against ac­cidimtai damage. A flat reflex type glass is often used instead of a tubular glass.

Three trycocks are provided to check the accuracy of the gage glass leveL

The water column is fitted with probes, or elec­trodes, extending through the top flange down­wards into the steam and water spaces. These are wi"red into an electric relay system that will shut the burner down in the event of low water and also activate signal lights that indicate normal, low water or high water level conditions. The lat­ter two are generally connected to an audibl~ alarm system to alert the operator of a condition requiring immediate attention. -The operation of the system is explained later in this manuaL

An auxiliary low water cut-off control is often i!1-stalled to provide additional protection. This is generally of the float operated type and is wired

1-5

Chapt~er 1 - General Description

to interrupt the limit circuit and to shut off the fuel flow in the event water drops below the master low water cut-off point.

Drain valves are provided for the water column and for the gage glass. Piping to a safe point of discharge must be provided by others.

D. INSTALLATION

It is not within the scope of this manual to pro­vide installation instructions. These should follow the design specifications of the Architect, Engineer or Contractor. Good engineering prac­tices must prevail.

The boiler and related equipment must be in­stalled to conform to applicable codes. Compli­ance with codes will do much to insure a safe and dependable installation as the codes have been formulated to safeguard life and property. Fail­ure to comply with established regulations can necessitate costly modification or reconstruction.

The proper authorities should be consulted before installation preparation of a permanent nature is started, particularly in regard to boiler room structure, boiler venting, electrical service, fuel storage and piping and all other piping such as steam, water supply, blow-off, and drain lines.

All piping and valves must be installed in accord­ance with good engineering practices. Suitable strength piping and valves are to be used. All drains and discharge piping must be piped to a safe point of discharge.

The discharge piping from the safety valves and the method of connecting the piping is especially important. The piping should be arranged so that no "thrust from the weight or movement of the

.pipe cal! be· imparted to the valves. Refer to Figure 3-4 for a typical recommended method of piping.

Electrical wiring must conform to all electrical codes and proper size wiring used. The necessary switches, feed boxes, circuit breakers, etc. must be installed and operable.

All auxiliary equipment should be installed in ac­cordance with the recommendations of the respective manufacturers. Fan wheels, bearings, couplings, and shaft alignment should be checked and aligned. If the bases of auxiliary equipment are grouted, the alignment should be checked be­fore grouting or doweling and rechecked af­terwards.

Aisles, ladders, and stairs should be completed and accessible for the convenience and safety of the operating personnel. All obstructions such as scaffolding, refuse, tools, etc. must be removed from ducts, breechings, and platforms. Insulation of piping and duct work should be done in accord­ance with accepted practices.

Application should be made immediately for all permits required by law for boiler room con­struction and boiler installation. Although it is custom·ary for each Contractor involved to attend to the permit required for his phase of the work, it is advisable to make sure that no necessary per-mit is 9verlooked. The supply piping for a gas fired burner must not

be attached to or supported from the side casing The Cleaver-Brooks Boiler is constructed to con- walls. f~rm with the ASME Boiler Code and other codes

Occasionally a unit is repainted, especially in new known to apply. A Manufacturer's Data Report construction. When this is done, care must be covering the boiler construction, test and in- taken to see that paint is not applied to any spection is provided. moveable linkage, to the generator portion of the When the boiler is received, it should be given a feedwater regulator, valve stems and any other thorough inspection by a competent person to de- components where paint could interfere with nor-

~_~ __ ~ Jermine iL~nyJiamagebas occurred in transiLAU __ ~~..maLjlpeI"atiolL.. ___ n~~ __ __ ~ .. __ w ___ _

boxes and cartons should be uncrated carefully and checked against the packing slip. In case of damage or shortage, immediately ~ notify the carrier and file a claim.

The boiler should be inspected externally as well as internally. The bracing or shoring that may be used to protect the brick in the furnace area must be removed. The refractory should be inspected for evidence of loose or broken tile.

The following generalizations are intended for assistance and do not supplant any codes or con­struction criteria.

1-6

E. HYDROSTATIC TESTING AND INSPECTIO N

The boiler was hydrostatically tested in our shop and copies of the Manufacturers' Data Report, signed by the inspector witnessing and evidencing the test, have been forwarded to all jurisdictional bodies as well as to the boiler owner. To be sure that the pressure parts are still tight following shipment and installation, a hydrostatic test should be conducted as soon as possible after in­stallation. This test will generally be under the

superVISIOn and witnessed by an authorized in­spector who may represent either the state or municipality having jurisdiction or the insurance company covering the installation.

At the option of this inspector, this test may be at 1-1/2 times the design pressure of unit, or at a pressure slightly less than the setting of the low­est safety valve. The latter test will avoid the necessity of blanking or gagging safety valves, re­moving piping and plugging various pipe open-· ings, removin~ controls and gage glass, etc.-

Before starting a test, make sure that all foreign material, tools, personnel, etc., are removed from the boiler. Rinse out the boiler by playing high pressure water into the drums, tubes, nipples and headers. Depending upon the test pressure, be sure to blank off any part that is not designed to withstand the pressure to be developed. This will include water column, gage glass, feedwater regu­lators, pressure controls, etc. Safety valves, in this case, must be blanked or gagged.

All connections on the boiler should be closed with the exception of the vent, pressure gauge, and feed line through which pressure will be ap­plied.

When the boiler is ready for the test, it should be filled with water of a temperature not less than ambient and in no case less than 70°F. Care should be taken so that all air is vented while the boiler is being filled.

Fill the boiler until water overflows the vent. Close the vent.

Apply pressure slowly. The recommended rate of pressure increase is less than 50 psi per minute. Proper control must be maintained so that pressure does not exceed the desired setting. When this test pressure is reached, in!;lpection in accordance with the test objective can begin.

Upon completion of the test, release pressure slowly through a small drain valve. Then fully open vents and drains. Particular care must be given to make sure that parts not normally con­taining water during operation, such as the super­heater or circulating tubes above normal water level are drained free of water.

If temporary handhole or manhole gaskets were used for the test, they should be replaced with regular service gaskets before readying the unit for operation. Gaskets should never be reused.

Chapter 1 - General Description

Replace gage glass if necessary and make sure that gage cocks ~re open.

Remove all blanks or gags from safety valves.

Additional inspection at lhis time by the authorized inspector will determine whether the installation including piping arrangements, valves, gauges and controls and other equipment on the boiler meet Code and/or other juris­dictional requirements.

F. BOILING OUT

The internal surfaces of a new boiler will invar­iably contain deposits of oil, grease and pro­tective coatings inherent in manufacturing pro­cedures. It is important that these deposit~ be re­moved from the heating surfaces sinc~ this con­tamination will lower the heat transfer rate ·and possibly cause overheating of pressure vessel metal. These deposits can generally be removed by an alkaline boil out using readily available chemicals.

Before boil out procedures can begin, the boiler should be ready for firing and the operator must be familiar with the operation of the burner and follow instructions contained in the burner manual.

There are several boiling out procedures that may be followed and different materials are re­commended by different authorities. There are specially prepared trademarked chemicals avail­able. Some firms that manufacture and provide these are:

Betz Laboratories, Philadelphia, Pa. Dearborn Chemical Company, Chicago, Illinois Dow Chemical Company, Midland, Michigan Hall Laboratories, Pittsburgh, Pa. Nalco Chemical Company, Chicago, Illinois

The instructions and a"dvice provIded· by the manufacturer of the chemical should be followed.

Any oils or coating that may have drained into the drums should be wiped away with clean rags. Also remove any debris that might be present. One of the top manholes may be left open to aid in filling the boiler.

If the water column if fitted with a prismatic type gage glass, it is suggested that this be tempon~rily replaced with a round glass of adequate design pressure to avoid any aamage to the prismatic glass. In the event the boil out is not handi.ed by the feed water consultant or water treatment com-

1-7

Chapter 1 - General Description

pany, the following procedure is effective for cleaning a boiler.

The use of soda ash (sodium carbonate) and caustic soda (sodium hydroxide) at the rate of 3 to 5 pounds each per 1,000 lbs. water is suggested. A small amount of laundry detergent is often ad­ded as a wetting agent.

The chemicals should be dissolved prior to plac­ing them in the boiler. To make this solution,

. place warm water into a suitable container. Slowly introduce the dry chemical into the water, stirring at all times, untiI the chemical is com­pletely dissolved. Add the chemical slowly and in small amounts to prevent excessive heat and tur­bulence.

Use of a suitable face mask, goggles, rubber gloves and protective garments are strongly re­commended when handling or mixing caustic chemicals. Do not permit the dry material or the concentrated solution to come in contact with skin or clothing.

Fill the boiler with ambient temperature water to a point just below the manhole opening in the up­per drum. Add the chemicals in the solution through either the upper drum manhole, the up­per drum vent valve, or the chemical feed line. Secure the manhole if it was used for filling.

Fill the boiler with water to about 8" above nor­mal operating level. The normal level is at the center of the water gage glass. Exercise caution to prevent water spilling over into the superheater, if the boiler is equipped with one.

Open the steam drum vent valve. If the boiler is equipped with a superheater, open the super­heater drain and vent valves. Recheck the burner, feed water supply, gage glass, pressure gauge, and the position of all valves.

Start the burner and allow the boiler to warm up slowly. When steam vapor is noticed at the boiler vent, close the vent valve. The superheater inlet drain valve should also be closed, but the superheater outlet drain valve should be left open enough·· to permit continuous cooling of super­heater tubes. Allow boiler pressure to increase at a rate. not to exceed 100 psi per hour until pressure has reached half of normal operating pressure but not exceeding 150 psi. Keep the burner firing at a low rate to maintain this pressure for approx­imately 6 hours. During the pressure raising and boiling out period, keep water above the bottom of the gauge glass by adding water as required.

After completion of the boil out period, add water slowly until the gauge glass shows full. Blow down through the continuous blowdown line in the steam drum until the water falls to the level of the surface blowdown connection. From this

1-8

point, blow off with the bottom blowoff valves un­til water level falls to within two inches of the bottom of the gage glass. The water column and gage glass should also be blown down.

After each blow, refill the boiler to the top of the gage glass and allow the boiler to soak and boil for about fifteen minutes before the next blow cycle. Repeat this' cycle of blowdown operation for a minimum of six times or until a cool sample of the boiler water shows no oil.

If possible, maintain the cleaning concentration during the blowdown by using a chemical feed pump.

Pressure should be lowered somewhat during the blowing and refilling cycle, however, the pressure should not be allowed to fall below 50 psi.

At the completion of the boil out, shut off the bur­ner and allow boiler to cool. Open all vents and drain the boiler when the water temperature has fallen to 120°F. or less.

Inspect the drums and wipe out any sludge or scum that may be present. Then wash out boiler thoroughly with a high pressure hose, using water of approximately 70°F. temperature, or ambient. Use a hose on each individual tube including superheater and economizer tubes. If possible, this washing should be done from the bottom of the tube. The fireside of the boiler should be checked for any unusual conditions.

Upon completion of the wash down, inspect the in­ternal surfaces and if not clean, repeat the boil out.

Replace manhole covers and install new manhole gaskets. Replace the gage glass if necessary. Re­install the prismatic glass if boiler is so equipped.

Refill the boiler with clean, treated water. If not immediately being placed into service, fire the boiler until it is heated to at least 180°F. to drive off any dissolved gases which might otherwise corrode the metal.

1.) SYSTEM CONTAMINATION

Steam and water piping systems connected to the boiler may contain oil, grease or foreign matter. In new systems, the piping usually has an ac­cumulation of oil, grease and dirt. Old systems have an additional hazard in that the piping and receivers may be heavily limed and full of scale as the result of improper water treatment.

These impurities must be prevented from enter­ing the boiler. On a steam system the condensate should be wasted until tests show the elimination

of undesirable impurities. During the period that ,conjensate is wasted, attention must be given to the treatment of the water used as make up so that an accumulation of unwanted materials o~ corrosion of drums and tubes does not occur. Follow the advice of your water treating com­pany.

On a hot water system, chemical cleaning is generally necessary and the entire system should be drained after treatment. Consult water treat­ment companies for recommendations, cleaning compounds and application procedures.

If oil, di~t and scale accumulations are permitted to get into the boiler, it may be necessary to re­peat the boil out procedure. If this becomes necessary, the same procedure as outlined under boilout should be followed.

The waterside of the pressure vessel must be kept clean from grease, sludge and foreign material. Such deposits, if present, will not only shorten the life of the pressure vessel and interfere with effici­ent operation and functioning of control or safety devices, but might quite possibly cause un­necessary and expensive re-work, repairs and down time.

The pressure vessel waterside should be inspected on a periodic basis. This will reveal true internal conditions and serve as a check against condi­tions indicated by chemical analysis of the boiler water. Inspection should be made three months after initial starting and at regular 6, 9 or 12 month intervals thereafter. The frequency of fur­ther periodic inspections will depend upon the in­ternal conditions found.

If any unwanted conditions are observed your water consultant or water treating company should be contacted for recommendations.

Any sludge, mud or sediment found will have to be flushed out. The effectiveness of the blowdown practiced on steam boilers will be verified and scheduling or frequency of blowdown may have to be revised. The need for periodic draining or washout will also be indicated.

G. FEEDWATER SYSTEM AND TREATMENT

The subject of water supply and treatment is of great importance and it cannot adequately be covered in this manual. Maximum effectiveness and long trouble-free life of the pressure vessel are functions of properly treated water. The type and extent of water treatment is determined by the water supply. The services of a reliable boiler_

Chapter 1 . General Description

water treatment specialist or company should be engaged to a-nalyze the water and prescribe treat­ment. Their recommendations should be followed rigidly to prevent the presence of unwanted solids and corrosive gases. Failure to do so will result in ever decreasing boiler efficiency as well as shor­tened useful life.

Objectives of water treatment in general are:

a. Prevention of hard scale deposits or soft sludge type deposits, which impair the rate of heat transfer and can lead to overheated metal and costly down time and repairs.

b. Elimination of corrosive gases, in supply or boiler water.

c.. Prevention of intercrystalline cracking or caustic embrittleihent of boiler metal.

d. Prevention of carryover and foaming.

The accomplishment of these objectives generally require treatment before and after introduction of water into the boiler.

The selection of pre-treatment processes depends upon water source, chemical characteristics, amount of make-up water needed, plant opera­ting practices, etc. These treating methods in­clude filtering, softening, demineralizing, de­aerating and preheating.

After treatment involves the addition of chemi­cals to the boiler water. This after treatment is required to compensate for any variations in the pre-treatment and pre-boiler system and to assure the ultimate protection of the boiler. Be­cause of the variables involved, no one "boiler compound" can be considered a cure-all, nor is it advisable to experiment with home-made treat­ing methods. Sound recommendations and their employment should be augmented by periodic analysis of the raw water, boiler water and con­densate.

The internal or waterside surfaces of the pressure vessel should be inspected with sufficient fre­quency to determine the presence of any contami­nation, accumulations of foreign matter, corro­sion, and/or pitting. If these conditions are de­tected, the water consultant or feedwater treat­ment company should be consulted for advice on corrective action.

It is advisable to have a properly sized water meter installed in the raw water make-up line to accurately determine the amoun.t of raw water admitted to the boiler. This will aid the water treatment program in maintaining proper water­side conditions.

1-9

Chapter 2 . Operations and Procedures

CHAPTER 2

OPERA TIONS AND PROCEDURES A. PREPARATION TO INITIAL FIRING

B. FILLING THE BOILER

C. INITIAL FIRING

D. ROUTINE OPERATION AND SHUTDOWN

E. OPERATING PROCEDURES

A. PREPARATION TO INITIAL FIRING

The operator must be knowledgeable of the boiler, the burner and all controls and compo­nents and must be competent to operate this equipment. The operating conditions of all auxili· ary equipment and instrumentation that serves in the firing and feeding of the boiler should be for­mally checked out. Be sure that auxiliary equip­ment not supplied by Cleaver-Brooks is of ade­quate size and pressure to insure proper operation.

Check for proper voltage, fuses and overloads. Check rotation of all motors by momentarily clos­ing the motor starter or relay. Check the reset of all starters and controls having the manual reset feature. To the extent possible, all operating me­chanisms, valves, and the air damper and drive should be checked for evidence of operation and freedom from binding. Check the settings of all controls.

Verify fuel supply. Make certain that fuel pressure is sufficient and that gauges are indi­cating correctly. Properly set any adjustable limit on interlock controls. Pretest them for proper function at set points if feasible.

Before operating a boiler feed pump or an oil sup­ply pump, be sure that all valves in the line are open or properly positioned. Be certain that pump rotation is correct. If in doubt, remove coupling and check motor rotation. Some pumps can be severely damaged by even a momentarily reversed rotation. Also recheck coupling align­ment.

Check out the burner in accordance with pro­cedures given in the burner instruction manuaL

Safety valves should be inspected externally to see that they are free to operate and that their escape piping and drain piping are open to at­mosphere and free to expand without imposing strain upon the safety valve body. Make sure that any gags used during testing are removed. Ascer­tain that discharge piping from the safety valves and also from all blowdown and drain valves is piped to a SAFE point of discharge, so that emission of hot water or steam can not possibly cause injury to personnel or damage to property.

Prior to closing drum manholes, make certain that all internal fittings are in place and that no tools, gear or personnel remain inside. Make a final check of the fireside area to make sure no tools, construction gear, debris or personnel are present.

For safety's sake, make a final and complete pre­startup inspection especially checking fO.r any loose or incompleted piping or wiring or any other situation that might present a hazard.

B. FILLING THE BOILER

Check and close the manual blowoff valves, the continuous blowdown valves, the gage cocks and the water column and gage glass drain valves.

Open the upper drum vent valve, the water column shutoff valves, if any, the gage glass shutoff valves and the steam pressure gauge valve. Open the superheater vent and drain valves.

The boiler should be filled with properly treated feedwater using the bypass feed line. The water should be as close as possible to the metal tem­perature to prevent excessive temperature

2·1

Chapter 2 - Operations and Procedures

stresses that could cause tube leakage. 70°F. minimum water temperature is recommended unless ambient is considerably higher or lower. Fill to a level about two inches above the bottom of the .gage glass. Fill slowly and vent fully to prevent any pressure buildup from the flashing of warm water.

Blow down the water column and gage glass making sure that the water level returns to the proper level promptly. The gage cocks should also be operated to verify water level.

C. INITIAL FIRING

Start the burner following the instructions in the burner operating manual. Make sure that com­bustion is stable. Check and adjust the burner and its components as outlined in the burner manual.

The firing rate should be manually controlled and held in the low fire position until the boiler is properly warmed. Generally, the control circuit has a low fire control which will prevent the bur­ner from firing in other than the low fire position, until the boiler is sufficiently warm. This control is usually adjusted to cut in at approximately 50 psi.

The boiler should be brought up to temperature and pressure at a slow and carefully controlled rate. Conditions can vary, however, an accepted rate of water temperature rise for a steam boiler is approximately 80 to lOO°F. per hour.

On a superheater equipped boiler, it is imperative that the superheater vent valve be open while the steam valve is closed. The flow of steam through the superheater is essential for the protection of the tubes. Refer to the superheater section in this manual.

During this period of operation, carefully observe that all components function properly. Be pre­pared to shut the unit down should a lack of pro-

______p~:t' . ...Q.P~:t'atiQILh.eJ:.QJnJLeYjd ent. .. _Yis.u.allyob.seLY~ combustion conditions for proof that gauges, meters and other instrumentation are properly reporting conditions.

Close the drum vent when steam pressure is 10 to 25 psi. Open any drain or bypass valve in the steam piping, if provided. Refer to superheater section for information on its vent and drain valves.

Maintain the normal water level at all times. This is usually 4 inches below the steam drum center line. Maintain the water level by hand feeding or by blowing down as necessary. Too high a level will cause flooding and render the

2-2

separators ineffective, while too low a level will allow possible overheating of pressure parts. If the water level is not readily apparent, use the gage cocks and close inspection to determine the level. If the level is not visible, firing should be stopped and the reason for low level determined.

The feed water regulator should be cut in when operating pressure is obtained and the bypass feed line valves closed.

The operation of the safety valves should be veri­fied. This may involve raising the boiler pressure beyond normal operating setting to actually determine that valves open and close within the proper limits or it may require the hand lifting of the valve lever. The judgment and recommenda­tion of the authorized inspector should determine the method used.

When boiler pressure has increased to the desired point, the boiler can be cut into service according to good operating practice.

D. ROUTINE OPERATION AND SHUTDOWN

Check water level and water supply. Check set­ting of operating controls and burner equipment. Start burner and slowly bring boiler up to pressure. Observe functions of all controls during normal operations.

Maintain normal water level at all times. This is usually 4 inches below steam drum center line. Gage glasses should be blown down on a regu­larly scheduled basis. Illumination of the glass should be provided and any leakage or breakage of glass should be promptly repaired.

Blow down the boiler at regular intervals on a schedule based upon analysis of the water. Make any necessary adjustments to the con .. nuous blowdown valve as indicated by a test analysis. Refer to the blowdown section of this manual.

When operating with oil as the fuel, soot blowers ····-sheul4be..opel'a ted-Fegulal'lyto.k~p-gaspa.gsages

free from soot and to maintain normal tempera­tures and efficiency. Refer to the section on soot blowing in this manual.

ROUTINE SHUTDOWN

Operate all soot blowers before taking the unit off the line, if oil is the fuel being used.

Gradually reduce load and run burner to low fire position.

With the burner in low fire position, blow down boiler along with the water column gage glass and the feed water regulator. Turn the burner off

in accordance with instructions in the burner manual. Follow instructions in regard to burner shutdown conditions. When shutting down a gas fired burner, it is good practice to close the manual gas shutoff cock.

When the boiler falls below line pressure, the non-return valve should close automatically to isolate the unit from those remaining in service. On a single installation or if no other boilers are in service, the stop valve should be closed when the boiler setting has cooled enough to insure no pressure build up. When the drum pressure falls below 25 psi, open the top drum vent valve. This will prevent a vacuum that can loosen well set gaskets and cause future leaks.

The boiler should be filled with treated hot water in preparation for the next start up. Additional water care may be necessary and recommended by the feed water consultant if the shutdown is prolonged.

During an extended shutdown, the drain valves under the furnace floor and the convection section should be opened to permit any leaking water to escape. Close valves during operation.

E. OPERATING PROCEDURES 1. FEED WATER REGULATION AND CONTROL The boiler is standardly equipped with a thermo­hydraulic, single element feed water regulator which will automatically maintain the proper water level when used with a suitable source of water supply.

Refer to the manufacturer's literature, provided separately, for specific instructions on the feed­water regulator. The generator portion must be properly filled with liquid - either water (pre­ferably distilled) or with an anti-freeze solution, if conditions require.

When placing the boiler into service, the drum level must be maintained manually until the boiler has reached operating pressure. Manual control is accomplished through the manual operation of the bypass valve orby locking the regulator valve open with its hand jack lever and throttling the adjacent hand valve to keep the drum water level in the center of the gage glass.

To switch from manual to automatic operation, release the regulator valve hand jack and open wide the hand valve ahead of the regulator valve.

If the regulator fails to maintain proper water level during normal operation, refer to the manu­facturer's instructions for corrective adjustment.

The regulator and water column are factory piped at the proper levels and generally need no alteration. '

Chapter 2 - Operations. and Procedures

2. WATER LEVEL INDICATING SYSTEM The water level alarm system employs electrodes or probes mounted in a water column. These are electrically connected to relays in the limit and alarm circuits. The action of the relay depends on electrode immersions to complete each circuit. See Figure 3-1 and also refer to the wiring dia­gram provided for the boiler.

A minimum of 4 circuits is always provided al­though individual installations may have addi­tional. The four circuits are comprised of two low water cut-off circuits, a low water alarm circuit, and a high water alarm circuit.

Electrodes numbered 1 and 4 serve as low water cut-offs. Each of these is connected to an indivi­dual relay. A third electrode, identified as C, is a common electrode wired to all relays.

As long as these three are immersed, the water level is considered suitable for operation and the relay contacts are closed to complete the limit cir­cuit. Should the water level lower to the point where these are no longer immersed, the limit cir­cuit will be interrupted and the burner will shut down or be prevented from operating.

To assure adequate water level above the cutoff level, a shorter electrode identified as No. 2 is wired to a low water alarm relay. This electrode is normally immersed. Should this electrode be exposed by lowering water level, the alarm horn (AH) will sound and the low water light (LWL) will glow to alert the operator to this condition. This protection occurs while the burner is in operation or when the burner switch is closed in anticipation of operation.

Normally electrode No.3, which is connected to a high water alarm relay, will not be immersed. If the water level reaches the height of this elec­trode, the relay will be energized to sound the alarm horn and light the high water light (HWL).

An alarm test switch (A TS) is provided to simu­late alarm conditions when depressed so that a check may be made to determine that the alarm signal devices are in working order without disturbing burner operation.

The need to periodically check water level con­trols and the waterside of the pressure vessel can­not be overemphasized. Most instances of major damage are the result of operating with low water or the use of untreated (or incorrectly) treated water.

Low water cut-off devices are generally set by the original manufacturer and no attempt should be made to adjust these controls to- alter the point of low water cutoff. If a low water device should be­come erratic in operation or if its setting changes

2-3

Chapter 2 - Operations and Procedures

from previous established levels check for reasons and correct: repair and replace device as required.

Figure ~l is a replica of the low water cut-off plate attached to a steam boiler. The instructions should be followed on a definite planned schedule. These controls normally function for long periods of time which may lead to laxity in testing on the assumption that normal operation will continue indefinitely_

If the boiler is equipped with a float type water column or an auxiliary low water cut-off, the head mechanism should be removed from the bowl at least once a month to check and clean the float ball, the internal moving parts, and the bowL

Periodically remove the pipe plugs from the tees or crosses to make certain the cross connecting piping is clean and free of obstructions_ Controls must be mounted in a vertical position for proper performance. Determine that piping is vertically aligned after shipment and installation and throughout life of equipment.

A scheduled blow down of the water controls should be maintained.

WARNING SAFE OPERATION OF YOUR BOILER DEMANDS PERIODIC INSPECTION AND MAINTENANCE OF ALL lOW WATER CUT -OFF DEVICES. INSPECT THEM AT LEAST ONCE A MONTH. PROPER OPERATION SHOULD BE CHECKED PRE­QUENTLY BY CLOSING FEED WATER VALVE WITH BOILER IN OPERATION AND ALLOWING WATER LEVEL TO OROI' AT A NORMAL RATE. IF CONTROLS UNDER TEST 00 NOT CUT OFF BURNER AT PROPER SAFE WATER LEVEL OR ARE SEEN TO BE IN POOR PHYSICAL CONDITION, REPAIR OR REPLACE AT ONCE. MUD AND SEDIMENT ACCUMA­LATIONS IN THE GAGE GLASS, WATER COLUMN, AND AUXILIARY LOW WATER CONTROLS SHOULD BE ELIM-

,-INATED BY PROPER BLOWDOWN PROCEDURE. ~

FIGURE 2-1 LOW WATER CUT-OFF PLATE

3. THE WATER COLUMN

In addition to the probes described in the pre­vious section, the water column also contains the equipment to provide the operator with visual knowledge of the water leveL

The gage glass attached to the side of the column is used to visually check the boiler water leveL The trycocks can be used to check the accuracy of the gage glass levels. The gage cocks provide a means of isolating the gage glass in the event of the breakage or replacement.

2-4

This visual knowledge of the water level is one of the most important operating guides available to the operator. The importance of frequent ob­servation of the water level cannot be over­emphasized.

Keep the gage glass clean and properly lighted for good visibility. Refer to the operating and maintenance section of this manual for blowdown test procedures and replacement.

Operate the gage cocks regularly to insure their being satisfactory for emergency service.

The normal water level in a Cleaver-Brooks Watertube Boiler is 4" below the center of the steam drum. This level is indicated at the mid point of the gage glass.

The low water alarm probe is usually positioned to be energized should water fall approximately 5" below normaL The alarm signal will alert the operator of this condition.

Should water level fall to approximately to 1/2" visibility in the gage glass, the low water cut off probe will be exposed and will act to shut down the burner.

The ASME Boiler and Pressure Vessel Code requires that the lowest visible point of the water glass shall be at least 2" above the lowest per­missible water level. This is the point at which there will be no danger of overheating any part of the boiler when operation is at that level.

CAUTION: In the event the burner is firing at any time that water is not visible in the water gage glass, immediately turn the burner off manually. DO NOT TURN ON THE WATER FEED LINE.

DO NOT OPEN THE SAFETY VALVE. Let the boiler cool until a drum is at hand touch tem­perature. Then add water to a height of 1" in the gage glass. DO NOT PUT THE BOILER BACK INTO SERVICE UNTIL THE CONDITION RESPONSIBLE FOR THE LOW WATER HAS BEEN IDENTIFIED AND CORRECTED. Do not attempt to put the boiler back into operation if there is evidence of overheated metal, or even suspected damage, until a thorough inspection and/or repairs have been made_

Check the water gage on a regular basis. A weekly frequency is suggested. The check should be made when there is steam pressure in the boiler. Close the lower gage glass valve, then open the drain cock on the bottom of the valve and blow the glass clear. Close the drain valve and open the lower gage glass valve. Water should return to the gage glass immediately_ If

water return is sluggish, leave the lower gage glass open and close the upper gage glass valve. Then open the drain valve and allow water to flow until it runs clear. Close the drain valve and repeat the first test with the lower gage glass valve closed.

If leaks appear around the water gage glass or fit­tings, correct the leaks at once. Steam leaks may result in a false water line and may also damage fittings.

The handles on the gage glass cocks must be in­stalled on the valve stems so that their position indicates whether the valve is open or closed. The operating chaifi on the right hand side of the levers should be snug between levers so that both valves will be closed tight when the chain is pulled from below.

4. SLOWDOWN

Boiler water blowdown is the removal of some of the concentrated water from the pressure vessel while it is under pressure. The removed water containing suspended solids and dissolved solids is replaced with relatively' pure feedwater so that a lowering of the concentration occurs.

Solids are brought in with the feedwater even though this water is treated prior to use through external processes designed to remove the un­wanted substances which contribute to scale and deposit formations. Regardless of their high ef­ficiency, none of these processes in themselves are capable of removing all substances and a small amount of encrusting solids will be present in the boiler water.

The solids become less soluble in the high tem­perature of the boiler water and as the water boils off as relatively pure steam, the remaining water becomes thicker with either suspended solids or dissolved solids.

Internal chemical treatment, based on water analysis, is used primarily to precipitate many of the solids and to maintain them as "sludge" in a fluid form. This sludge along with suspended solids that may be present must be removed by the blow down process.

If the concentration of solids is not lowered through blow down but rather accumulates, foam­ing and priming will occur along with scale and other harmful deposits.

The scale forming salts tend to concentrate and crystalize on the heating surfaces. Scale has a low heat transfer value. It acts as an insulation barrier and retards the transfer. This not only re­sults in low operating efficiency and consequently higher fuel consumption, but also presents the

Chapter 2 - Operations and Procedures

possibility of overheating the boiler metal. The result can be tube failures or other pressure vessel metal damage causing costly repairs and downtime. Deposits of sludge on heating surfaces will have the same detrimental effect.

There are two principal types of blowdown; in­termittent and continuous. Intermittent, or sludge, is done manually and is necessary for the operation of the boiler regardless of whether or not continuous blowdown is employed. Continu­ous blowdown is, as the name implies, a continu­ous and automatic removal of concentrated water.

Manual Slowdown

The manual blowdown valve and discharge lines are located at the bottom or low point of a boiler so that in addition to lowering the dissolved solids in the boiler water, a portion of sludge which might accumulate in the lower part of a pressure vessel can also be removed. This opening also provides a means of draining the boiler when it is not under pressure.

When continuous blow down is utilized, manual blowdown is primarily used to remove suspended solids or sludge that may have accumulated in the area. When continuous blowdown is not utilized, manual blowdown is used to control the concentration of dissolved or suspended solids in addition to the sludge.

In practice, the valves of the bottom blowdown are opened periodically in accordance with an operating schedule and/or chemical control test. The blowdown amount and schedule should be recommended by a water treating company or a water consultant. It is generally recommended that a steam boiler be blown down at least once in every eight hour period. In cases where the feed water is exceptionally pure, blowdown may be employed less frequently since less sludge ac­cumulates in the pressure vessel.

From the standpoint of control, economy, and re­sults, frequent short blows are preferred to infre­quentlengthy blows. This is particularly true when the suspended solids content of the water is high. With the use of frequent short blows, a more uniform concentration of the pressure vessel water is maintained. Blowing down is most ef­fective at a time when the generation of steam is at the lowest rate since the feed water input then is also low, providing a minimum dilution of the boiler water with low concentration feedwater.

Make sure that blowoff piping, and tank if used, are in proper operating condition, all discharge vents clear of obstruction and that waste is piped to point of safe discharge.

2-5

Chapter 2 . Operations and Procedures

It is recommended that the blowdown valve near­est the boiler be opened first and closed last, with blowing down being accomplished by the valve furthest from the boiler. The sequence of opera­tion oncs established should provide that the valve last opened should be the first closed so that the other valve is saved from throttling ser­vice to insure a tight closing.

Th~ downstream valve should be cracked slightly to allow the discharge line to warm up, after which this valve is opened slowly. Quickly close the valve, and if necessary, repeat this opening and closing.

Close the downstream valve tightly, then close the valve next to the boiler. Slightly crack open the downstream valve, then close it tightly. The frequency and amount of each blow should be determined by actual water analysis. It is advis­able that blowdown does not exceed the necessary amount since it involves heat losses and, if ex­cessive, wastes treatment chemicals.

The water level should be observed during periods of blowdown. If the glass cannot be viewed by the party operating the valve, another operator shou.ld watch the glass and direct the valve operator. The blowoff valves should never be left open and the operator should never leave until the blowdown operation is completed and the valves closed. Be sure the valves are shut tight. Repair any leaking valves as soon as possible.

Continuous Blowdown

The boiler is equipped with an internal continu­ous blowdown pipe and an external stop valve. Th.e collector pipe is located several inches below the low water level at a point where the most con­centrated water is found.

A controlled orifice valve is used in the discharge pipe to allow continual, yet controlled, flow of concentrated water. This removes sediment and oil from the surface of the water along with the prescribed amount of dissolved solids ..

·-~-tn-'a····boileri:hat-\)perates·-continuoustr-at· full·· load, there is little chance for separation of sludge in the lower drum because of the rapid boiler water circulation. Thus, blowoff from the lower part of the unit may not result in the proper elimination of suspended solids. The use, how­ever, of the continuous blowdown does not pre­clude the regular use of the bottom or inter-. niittent manual blowdown.

The amount of water lost through a continuous surface blowdown is usually considerably less than the water lost through bottom blowoff in or­der to remove a given amount of suspended

2-6

solids, The amount of 'blowdown depends upon the rate of evaporation and the amount of siudge forming material in the feedwater.

Periodic. adjustments are made to the valve set­ting to increase or decrease the amount of blow­down in accordance with a test a·nalysis.

Internal inspection is the only true indication of the effectiveness of water treatment and presence of unwanted solids.

5. SOOT BLOWING

Systematic soot blowing should be included as a regular feature in the operation of any oil burn­ing watertube steam boiler. The frequency and amount of cleaning will depend upon operating conditions, grade of fuel and burner adjustment. Experience will dictate the length of cleaning and the interval between.

The following guidelines should be observed.

The soot blower must be operated only when the burner is firing at a rate of 70% or higher, Place the burner under manual operation, if necessary, to 'hola the boiler at near maximum firing rate despite load variations.

Operating at low loads should never be at­tempted because of the possible hazards involved. It is important to have all areas of the gas passes thoroughly swept by utilizing maximum flue gas flow to purge any combustible material from pockets where it may collect. Cleaning operations during a low firing rate may produce unfavorable conditions that could interrupt combustion.

Prior to blowing, the drain valve in the steam line to the soot.blower should be opened. Then open the steam shut-off valve slowly and vent steam for approximately five minutes to insure that no water is present in the steam line and to warm the piping. -Close the vent valve.and begin rotat-

.... _ing. .. the~.elem.eD.t .. _ ....... .

Rotate with a steady pull on the chain wheel and be sure to keep rotating whenever steam is issu­ing from the nozzles.

The amount of cleaning, or number of times the element is rotated, can be governed by observing exit temperature or stack discharge.

A generally recommended pract.ice is to op~rate all soot blowers prior to taking a boiler off line.

At the conclusion of blowing, close the steam header valVE!. The factory installed drain valve has a small·hole drilled in its gate to allow escape

of steam and condensate. If the drain valve wall provided by others, open it to drain the line.

The blowing pressure is adjustable and should be set in a range of 80 to 150 psi. Refer to the manu­facturer's bulletin for instructions on pressure ad­justment.

Maintenance:

Follow the manufacturer's recommendations for lubrication of the gears and head. Keep the pack­ing glands just tight enough to prevent leakage, but do not overtighten. Also examine to the ex­tent possible the external surfaces of the tubes adjacent to the element nozzles for any signs of abrasion possibly caused by movement of the ele­ment due to distortion or shifting.

Air, taken from the blower discharge, is piped to the head so that it and the element are suffici­ently pressurized to prevent the backup of com­bustion gases from the pressurized furnace. Periodically check the condition of the airline to make sure there are no obstructions or loose con­nections. Also, inspect the air check valve on the head for free operation.

6. SUPERHEATER

General

Correct operational procedures must be followed during the starting up and shutting down of a boiler equipped with a superheater to prevent damage from occurring to the superheater tubes. It is essential that definite procedures be established and followed by all operators.

Start-up

A moderate firing rate (generally about 10% of maximum) must be used during start-up and dur­ing the warming up of a cold boiler and super­heater. The addition of heat too rapidly may in­crease the superheater metal temperature to a point where it will oxidize or "burn". The control

. system~generarryiiiaudesa-rowfire~pressure con­trol that limits the burner to low fire operation until the boiler pressure reaches approximately one-third operating pressure (or approx. 50 psi).

When starting the boiler, the superheater vent valve must be opened until the non-return valve is opened and steam flow through the system is established. This keeps steam flowing through the superheater tubes. It is imperative that a positive flow of steam be maintained whenever the super­heater is subjected to heat. The heat absorbed by the superheater must be carried away at the same rate that is transmitted to the tubes.

Chapter 2 - Operations ·and Procedures

When boiler pressure reaches 15 to 25 psi, close the drain valve but leave the vent valve wide open. A tendency may exist to throttle the vent valve in order to save steam or to raise pressure at a faster rate. While this is not without some advantage, it is more desirable to protect the superheater by leaving the vent valve open until the boiler is on the line and with a definite (not less than 10%) flow of steam into the system.

A steam temperature recorder or thermometer should be installed on the upstream side of the vent valve and as close to the outlet of the super­heater as practical. Temperatures taken at a more remote point may not provide true super­heater temperature readings. Steam flow tem­perature at this point can then be a fairly ac­curate temperature indicator of the superheater tube metal and the rate of firing can be con­trolled within a safe range. The temperature should increase gradually and should, in general, be well below the maximum temperature for which the superheater was designed. Tempera­tures approaching this maximum will indicate that the firing rate is too high. In this event, the firing rate should be decreased or stopped alto­gether.

An accepted rate of boiler water temperature rise for a steam boiler is approximately 80°F. per hour. The protection of the superheater is the pri­mary factor controlling the time required for placing the boiler into service.

Normal Operation

During normal operation, the superheater re­quires no special safeguards other than the main­tenance of the conditions for which it was designed.

When firing on oil, use the soot blower on a regu­larly scheduled basis to keep the superheater sur­faces free of soot or other deposits. Periodically check for effectiveness and also on the alignment of the steam jets.

.. J'h~ !!!lperl1~A!~r..ha!l~a!!aJl:!ty. YaJYI:! th.1ij;i!l..!!~t to open at a lower pressure than the boiler safety valves. In the event of excessive steam pressure, this valve will open first so that steam from the boiler will continue to flow through the super­heater tubes. If the boiler pressure is not dissi­pated or the fire reduced, the boiler safety valves will then open.

Shutting Down

During the shutting down operation, it is also necessary to maintain steam flow through the superheater. The vent valve should be opened as the boiler is taken off the line. The drain valve

2-7

Chapter 2 . Operations and Procedures

should I:emain closed. An acceptable practice is to open the vent valve fully when the boiler is first taken off the line and then to close it in gradual steps as furnace temperature decreases. The amount 'Of valve opening can be based on the temperature of the steam indicated by the thermometer in the superheater outlet.

When the furnace is cool, the valve may be closed. In some multiple unit installations, the boiler may be kept on standby service with ·its water kept hot through introd!lction of steam from another unit and in this event, the vent valve should rem'ain open.

2-8

If the boiler is removed from service, open all drain valves to drain water caused by condensa­tion. The superheater should be visually examined during the annual inspection and, if possible, during other down periods. Check the in­ternal surfaces for scale, corrosion, also for evidence of leaks or overheating. Replace the gaskets in the header handholes. Make sure that gasket seating surfaces are clean.

If the boiler is to be idle for any length of time, follow the instructions in this manual pertaining to the care and protection of idle boilers.

Chapter 3 . Maintenance

CHAPTER 3

MAINTENANCE A. GENERAL

WATERSIDE INSPECTION FIRESIDE INSPECTION

B. PRESSURE VESSEL CARE AND REPAIRS

C. TUBE CLEANING MECHANICAL TUBE CLEANING CHEMICAL CLEANING

D. WATER COLUMN PROBE INSTALLATION GAUGE GLASS OR PRISMATIC INSERT

E. SAFETY V ALVES

F. CARE AND PROTECTION OF IDLE BOILERS

A. GENERAL

A well planned maintenance program avoids un­necessary down time or costly repairs, promotes safety and aids boiler code and local inspectors. An inspection schedule listing the procedures should be established. It is recommended that a boiler room log or record be maintained, re­cording the daily, weekly, monthly and yearly maintenance activities. This provides a valuable guide and aids in obtaining economies and length of service from the boiler.

Even though the boiler has electrical and me­chanical devices that make it automatic or semi­automatic in operation, these devices require systematic and periodic maintenance. Any "auto­matic" features do not relieve the operator from responsibility, but rather free him from certain repetitive· chores, providing him time to devote to upkeep and maintenance.

Good housekeeping helps maintain a professional appearing boiler room. Only trained and authorized personnel should be permitted to operate, adjust, or repair the boiler and its re­lated equipment. The boiler room should be kept free of all material and equipment not necessary to the operation of the boiler or heating system.

Alertness in recognizing an unusual noise, im­proper gauge readings, leaks, signs of over-heat­ing, etc., can make the operator aware of a de­veloping malfunction, permitting prompt correc-

tive action that may prevent excessive repairs or unexpected down time. A steam, water, or fuel leak should be repaired as soon as possible. They are wasteful as well as hazardous.

Always be sure of the boiler water level. The water column should be blown down at least once each eight hour shift. Check samples of boiler water and condensate in accordance with pro­cedures recommended by your water consultant.

Daily maintenance should include a check of the burner operation, including fuel pressure, atomiz­ing air or steam pressure, visual appearance, etc. Clean the observation ports during periods of low fire or shutdown.

Maintain a daily schedule of soot blowing and in­termittent blowdown. Refer to previous sections for additional information.

WATERSIDE INSPECTION

Insurance regulations or local laws will require a periodic inspection of the pressure vessel by an authorized inspector. Sufficient notice is generally given to permit removal of the boiler from service and preparation for inspection.

Inspections of thi.s type are usually, though not necessarily, scheduled for periods of normal boiler down time 'such as an off season. This major inspection can often be used to accomplish maintenance, replacements or repairs that cannot

3-1

Chapter 3 - Maintenance

easily be done at other times. This also serves as a good basis for establishing a schedule for an­nual, monthly or other periodic maintenance programs.

While this inspection pertains primarily to the waterside and fireside surfaces of the pressure vessel, it provides the operator an excellent op­portunity for detailed inspection and check of all components of the boiler including piping, valves, pumps, gaskets, refractory, etc. Comprehensive cleaning, spot painting or re-painting and the re­placement of expendable items should be planned for and taken care of during this time. Any major repairs or replacements that may be required should also if possible be coordinated with this period of boiler shutdown.

Replacement spare parts, if not on hand, should be ordered sufficiently prior to shutdown.

When shutting down, the load should be reduced gradually and the pressure vessel cooled at a rate that avoids damaging temperature differential that can cause harmful stresses. Vessels should not normally be drained until all pressure is re­lieved and water temperature is less than 120°F. -again to prevent uneven contraction and tem­perature differentials that can cause expanded tubes to leak. Draining the unit too quickly may cause the baking of deposits that may be present on the heating surfaces. Some heat, however, may be desirable to dry out the interior of the boiler.

If the internal inspection is being made at the re­quest of an authorized inspector, it is well to learn from him whether he desires to observe the conditions prior to cleaning or flushing of water­side surfaces.

Be certain that a supply of manhole gaskets is available along with any other gaskets or items needed to place the unit back into operation after inspection.

Have availabl€"'information on the boiler design, dimensions, generating capacity, operating pressure ox temperature; time in serviBe, defects found previously and any repairs or modifi­cations. Also have available for reference records of pr.evious inspections.

Be prepaKed to perform any testing required by the inspector including hydrostatic.

After proper cooling and draining of vessel, flush out the waterside with a high pressure water hose. Remove any scale or deposits from the waterside surfaces and check for internal or ex­ternal corrosion and leakage.

The fireside surfaces should also be thoroughly cleaned so that metal surfaces, welds, joints, tube

3-2

ends, fittings' and any previous repairs can be readily cMcked.

Be sure that steam valves, system valves, (hot water) feedwater valves, blow-off valves, all fuel valves, valves to expansion tanks, and electrical switches are shut off'prior to opening the drums or the combustion area. Adequately vent the presslJ,re vessel prior to entry. Flashlights rather than ex­tension cords are recommended as a safety factor. Cleaners should preferably work in pairs. Always have one man standing by outside when a man is working inside a boiler.

Clean out the low water cut-off piping, the water level controls and cross connecting piping. Re­place water gage glass and clean out water cocks and tri-cocks. Also check and clean drain and blowdown valves and piping.

Check all water and steam piping and valves for leaks, wear, corrosion and other damage. Replace or repair as required.

If any deposits are noted during these inspections, they should be flushed out with a high pressure hose. If they are not thoroughly removed by flush­ing, this may require immediate consultation with your water treatment representative. In a few cases, it may be necessary to resort to acid cleaning. Professional advice is definitely re­commended should acid cleaning be required.

The effectiveness of treatment, water conditions and the amount of fresh water makeup required are all factors to be considered in establishing frequency of future pressure vessel inspections. The feedwater consultant or water treatment companies service should include periodic pressure vessel inspection and water re-analysis.

FIRESIDE INSPECTION

An internal, or fireside, inspection should be made at least semi-annually and oftener if pos­sible. Wire brush or sweep away any deposits that might be present in the furnace area. If excessive soot or any signs or corrosion are evident,prompt co:n:ective action must be taken. Combustion ad­justments should be made to prevent further oc­currences. Poor combustion contributes to a dirty boiler, adds hazards and wastes fuel.

Check the condition of all the refractory. Parti­cularly check the expansion joints in the fmnt and rear walls, the seals at the corners and the throat tile. Patch and repair as required.

Frequent wash coating of refractory surfaces is recommended. Use high temperature bonding, air-dry type mortar diluted with water, to the consistency of light cream, for this purpose. This

will seal small cracks and prolong the life of the refractory. Any large cracks should be cleaned out and filled with mortar.

The breeching and stack should be inspected periodically and cleaned if necessary. Also in­spect the stack for -any signs of damage.

The fireside should be thoroughly cleaned prior to any extended lay-up of the boiler.' Depending upon circumstances a protective coating may be required. See the section on storage.

B. PRESSURE VESSEL CARE AND REPAIR

A well maintained and operated boiler with pro­perly treated water will require a minimum of re­pairs. Periodic inspection of the pressure vessel will reveal its' condition, oftentimes permitting corrective action designed to prevent failure of some portion of the boiler.

Corrosion and erosion, or a combination of both, are a chief cause of tube failure. Corrosion is a chemical action occurring inside or outside the tube wall. Internal corrosion appears as pitting or a general failing of the tube walL Pitting oc­curs when there is free oxygen in the water where­as general thinning indicates an acid condition in the boiler water. External corrosion is very likely to occur when a full boiler covered with soot lies idle. Most soot contains some percentage of sulfur which in the presence of moisture from condensa­tion forms a highly corrosive acid.

Erosion takes place when considerable quantities of fine particles are driven at high velocity against the outside surfaces of the tubes. Erosion may also be caused by soot blowers if nozzles are not kept in proper alignment.

Over-heating also contributes to damage. This usually occurs when a tube is heated to a tem­perature which reduces its tensile strength. The weaker walls then rupture under normal opera­ting pressure. The chief cause of over-heating is scale on the water side of the tubes. Scale is a poor conductor of heat and the cooling ability of the boiler water is lessened: Low water is another cause of over-heating since circulation of water is impaired and the tube is starved of water. An oily film also acts as an insulator permitting over­heating. Any sign of oil in the boiler should be considered serious and prompt action taken to remove it.

Over-loading a boiler to produce more steam than intende'd by its design.will also shorten the boiler life, with the tubes being first to suffer.

Chapter 3 - Maintenance

If small leaks occur, locate their source and. re­pair them as quickly as possible. Leaking man­holes and handholes should be corrected promp­tly. Gasket sealing surfaces should be cleaned thoroughly to provide a tight seal.

In the event of a serious leak or a tube failure, shut down the burner and the supply of feed­water. When steam pressure has dropped to zero, continue the cooling process in the normal man­ner. Then conduct a thorough inspection to deter­mine the extent of damage.

No repair of any type is to be made until pressure is removed from the boiler. Observe all safety pre­cautions before entering the boiler for inspection or repairs. This includes securing the burner and positive action in insuring all valves in lines to and from the boiler are closed and remain closed. Minor or leaking repairs may be handled by authorized and experienced personnel. Any re­pairs beyond this must have the approval of an authorized inspector. His recommendations and advice must be followed. If welding is required, the welder must be certified to do the work.

Boiler tubes are secured in the boiler drums by rolling or expanding to a tight fit. In the correction of any leak, it is imperative that rerolliJ;lg of the leaking tube be done only be experienced person­nel. Inexperienced operators tend to overroll the tube, thus thinning the joint and making it difficult to tighten under any circumstances. When seal welding is employed, a light rerolling should be made after welding.

C. TUBE CLEANING

1. MECHANICAL TUBE CLEANING

The mechanical method of cleaning water tubes, referred to as turbining or punching, is ac­complished through the use of motor driven ro­tary cutting tools and brushes. The necessity for and frequency of this type of cleaning is deter­mined by an internal inspection. The type of de­posits will determine the ne-ed Jor using cutting or scraping tools and a brush 01' a' brush only. Air driven tools are most commonly used although water driven tools are also employed. Steam driven and electric driven tools are used infre­quently. Cleaning tools furnished by or obtained from Cleaver-Brooks are selected for the size of the boiler tubes and for their ability to negotiate the bends of 'the tubes.

The mecnanical cleaning of tubes and the use of these tools should be 9,one by experienced opera­tors or at least under their supervision. There are companies who specialize in cleaning and their

3-3

Chapter 3 . Maint.enance

experience and equipment will quite often justify their employment.

This work is generally done from within the up­per drum, working the tool down through the tubes so that debris falls into the lower drum from. where it can be collected and removed. The baffle plates in the upper drum will have to be reo moved -for access to the tubes.

There are several general operating suggestions that should be followed as good operating prac­tices:

a) Start the cleaner rotating in the tube and l1ass it slowly and uniformly through at ap­proximately two to three feet per minute.

b) Do not allow cleaner to protrude from the tube while under power. This can be danger­ous to personnel and damaging to equip­ment.

c) Care should be taken not to allow the cleaner-.to stop in anyone position in the tube.

d) Keep working tools in good condition. e) If electrical driven tools are used, be sure

they are properly grounded.

The following specific operating instructions are provided by Thomas C. Wilson, mc. - Manu-

• facturer of tube cleaning equipment.

OPERATING I~STRUCtIONS FOR AIR DRIVEN CLEANER

RECOMMENDE·D OPERATING AIR PRESSURE 90 PSI. MAY BE OPERATED AT 60 TO 100 PSI.

HOW TO SET ~UP THE TUBE CLEANER:

L Blowout air line before attaching operating hose in order to remove all dirt, rust, or other foreigp- matter.

2. Attach automatic lubricator (if included in your equipment) to air outlet. Connect hose.

3. Blowout the air-line and hose again.

4. Connect the tube-cleaner air v?lve (if included in your equipment) to the hose.

5. Attach motor, making sure connections are wrench-tight - buf not jammed - to prevent air leakage.

6. Using wrench supplied with equipment, screw universal joint or flexible holder to motor.

7. Attach the cleaning .or brushing tool.

HOW TO OPERATE -T~E TUBE CLEANER:

L Insert the cleaning tool into the tube, then open the air valve and feed the motor into the tube slowly enough to properly clean the tube.

3-4

2. Don't let the cleaning tool run out of the end of the tube - you'll damage it. A good prac­tice is to mark the operating hose with tape or other visible marking to indicate exa-ct length of tube.

3. Keep the motor running when pulling it back through the tube.

4. Shut off the air and stop the motor before tak­ing it out of the tube.

5. If cleaning tool jams in deposit, pull motor back gently to release it. CO.ntiriue cleaning.

6. If motor functions improperly, it is probably due to faulty lubrication or dirt in the air-line. Take motor apart and clean all parts, includ­ing the rotor blades, with kerosene.

LUBRICATION:

L To lubricate the motor, use one part Wilsolube No. 9047 oil to two parts kerosene.

2. The needle valve on the automatic lubricator controls the feed of oil to the motor. Feed 10 to 20 drops per minute depending on the size of cleaner. This small amount of oil will not coat the tubes. It will be absorbed and blown out with the debris .

3. If you do not have an automatic lubricator use an oil can to apply a few drops of oil into the exhaust ports of the motor. Turn the motor by hand to distribute the oil and then blowout motor before inserting into the tube.

4. KEEP MOTOR LUBRICATED.

HOW TO PREVENT RUST AND CORROSION IN STORAGE:

1. Before storing your tube cleaner, clean and oil it thoroughly with machine oil to prevent rusting.

2. The best method of storing straight tube motors is to keep them in oil.

3. Curved tube motors, - suspend the motor in 011 keeping the hose piece above the level of the oil as the hose piece will not stand pro­longed immersion in oil.

OPERATING INSTRUCTIONS FOR WATER DRIVEN CLEANER

The operation of the water driven cleaner is essentially the same as the air driven type with the following changes or instructions:

1. The water line from the pump to the hose con­nection should be larger than the hqse fur­nished with the water motor: If the water sup'"

ply is not free of sediment, be sure to use an adequate strainer.

2. Motors should be operated at pressures of 125 to 175 lbs. psi. Consumption will vary from 20 to 30 gpm depending upon motor size and operating pressure.

3. The water acts as a lubricant, therefore no lubrication is necessary.

4. After using, it is a good policy to disassemble motor, thoroughly clean and dry, oil and store in a dry place.

2. CHEMICAL CLEANING

Should. a waterside inspection reveal a deposit build-up that cannot be fully removed by flushing or mechanical means, it may be necessary to clean with chemicals (acid). Professional advice is recommended. There are specialist companies equipped to provide complete chemical cleaning service. Your feedwater consultant should be con­tacted and be aware of the situation.

D. WATER COLUMN

1. PROBE INSTALLATION INSTRUCTIONS

Thread electrode probe into holder finger tight. Lock in place using a wrench on lower hex and another on the lock nut. Do not use a wrench on the upper hex while installing the probe. See Figure 3-1. .

Clean the female threads in the water column plate. If they require chasing, use a 3/8" SAE DRY SEAL (PTF) tap. Do not use a standard 3/8" NPT tap. Teflon tape or a small amount of pipe dope may be used on the male threads. Use a 13/16" deep socket wrench on upper hex to tighten electrode holder. Take care not to crack the insulator.

When attaching the wire lug use proper wrenches on both lug nuts so that no torque is applied to the electrode holder. Do not use a knurled nut or 10ck washer.

2. THE GAGE GLASS OR PRISMATIC GAGE INSERT

When a tubular glass is used, it is imperative that the gage cocks are mounted in exact alignment. If they are not, the glass will be strained and may fail prematurely.

A broken or discolored glass should be replaced at once. Periodic replacement should be a part of the maintenance program. Always use new gaskets when replacing a glass. Use a proper size

Chapter 3. - Maintenance

rubber packing. Do not use "loose packmg which could be forced below the glass and pos­sibly plug the valve opening.

Close the valves when replacing the glass. Slip a packing nut, a packing washer, and packing ring onto each end of the glass. Insert one end of the glass into the upper gage valve body far enough to allow the lower end to be dropped into the lower body. Slide the packing nuts onto each valve and tighten. See Figure 3-2.

If the glass is replaced while the boiler is in ser­vice, open the blowdown and slowly bring the glass to operating temperature by cracking the gage valves slightly. After glass is warmed up, close the blow down valve and open the gage valves completely.

If the water c.olumn is equipped with a prismatic gage insert, it should be inspected for leakage af­ter it has been placed in service. When thoroughly heated, expansion of the metal parts causes the bolting pressure to ease somewhat and if leakage is apparent, it is advisable to go over to the bolts and tighten them lightly and evenly to prevent further leakage. See Figure 3-3.

To clean or replace the prismatic glass, remove the insert from the gage valves. Thoroughly clean the gasket seat surface after the old glass and gaskets have been removed. The surface must be smooth and free from scratches to prevent shat­tering the replacement glass.

The inner gasket and the glass should be placed centrally on the insert body. Be careful that they remain correctly located when the outer or cushion gasket and cover plate are placed in posi­tion. Put all the clamps, washers, and nuts loosely on the studs. Finger tighten all of the nuts first. Then starting from the center pair of nuts, tighten in alternate pairs towards either end. Tighten each nut about one sixth revolution at a time. Go over the nuts enough times to draw them all up to 35 to 40 foot pounds of torque.

After mounting the insert in the valves, open the blowdown valve and slowly bring the glass up to operating temperature by· cracking the stea.m valve slightly to allow a small amount of steam to heat the insert. When thoroughly heated, close the blowdown valve and open both steam and water valves. .

Figures and gauge replacement information cour­tesy of the Clark Reliance Corporation.

E. SAFETY VALVES

The safety valve is a very important safety device on the boiler and deserves attention accordingly.

3-5

Chapter 3 - Maintenance

LOW WATER

PLUGGED TAPPINGS FOR OPTIONAL EQUIPMENT

HIGH WATER ALARM FUEL CUTOFF *~~9--~~-

LOW WATER. ~~~'-~ __ (..LLOW WATER ALARM FUEL CUTOFF 873-96

ELECTRODE

~ ---

[iT (!)~

13/16" UPPER HEX-1~~~iit~~ -~ e,..:(

I' • ...1 ~

TOP HEAD OF WATER u....:( ~ I w~ ..:( COLUMN BODY

"

~w ...I = .... ..:( ~..:( ~ ,... 3:: w

.... 3/8" LOWER HEX ..:(

3:: 3:: 0 1/4" - 20 NUT :d. u.:

1/4" DIA. ELECTRODE w ~

= ~ ,...

...I W

u.: > II) w u.. W ...I u.. ~ 0 = ~ ....

~ w :::l ..... U N ..:(

~~ 3:: w Z ...I .... ~ ..:( ..:(~ ~ 3::0 ~

3:: u 0 0- Z

...10 NZ -:..:( 1L w ~

= O. N

Elec Wire Distance Function Top of Plote to

No. Term. Tip of Electrode 1 A Low Water Fuel Cut-off' ! 18·3{8" i 67-243 20" 2 E Low Water Alarm i 15·5/8" ; 67-242 17-1/4" 3 0 High Water Alarm 5·3{8" ! 67-241 7-1/4" 4 B Low Water Fuel Cut-off 118·3/8" ! 67-243 20" C C Common .18·3/8" I 67-243 20"

FIGURE 3-1 STANDARD WATER COLUMN ASSEMBLY

CROSS SECTION BEFORE TIGHTENING

FIGURE 3-2 TUBULAR GAGE GLASS

3-6

GLASS PACKING

MALLEABLE IRON CLAMPS

PRISMATIC GLASS

FIGURE 3-3

PRISMATIC GAGE INSERTS

MACHINE

BOLTS

(jASKETS

The purpose of the valve(s) is to prevent pressure build up over the design pressure of the pressure vessel. The size, rating and number of valves on a boiler is determined by the ASME Boiler Code.

The insta,llation of a valve is of primary import­ance to its service life. A valve must be mounted in a vertical position so that discharge piping and Code required drains can be properly piped to prevent build up of back pressure and accumu­lation of foreign material around the valve seat area. Apply only a moderate amount of pipe com­pound to male threads and avoid overtightening as this can distort the seats. Use only flat jawed wrenches on the flats provided. When installing a flange connected valve, use a new gasket and draw the mounting bolts down evenly.

A drip pan elbow or a flexible connection be­tween the valve and the escape pipe is re­commended. See Figure 3-4. The discharge piping must be properly arranged and supported so that its weight does not bear upon the valve.

NOTES: I. DIMENSION BETWEEN VALVE AND DRIP PAN ELBOW SHOULD BE

AS SHORT AS POSSIBLE. 2. DISCHARGE PIPING MUST BE fNDEPENDENTLY SUPPORTED SO

THAT NO S'rRAIN IS PLACE1> OK VALVE BODY. 3. ALL DRAIN LINES SHOULD BE INDEPENDENTLY SUPPORTED AND

PROPER EXPANSION PROVISIONS MADE TO ELIMINATE ALL STRAIN ON VALVE BODY.

~. ALLOW SPACE TO COMPENSATE FOR UPWARD EX PANS ION OF 80 I LER WHEN HOT.

5. PROVIDE 3 OR ~ EQUALLY SPACED SPACERS TO CENTER DISCHARGE PIPE. MUST BE FREE, TO ALLOW FOR EXPANSION.

FIGURE 3-4 STEAM SAFETY VALVE

Do not paint, oil, or otherwise cover any interior or working parts of the safety valve. A valve does not require any lubrication or protective coating to work properly.

Chapter 3 - Ma.intenance

Follow the recommendations of your Boiler In­spector pertaining to valve inspection and testing. The frequency of testing, either by the use of the lifting lever or by raising the steam pressure, should be based on the recommendation of your Boiler Inspector, and/or the valve manufacturer, and in accordance with section VII of the ASME Boiler and Pressure Vessel Code.

Avoid excessive operation of the safety valve as even one opening can provide a means of leakage. Safety valves should be operated only often enough to assure that they are in good working order. When a pop test is required, raise the oper­ating pressure to the set pressure of the safety valve, allowing it to open and reseat as it would in normal service.

Do not hand operate the valve with less than 75% of the stamped set pressure exerted on the underside of the disc. When hand operating, be sure and hold the valve in an open position long enough to purge accumulated foreign material from the seat area and then allow the valve to snap shut.

Frequent usage of the safety valve will cause the seat and disc to become wire drawn or steam cut. This will cause the valve to leak and necessitate down time of the boiler for valve repair or re­placement. Repair of a valve must be done only by the manufacturer or his authorized repre­sentative.

Avoid having the operating pressure too near the safety valve set pressure. A 10% differential is re­commended. An even greater differential is desir­able and will assure better seat tightness and valve longevity.

Steam is expensive to generate and, for the sake of economy, wastage should be avoided whenever possible.

F. CARE AND PROTECTION OF IDLE BOILERS

Many boilers used for heating or seasonal loads, or for standby service, may have extended periods of non-use. Special attention must be given to these, so that neither water side nor fire side sur­faces are allowed to deteriorate from corrosion. Corrosion can be more serious during this down time than when the boiler is actually in service.

Too many conditions exist to lay down definite rules. There are two methods of storage -- wet or dry. Your water consultant or feed water treating company can recommend the better m,ethod, de­pending upon circumstances in a particular in­stallation. Section VII of the ASME Code also contains information relating to laying up a boiler.

3-7

Chapter 3 - Maintenance

When shutting down, the pressure should be reduced gradually, and the pressure vessel cooled at a rate that avoids damaging temperature d5f­ferential that can cause harmful stresses. A vessel should not normally be drained until all pressure is relieved -- again to prevent uneven contraction and -temperature differentials. Draining the unit too quickly may cause the baking of deposits that may be present on the heating surfaces. Some heat, however, may be desirable to dry out the in­terior of the boiler.

After proper cooling and draining, fluslJ. out the water side with a high pressure water hose. Re­move any scale or deposits from the water side surfaces and check for internal or external corro­sion and leakage.

DRY STORAGE

Dry storage is generally employed when the boiler will be out of service for some time or when freez­ing temperatures may occur. In this method,- the boiler must be thoroughly dried, since any moisture will cause corrosion. Both water side and fire side surfaces must be clean of all scale and deposits, soot, etc. Steps must be taken to elimi­nate moisture by placing moisture absorbing material, such as quick-lime or silica-gel, on trays inside the drums and furnace. These trays should not be completely filled with the material, so that the corrosive liquid gathered in them does not overflow onto the boiler surfaces. Refractories should be brushed clean and wash-coated. Fire side surfaces may be sprayed or coated with an anti-corrosive material. All openings to pressure vessel must be shut tightly. Feedwater and steam valves should be closed. Damper and vents should be closed to prevent air from reaching fire side sur­face. Periodic inspection must be made and the ab­sorption m$iterials renewed.

Care must be taken to remove all of the moisture absorbing material before any attempt is made to refill the boiler. Serious damage can result other­wise. As a precaution it is recoIIitnendedthat warning signs be conspicuously posted. These signs could be similar to the following;

3-8

IMPORT ANT -- MOISTURE ABSORP­TION MATERIAL HAS· BEEN PLACED IN THE WATERSIDE AND FURNACE AREAS OF THIS BOILER. THIS MA­TERIAL MUST BE REMOVED BEFORE ANY WATER IS PLACED IN BOILER AND BEFORE BURNER IS FIRED. INSPECT PERIODICALLY AND RE­PLACE WITH FRESH AND/OR REGENE­RATED MATERIALS.

WET STORAGE

Wet storage is generally used for a boiler held in standby condition or in a case where dry storage is not practical. The possibility of freezing tem­peratures must be considered. Care must be taken to protect metal surfaces. Variables preclude defi­nite recommendations, however, it is suggested that after the vessel is drained and cleaned that it be refilled to overflowing with treated water. If deaerated water is not available, the boiler should be fired to boil the water for a short period of time. Additional chemicals may be suggested by the water consultant to minimize corrosion. Internal water pressure should be maintained at greater than atmospheric pressure. Nitrogen is often used for this purpose. Fire side surfaces must be thoroughly cleaned and re­fractories should be wash-coated. It is advis­able, if feasible, to occasionally circulate the water to prevent stratification and to insure that fresh inhibitor is in contact with all the surfaces. If additional chemicals are added for this idle period, more frequent blowdowns may be re­quired when the boiler is returned to service to rapidly reduce the chemical composition to nor­mal operating levels.

During storage, steps should be taken to protect the exterior components from the possibility of rust or corrosion. These parts should be coated with a rust inhibitor and protected from moisture and condensation. Operating controls, regulators, valves, etc. should be drained and dried. Electri­cal equipment should likewise be protected. Keeping the control circuit energized may prevent condensation from forming in the control cabinet or on the flame safeguard control.

CHAPTER 4

PARTS ORDERING INSTRUCTIONS AND PARTS LIST FURNISH COMPLETE INFORMATION WHEN ORDERING PARTS - When ordering parts for your boiler, be sure to include on your order the boiler serial number shown on the name plate at­tached to the front head. Your order should state the Cleaver-Brooks part number and the name and description of the part required. State the quantity desired, and specify method of shipment. Indicate date material is required. If repair parts are required for accessory equipment, such as an electric motor, pump, etc., which may not be shown, be sure to give the complete name plate data from the item for which the parts are required.

WHERE TO ORDER PARTS - Repair or replace­ment parts should be ordered from your Cleaver­Brooks representative.

RETURNING PARTS FOR REPAIR - Parts to be repaired should be directed to your Cleaver-Brooks

representative. A purchase order or a letter authoriz­ing repairs and giving complete details should be mailed to your representative. Prior to returning, please remove fittings or accessories from the com­poneqt, properly drain and clean part to comply with shipping regulations and include jnside of the package a packing slip identifying the part with your company's name.

If you desire to return parts for reasons other than repair or exchange, please contact your representa­tive stating reasons for the return and await permis­sion and directions prior to returning the material.

Many controls and other components can be factory­rebuilt (FR) or have a trade-in value. These items are available on an exchange basis. Consult your Cleaver-Brooks representative.

Be sure to show the serial number of your unit on all parts orders and correspondence.

®

~roOK5

WATERTUBE BOILER

UNIT NO.

MODEL PRESSURE PSI _

DATE

HEATING SURFACE

BOILER SO. FT. _ WATERWALL SO. FT. _

CLEAVER-BROOKS DIVISION AOUA·CHEM. INC.

MILWAUKEE. WISCONSIN U.S.A.

IT IS R,ECOMMENDED THAT YOUR LOCAL CLEAVER-BROOKS REPRESENTATIVE BE CONTACTED FOR PROMPT SUPPLY OF REPLACEMENT PARTS.

CLEAVER-BROOKS

4-1

Chapter 4-Parts List

Part No.

853-798 851-213 853-711 873-96 943-259 67-241 67-242 67-243 67-201 67-247 825-142 825-140 880-100 880-104 880-106

4-2

PARTS LIST

Req. Description

4 Gasket, Manway, 12" x 16" 1 Gage Glass, 3/4" x 18-1/4" 2 Gasket, 3/4", Gage Glass 5 Fitting, Water Column Electrode 1 Wrench, Water Column Electrode 1 Electrode, Water Column, 1/4" x 5-5/8" 1 Electrode, Water Column, 1/4" x 15-5/8'" 3 Electrode, Water Column, 1/4" x 18-3/8" , 1 Electrode, Water Column, 1/4" x 6-1/8" 1 Electrode, Water Column, 1/4" x 13-1/8" 1 Valve Set, Gage Glass 3 Trycock 2 Lens Kit, Blue - Observation Port 2 Lens Kit, Clear - Observation Port 2 Nut, Bakelite - Observation Port

NOTE: The above are standard replacement parts. Refer to the Burner Manual for additional parts.

MODEL "A" BURNER

MODEL "BR" BURNER

MODEL "CN" BURNER

Part No. 750-311

Part No. 750-305

Part No. 750-308