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LNGVehicle Fuel Tank SystemLiquid Natural Gas — The Clean Fuel for Today and Tomorrow
A Chart Industries Company
O P E R A T I O N S M A N U A L
1
SAFETY
Vehicle Tank Fuel Station
Customer Service: Customer Service:
Phone: 770-720-6770 Phone: 952-882-5204Fax: 770-479-6539 Fax: 952-882-5080
Web site: www.nexgenfueling.com
This manual deals with LNG vehicular fuel tanks,the hazards, and the safety precautions that arenecessary when working with this type of equip-ment. The manual is designed to familiarizeexperienced mechanics and vehicle operatorswith the features, safety precautions, operatingprocedures and maintenance of the LNG Fuel Sys-tem provided by NexGen Fueling. For moregeneralized information on LNG fuel systems referto NFPA 57 and 59A available from the NationalFire Protection Association, www.nfpa.org, 617-770-3000. For information on handling cryogenicliquids Refer to CGA P-12 available from the Com-pressed Gas Association, www.cganet.com,703-788-2700.
No attempt should be made to fill or maintain thisequipment until this manual and its supplementshave been read and fully understood.
Throughout this manual items appearing in
Bold Text highlight conditions that can result
in serious injury or death.
Table of Contents
Section Description Page No.
Safety 1
I Introduction 2
II Plumbing Components 3-4
III Accessories 5-6
IV Installation 7-10
V Fueling 11-12
VI Troubleshooting 13-16
VII Component Replacement 17-18
VIII Parts List 19-21
IX Appendix 22-25
X Warranty 26
Hazards of LNG
LNG is predominately methane gas. It is cooled to very lowtemperatures (less than minus 200° F) and stored as a cryo-genic liquid under pressure (up to 230 psig). Working withthe equipment can expose you to the following hazards.
Flammable Gas: Although the liquid is not flammable itrapidly evaporates in air into large volumes of gas. Thegas expands to 600 times its original liquid volume. Soeven small liquid leaks can pose a large fire hazard nearthe leak. The gas is flammable in concentrations ofbetween 5% and 15% in air.
Cryogenic Temperatures: The liquid LNG is belowminus 200° F. Since this liquid is stored under pressureyou can be cryogenically burned very easily by com-ing in contact with a pressurized liquid stream. You canalso be cryogenically burned by hard contact with acryogenic temperature fuel line.
Large Expansion Ratio: Since LNG will expand to 600times its original volume when warmed from a cryo-genic liquid to a room temperature gas it will buildextremely high pressures (over 3000 psig) if trapped inlines. Pressures this high will cause lines and fittings tofail. Care must be taken in the design of piping systemsand during maintenance operations to assure that liq-uid cannot become trapped between two valves.
Inert Gas: Although natural gas is non-toxic it is an inertgas and can cause asphyxiation if present in very largeconcentrations. This is a minimal hazard with vehicle fuelsystems as they simply don’t contain enough product todisplace large quantities of oxygen around the vehicle.
Safety Precautions
Keep the equipment area well ventilated. This will preventthe buildup of methane gas if leaks are present.
Cover eyes and exposed skin when working on LNG systems.
Isolate the fuel tank and remove the pressure from thesystem prior to maintenance operations.
Keep equipment away from open flames, sparks, andtemperatures over Ò1200° F.
Utilize leak detection equipment to locate small leaks.
A Chart Industries Company
2
INTRODUCTION I
Congratulations !!
You have just purchased the worlds most advancedLNG vehicle fuel tank. Despite its high tech appear-ance you will find it easy to use and maintain. It willgive years of trouble free service and is designed tooutlive the vehicles on which it is installed.
Cryogenics
The LNG fuel tank is a cryogenic container. This meansthat it stores the natural gas fuel as a highly refrigerat-ed liquid at low pressure. Typically the fueltemperature is about –220° F, and the fuel pressure isabout 70 psig. The reason for cryogenic storage is thatnatural gas is much more dense as a low temperatureliquid than it is as a compressed gas. Typically you canget three times as much gas in the same space atabout half the weight if it is stored as a cryogenic liq-uid instead of as a compressed gas.
The Storage Tank
To contain this cryogenic fuel without the use of anyoutside source of refrigeration the tank has to beextremely well insulated. To achieve the high level ofinsulation efficiency needed the LNG pressure vesselis covered with insulation and enclosed by an outervacuum vessel. A vacuum is pulled between the LNGtank and the outer shell. This combination of insula-tion and vacuum, called super-insulation, has thehighest thermal efficiency known with an R valueexceeding 5000. This type of insulation allows forstandby times of over a week with no loss of product.
Both the inner pressure vessel and the outer vacu-um vessel are constructed of stainless steel. Stainlesshas both the low temperature strength necessary tocontain the cryogenic fuel and the high temperaturetoughness to allow the vacuum casing to armor theinner pressure vessel. With an all stainless vesselsupport structure as well, the LNG fuel tank can with-stand years of vehicular service with no loss ofperformance.
Fuel Delivery System
The driving force for delivery of the fuel to theengine is provided by the fuel pressure itself, thereare no pumps in the system. When the enginedemands fuel the pressurized liquid natural gasflows out of the tank toward the engine. The coldpressurized fuel then passes through a HeatExchanger. The Heat Exchanger uses enginecoolant to vaporize the liquid and turn it into a gas.Once out of the Heat Exchanger the fuel is a warmgas, at tank pressure, ready to be burned by theengine. Tank pressure is maintained by a tankmounted Pressure Control Regulator that ventsexcess pressure into the fuel line during periods ofengine operation.
Relief Valves
Vapor Shutoff Valve
Super Insulation
Inner Vessel
Outer VacuumJacket
Evacuation Port
Excess Flow Valve
Fuel Shutoff Valve
Fill Check Valve
Pressure Control Regulator
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PLUMBING COMPONENTSII
Fill Check Valve
The fill line check valve is a bronze swing check with asoft seat. Its function is to prevent backflow throughthe fill line in the event of a fuel coupler failure orvehicle accident. It relies on tank pressure to seal anddespite the soft seat should not be regarded as a pos-itive shutoff valve. The Fill Check Valve connects to atop fill line inside of the tank.
Fuel Shutoff Valve
The Fuel Shutoff Valve (Liquid Valve) is a bronze globevalve with a soft seat. Its function is to provide a positiveshutoff of the fuel line for service and maintenance opera-tions. The fuel shutoff valve connects to the liquidwithdrawal line at the bottom of the tank and to the vaporwithdrawal line at the top of the tank through the Pres-sure Control Regulator. The fuel shutoff valve is open fornormal vehicle operation.
Excess Flow Valve
The Excess Flow Valve is a specialized check valvewith a hard metal seat designed to cut off fuel flow ifit exceeds a certain limit. Its function is to protect thefuel line between the tank and Heat Exchanger againstuncontrolled fuel release in the event of a vehicle acci-dent. It is not designed to protect piping downstreamof the Heat Exchanger, this is the function of the Auto-matic Fuel Shutoff Valve. The Excess Flow Valve is nota positive shutoff valve. Its hard seat allows a smallflow to pass by to allow the valve to automaticallyreset when the Fuel Shutoff Valve is closed.
Vapor Shutoff Valve
The Vapor Shutoff Valve (Vent Valve) is a bronze globevalve with a soft seat. Its function is to provide a positiveshutoff of the vapor withdrawal line for service and main-tenance operations. The valve connects to the vaporwithdrawal line at the top of the tank. The Vapor ShutoffValve is closed for normal vehicle operation.
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1012
Headring Tank
(Bus Style)
Shrouded Tank
(Truck Style)
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PLUMBING COMPONENTS II
Pressure Control Regulator
The Pressure Control Regulator (Economizer) is abronze pressure reducing valve that is open at pres-sures above its setpoint and closed at pressuresbelow its setpoint. Its function is to allow vapor toflow into the fuel line during vehicle operation toreduce the tank pressure to its setpoint. It is assistedin its operation by an Internal Check Valve in the fuelpickup line providing a 2 psi bias pressure to aidevapor flow. The setpoint of the regulator is non-adjustable being set at the time of manufacture. Flowthrough the regulator is not directional, it will be anopen valve whenever the fuel line pressure is aboveits setpoint.
Primary Relief Valve
The Primary Relief Valve is a brass cryogenic reliefvalve set at the maximum allowable working pressure(MAWP) of the tank. Its function is to vent product toatmosphere if the tank pressure exceeds the MAWP. Itis connected to the top fill line thereby providing addi-tional safety against over pressurizing the tank duringfilling operations. The Primary Relief Valve is equippedwith a pipeaway adapter to permit piping the ventgasses to a safe location on the vehicle.
Secondary Relief Valve
The Secondary Relief Valve is a brass cryogenic reliefvalve set at 1.5 times the maximum allowable work-ing pressure of the tank. Its function is to ventproduct to atmosphere to prevent a catastrophic fail-ure of the tank in the event of a malfunction of thePrimary Relief Valve or line. It is connected to thevapor withdrawal line providing a secondary reliefpath to the tank. It is protected from debris by a redvinyl cap and should never be piped away. Since thisis the last line of defense for the tank if the red vinyl
cap is ever missing the vehicle should be immediate-
ly removed from service and the primary relief
system inspected.
Evacuation Port
The Evacuation Port is located on the non-plumbinghead of the tank. Its function is to provide a re-seal-able connection for evacuating the tank. Its secondaryfunction is to provide a pressure reliefpath in the event of a product leak in thevacuum space. Do not remove the plug,not only will it cause the tank to losevacuum, but it will void your warrantyas well.
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11 13Top FillLine
Gas To Engine
To VentStack
Vapor Line
LNG Piping Schematic
Fuel Pickup Line
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ACCESSORIESIII
Fuel Contents Gage
Each LNG fuel tank comes equipped with an elec-tronic Fuel Contents Gage. The gage consists of twoparts: the fuel gage sender and a dash mount fuelgage. The fuel gage sender comes mounted to thefuel tank. Its function is to convert the electronic sig-nal from the internal fuel level probe to a signalcompatible with the dash mount gage. It is a solidstate, sealed unit and no field adjustments are possi-ble. The sender accurately reflects the actual mass ofthe product in the tank and is unaffected by productstate, pressure or temperature. It is designed todampen the effects of acceleration, braking, corner-ing and hills, although some variation will be seenon the gage under these transient conditions, similarto its gasoline or diesel counterpart. The fuel gage isa standard automotive type gage calibrated to thesender. It reads out empty to full and has an accura-cy of ± 1/16th of a tank. Note: The gage, the senderand the cable connecting the sender to the fuel tankare calibrated as a system and must be replaced withidentical parts to maintain gage accuracy.
Heat Exchanger
Every LNG fuel system must contain a Heat Exchanger.The function of the Heat Exchanger is to vaporize thecryogenic liquid fuel and deliver it as a warm gas tothe engine. The HeatExchanger is mount-ed in the fuel linenear the LNG tank. Itgets its heat fromthe engine coolingsystem and con-nects to the engineswater jacket throughflexible coolant lines.Note: The Heat Exchanger does not affect the fuelpressure it simply raises its temperature and turnsthe fuel from a liquid into a gas.
Fill Fitting
Every fuel system must contain a cryogenic fill con-nection. The function of the fill connection is toprovide a connecting point to the re-fueling stationthat permits a cryogenic pressure transfer to occur.The Fill Fitting incorporates a positive shutoff deviceto prevent fuel leakage when disconnected. Each fuelconnection needs to be mounted to the vehicle at alocation capable of withstanding a 250 pound load.This is necessary to assure that in the event of a dri-veaway the breakaway devices on the fuel station willfail first. Each fuel fitting should be fitted with a dustcap to prevent the introduction of water or debris intothe fuel tank.
Automatic Fuel Shutoff Valve
Every LNG fuel system must contain an AutomaticFuel Shutoff Valve. Its function is to shut off the fuelflow to the engine when the ignition is switched off orwhen activated by an out of limits sensor. Its recom-mended mounting location is at the warm gas outletof the Heat Exchanger, thisenables a wide selection ofvalves to be used. If a cryo-genic valve is used it can bemounted directly to the liq-uid shutoff valve in place ofthe Excess Flow Valve, thisconfiguration is not recom-mended as it requires theuse of a relief valve in thefuel line.
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ACCESSORIES III
Tank Pressure Gage
Standard on shrouded tanks, an optional mechanicalpressure gage can be mounted to any LNG fuel tank.A 1/4” pipe size pressuregage port is located on thePrimary Relief Valve tee atthe 12 o’clock position on theplumbing manifold to allowfor direct or remote mount-ing of a Tank Pressure Gage.
Overpressure Regulator
Some natural gas engines are unable to accept pres-sures up to the MAWP of the fuel tank. The fuelsystems on these engines needs to be equipped withan Overpressure Regulator to keep the operatingpressure window within acceptable limits for theengine. The Overpressure Regulator is mounted inengine fuel line downstream of the Heat Exchangerand Automatic Shutoff Valve. It works in conjunctionwith the Pressure Control Regulator on the fuel tankto establish the fuel systems operating pressure win-dow. The Pressure Control Regulator on the tank isset to the normal operating pressure of the engine.The Overpressure Regulator in the fuel line is set tothe maximum operatingpressure of the engine.The settings on these tworegulators assure that theengine will always seepressures within its oper-ating range. Note: If anOverpressure Regulator isused it must be set at least25 psig above the Pres-sure Control Regulator onthe tank to avoid transientlow pressure spikes onacceleration.
Vent Connector
Some refueling stations either require or have provi-sion for venting the tank during re-fueling. Vehiclesoperating at these stations should be equipped withVent Connectors compatible with the fuel stationsdesign. The Vent Connector is piped to the VaporShutoff Valve on the LNG tank. By connecting the sta-tion to the Vent Connector and opening the VaporShutoff Valve thetank pressure canbe vented to itsdesired location atthe fuel station.Note: Dependingon the design ofthe Vent Connectorand vehicle pipinga relief valve maybe necessary in the vent line to prevent liquid frombecoming trapped between the Vapor Shutoff Valveand the Vent Connector.
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INSTALLATION – MaterialsIV
Many materials are unaffected by cryogenic temper-atures. In general 300 series stainless steel, copperand brass, aluminum, fiberglass, wood, polyethylene,polypropylene, teflon and epoxies can be safely used.Carbon steel, 400 series stainless steel, zinc, PVC, andrubber become brittle at low temperatures and willfail if flexed while cold. When running low tempera-ture piping care should be taken in its mounting tostand it off of the vehicle frame, electrical wiring, andbrake or air lines that can embrittle and fail. Somepaints, notably enamels, tend to de-bond and flake offat cryogenic temperatures.
Piping
All piping material must be able to withstand theeffects of low temperatures without failure. On fuellines that carry LNG liquid we recommend the use ofrigid 300 series stainless steel tubing. Fill and fillcrossover lines may be rigid or flexible metallic ornon-metallic tubing rated for cryogenic service. Ventand relief pipeaway lines may be constructed out offlexible tubing or hose suitable for natural gas serv-ice. Since liquid and vent lines repeatedly go fromambient to cryogenic temperature allowances forthermal expansion must be designed into the pipingsystem. This is typically accomplished by incorporat-ing S bends or expansion loops into rigid lines. Ingeneral if one end of the tube can be moved 1/2" byhand while the other end is fixed it is flexible enoughfor low temperature service. If the tube is rigid it mustbe redesigned since it will move when it gets coldeasily pulling itself from supports and fittings.
Tube Fittings
Rigid tube fittings should be either a double ferruletype (Parker A-lok, Swagelok, or equivalent) or 3 piece37° flare type (Parker Triple Lock or equivalent). Tub-ing wall thicknesses used should be per fittingmanufacturers specification for gas service.
Pipe Threads
All pipe fittings should be installed using threadsealants. After the sealant is applied to the fitting itshould only be tightened in the clockwise direction toits final position. If the fitting is tightened past its desiredposition do not turn it counterclockwise to reposition.
Remove the fitting clean both surfaces and start over.Turning a pipe thread counterclockwise will cause
tiny thread leaks to develop over time. If multiple pipefittings are stacked up be sure to use two wrenchesto keep the back fitting from breaking loose. There aremany types of commercial pipe fittings available. Nex-gen recommends the use of NPTF fittings for leakresistance. When stainless fittings are used we rec-ommend the use of stainless to brass fittings toprevent galling during installation. When maintenanceis performed replace the brass fittings with new. Theuse of stainless to stainless pipe threads is not rec-ommended as severe galling during installationmakes achieving leak tight fittings nearly impossible.If maintenance is required it is difficult, if notimpossible, to get the fittings apart without destroy-ing the threads. If stainless to stainless threads mustbe used be sure to use a pipe sealant with anti gallingcompounds incorporated into it.
Pipe Sealants
For small threads (less than 1/2” pipe size) anaerobicsealants like Loctite 569 are recommended. For fit-tings 1/2” pipe size and over use an anaerobic sealantwith a teflon lubricant such as Loctite PST 567. Whenusing anaerobic sealants on stainless steel the fittingmust first be primed with an activator for the sealantto cure. A typical activator is Loctite Kleen-N-Prime.All anaerobic sealants have a cure time before pres-sure can be applied, the primers shorten these times.PST on brass requires 3 days to cure (4 hoursprimered), 567 requires 1 day (30 minutes primered).When applying anaerobic sealants apply a smallamount to the male thread 2 threads up from the end.Do not allow the sealant to run into the piping sys-tem as it will seal up valves and regulators as well asfittings. The use of thread tapes is not recommendedas tape filaments from maintenance operations caninterfere with regulators, relief valves, and enginecomponents.
Pipe Support
Piping and tubing should be supported along itslength to guard against vibration. A general guide-line is one support per two feet of tubing. A practicaltest is to “strum” the installed tube by hand. If itvibrates it is not supported well enough. Stainless Pclamps, and polyethylene or polypropylene tubeclamps are commonly used on cold lines. Care mustbe taken in support placement to allow for thermalexpansion and contraction of the lines.
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INSTALLATION – Components IV
Vehicle Tank
Since the fuel pickup is located near the plumbinghead the vehicle tank should be installed with theplumbing head of the tank facing the rear of the vehi-cle. Rear facing mounting assures that at low fuellevels that the fuel pickup will remain submerged dur-ing acceleration or when climbing hills.
The tank should be secured to the chassis with twosteel straps located just inboard of the head to shellwelds. The straps should incorporate rubber pads toprevent rotation or slippage of the installed tank. Inaccordance with NFPA 57 guidelines the mountingsystem should be sufficiently strong to hold 8 timesthe full weight of the tank.
Heat Exchanger
To assure proper Excess Flow Valve function the HeatExchanger should be mounted within 8 feet of thetank. The LNG inlet to the Heat Exchanger is piped tothe tank using rigid 300 series stainless steel tubing. Ifthe Heat Exchanger is less than 3 feet from the tank3/8” od x .035 wall tubing can be used. If greater than3 feet 1/2” od x .049 wall tubing is used.
The recommended coolant flow to the Heat Exchang-er is 1 gallon per minute of 180 F° coolant per 50horsepower engine output. For coolant lines less than10 feet in length this flowrate can be achieved using5/8” heater hose. For runs longer than 10 feet use 3/4”heater hose.
The Heat Exchanger should be piped so that the LNGinlet and the coolant inlet are on the same side. It canbe mounted either vertically or horizontally. To pre-vent air from becoming trapped in the coolant sideof the Heat Exchanger the coolant ports must bepointed up in horizontal mounts, the gas out andcoolant out ports must be up on vertical mounts.
Note: The if the Heat Exchanger is installed in serieswith the cab heater the coolant piping must allowcoolant to flow even when the cab heater is turned off.
Automatic Fuel Shutoff Valve
To minimize the flow restriction to the engine theAutomatic Fuel Shutoff Valve should have a mini-mum Cv of 2.0. It should be mounted to the warmgas outlet of the Heat Exchanger. Even though thevalve is screwed directly into the Heat Exchanger itsweight should be supported by a mounting bracket.The valve should close when the vehicles ignitionswitch is placed in the off position. It also may beactivated by out of limits sensors on the engine orfuel system. Nexgen recommends the inclusion of alow temperature limit switch on the warm gas lineto protect the valve and downstream components inthe event of a cooling system malfunction.
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INSTALLATION – ComponentsIV
Primary Relief Valve Vent Stack
The Primary Relief Valve should be piped to a safepoint on the vehicle. Since methane gas rises it is typ-ically piped to a vent stack that exhausts at the top ofthe vehicle with flow directed upwards. Since thereis a possibility of relieving liquid through this line itsdischarge path should be away from persons, igni-tion sources or materials that could be damaged byexposure to cryogenic temperatures. To prevent thepossibility of water accumulating and freezing in therelief valve line the vent stack should include provi-sions for excluding rain and wash water from the lineand incorporate a low point water drain. The mini-mum recommended size for vent stack is 1/2” tubing.
The tubing connecting the Primary Relief Valvepipeaway to the vent stack can be either metallic ornon-metallic tubing suitable for low temperaturemethane service. The minimum tubing size is 1/2”.
Fill Line
Many vehicles have remote mounted fill connectionsand require a fill line to connect to the fuel tank. Sincethe fill line is handling high pressure, high flow cryo-genic liquid NexGen recommends metallic tubing beused. The minimum fill line size depends on the tanksize and fill connector, but it generally would be 1/2”tubing for tanks less than 50 gallons and 3/4” tubing fortanks larger than 50 gallons. If rigid tubing is used itshould incorporate at least one S bend between thefill connector and the fuel tank to allow for flexibilityand collapsibility in the event of a vehicle accident.
Engine Fuel Line
The fuel line from the Automatic Shutoff Valve to theengine can be either metallic or non-metallic tubingsuitable for natural gas service. If non metallic tubingis used a low temperature shutoff switch must be incor-porated into the fuel system. The engine fuel lineshould be, at a minimum, 1/8" larger in diameter thanthe LNG liquid line into the Heat Exchanger to prevent aflow restriction as the fuel expands when it is vaporized.
Fuel Contents Gage
The Fuel Contents Gage consists of two parts: thesender and the gage. The sender is a sealed unit thatcomes mounted to the fuel tank. It is connected tothe vehicle via a 3 pin female Weatherpak connector.The pins are power (red) A, signal (green) B, andground (black) C. The sender should be protectedwith a 1 amp fast blow automotive type fuse. Thegage is a standard automotive type fuel gage andshould be mounted on the dashboard inside of thevehicle. The power, signal and ground wires shouldbe common to the sender for proper gage function.
Gage Wiring Schematic
Pin BGreen
Pin CBlack
Pin ARed
1A
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+ S
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Gage
Sender
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INSTALLATION – Multiple Tanks IVWhen available space on the vehicle won’t accom-modate the vehicles fuel requirement in a single tankit is easy to manifold multiple tanks together. The fill,liquid, vent , relief valve, and gage lines are simplyconnected in parallel in accordance with the followingrecommendations. The tanks will fill and supply prod-uct independently of one another, but act as a system,appearing to the engine as a single large tank. Note:During refueling it is common for the tanks to go fullat different times. This causes the flow and pressureto change several times during multiple tank fills. Themultiple pressure spikes can confuse the automaticshutoff system in some fuel stations into shuttingdown before all of the tanks are completely filled.Therefore NexGen does not recommend multipletank systems of more than three tanks per vehicle.
Fill Crossover Line
The fill line size requirement is the same as a singletank systems. To achieve reasonable fill times use3/4” (min) line size for tanks whose aggregate capac-ity exceeds 50 gallons, 1/2” (min) line size can be usedon tanks whose aggregate capacity is less than 50gallons. On groups of tanks that are mounted sideby side a fill manifold is generally the easiest solu-tion to multiple tank fill lines.
Fuel Line
The fuel lines to the engine are simply teed togetherbefore they enter the Heat Exchanger. Line sizes arethe same as in single tank installations to assureproper Excess Flow Valve function. Note: Since thefuel lines are common to all of the tanks the fuel pres-sure will be the same in all tanks except immediatelyafter filling.
Relief Valve Lines
The Primary Relief Valve discharge lines may bepiped together into a single vent stack. 1/2” minimumtubing should be used.
Vapor Shutoff Valves
The Vapor Shutoff Valves (Vent Valves) can be pipedto a common connection, but they must haveCheck Valves placed in series with them onlyallowing flow out of the tanks. This will prevent de-pressurizing the system if the vent valves areaccidentally left open during vehicle operation.
Fuel Contents Gage
The Fuel Contents Gage can be configured to haveone gage read out the multiple tanks contents as if itwere a single tank. In this configuration a capacitancecable is run between the tanks and the sender simplysums the tanks contents and displays them on a singlegage. The connecting cable is part of the gage cali-bration and must be replaced with an identical part ifdamaged to assure proper gage operation. Alterna-tively each tank can have its own sender and displayits contents on a separate gage. Note: On multipletank systems the tanks fill and drain independentlyfrom one another. It is unusual, except after a fill, for allof the tanks to have the same liquid level. While it isinteresting to watch it has no effect on engine opera-tion, range or system re-fueling.
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Top FillLine
Vapor Line
Dual Tank Schematic
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Top FillLine
Gas To Engine
To Vent �Stack
Vapor Line
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Fuel Pickup LineFuel Pickup Line
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FUELINGV
Fuel Station Requirements
Your LNG fuel tank is designed to be filled from anyLNG fuel source. The only requirements on the sta-tion are filtration and delivery pressure. Since LNG,like any liquid fuel, can pick up and transport debristhat can cause fuel system problems a 100 micron orfiner fuel filter is mandatory on all fuel station filllines. The LNG fuel tank has a 230 psig Primary ReliefValve on its inlet line therefore the delivery pressureof the fuel station should be 225 psig or less.
Normal Fueling
The LNG fuel tank is designed to be top filled througha single fill hose with no vent return. This is accom-plished by spraying subcooled LNG into the vaporspace of the tank. The cold liquid condenses thevapor and creates space for itself inside of the tankeliminating the need to vent product. Since this willresult in a 100% fill a small tank (ullage tank) insideof the main tank guards against overfilling.
A typical fill sequence would involve connecting thefill hose to the tanks fill coupler. Open the stations fillvalve and monitor the flow or line pressure as the fillprogresses. Initially at the start of the fill there is a briefpressure spike as the fill piping cools down. The flowand pressure then remain stable during the remainderof the fill. When the tank becomes full the pressurerapidly spikes up to the station’s delivery pressure andthe flow rate falls off dramatically. The reason the flowdoesn’t immediately go to zero is because of theullage tank. The ullage tank has a small opening (rel-ative to the main fill line). Once the main tank goesfull there will still be a small flow (typically 1-2 gpm)into the ullage tank. When the rapid pressure rise orflow drop is observed the tank is full and the station fillvalve should be shut. Even though it is still possibleto put more liquid into the tank by continuing to fill theullage tank, the ullage tank is there to allow for fuelexpansion and standby time. If the ullage tank is com-pletely filled the hold time will be zero and the PrimaryRelief Valve will open almost immediately after the fill.If the fill is stopped at the onset of the rapid pressurerise/ flow decay, when the ullage tank is empty, thetank will have about a week of standby time even if thevehicle isn’t driven. Most permanent fuel stationsautomatically monitor and perform these functions sothe fueler’s only duty is to connect and disconnect thefuel hose and push the Start button.
Vent Filling
Although the preferred method of fueling is via a sin-gle hose top fill it is possible to vent fill the tank. Thisprocedure is usually used when pressure transferringfuel out of a temporary fueling facility or portable fueltank. Since this normally is a manual procedure itrequires more operator knowledge of the system. Ifthe product is vented to atmosphere it should bedirected to a vent stack discharging to a safe location.The vehicle tank must be vented slowly if it is aboveits normal operating pressure so that liquid isn’tdrawn out of the Pressure Control Regulator into thevent gas stream. Care must also be taken to monitorvehicle tank pressure during a fill so that at the end ofthe fill it arrives at its normal operating pressure.
Vent Filling from a Station with a P/B
When Vent Filling from fuel station with a pressurebuilding system the LNG in the station should be sat-urated to within 10 psig of the vehicle tanks PressureControl Regulator setting (vehicle operating pressure).The fuel station should be pressurized to at least 50psig above the vehicle operating pressure. The vehiclefuel tank’s pressure should be vented to 20 psig belowthe vehicle operating pressure. Connect the fill linefrom the station. Open the station’s fill valve and thevehicles Vapor Shutoff Valve. Once liquid starts flow-
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FUELING V
ing into the vehicle tank close the Vapor Shutoff Valve.Filling should now proceed much like a single hose fill.Once the flow stops or the pressure on the vehicletank rapidly rises shut off the station’s fill valve. Con-firm the tank is full using the Fuel Contents Gage onthe dash. If the filling tank loses pressure before thevehicle tank is completely filled, vent the vehicle tankpressure down, this time only to the vehicle operat-ing pressure, allow the filling tank to re-pressurize andrepeat the process.
Vent Filling from a High Saturation Source
If the fuel station’s saturation pressure is above thevehicle operating pressure and the station has no pres-sure building system a vent fill should be performed asfollows. Vent the vehicle tank down to 30 psig belowthe vehicle tanks Pressure Control Regulator setting(vehicle operating pressure). Connect the fill line fromthe station. Open the station’s fill valve and the vehiclesVapor Shutoff Valve. Throttle the vehicle tank’s VaporShutoff Valve (and station’s fill valve if necessary) dur-ing the fill to maintain the vehicle tank pressurebetween 10 and 20 psig below the vehicle operatingpressure during the fill. When the tank reaches 3/4 full,close the Vapor Shutoff Valve and continue filling untilthe pressures equalize and flow stops.
Fueling a Warm Tank
An LNG fuel tank that has been idle for a long periodof time, still has fuel, and is at its relief valve pres-sure is considered to be a warm tank. This tank mustbe vented down below the fuel station delivery pres-sure prior to filling.
First Fill or Hot Tank Fill
An LNG tank when first installed is considered to bea hot tank. Hot tanks will build pressure rapidly duringthe fill as the pressure vessel cools down, on manystations this will prematurely stop the fill. The rec-ommended first fill procedure is to put 5-10 gallons ofLNG into the tank. Check the plumbing for leaks.Drive the vehicle for 10–15 minutes, this will pull thepressure down to normal and cool down the tank. Re-check for leaks and fill normally. This same procedureis recommended for tanks that have been empty andout of service for more than ten days. Alternativelyput 5-10 gallons of LNG into the tank and fuel like awarm tank.
13
TROUBLESHOOTING – ComponentsVI
Rapid Pressure Rise
There are three main causes of rapid pressure rise onLNG fuel systems. They are overfilling, fuel systemleaks or malfunctions and loss of vacuum. A properlyfunctioning, properly filled LNG fuel system shouldbuild less than 15 psig per day. Any system that buildsmore than 40 psig per day needs troubleshooting todiscover the cause.
Overfilling
If the fuel tank is overfilled there will be little or nospace for the fuel to expand as it picks up heatthrough the insulation. The most common cause ofoverfilling is not shutting off a single hose fill atthe onset of the rapid pressure rise at the end of afill. (See Fueling Section)
Fuel System Leaks
Since LNG has such a large expansion ratio pipingleaks can cause pressure rise if they draw liquidinto the external lines. If the vehicle has not beenoperated for a few hours (and the outside temper-ature is above freezing) all external plumbing linesshould thaw out. If a line remains frozen trou-bleshoot the piping to determine the cause.
Vacuum Loss
Total loss of vacuum is an unusual event for anLNG tank (resulting in frosting of the entire outershell), however the vacuum will slowly decay withtime as gasses diffuse out of the tank materials.This will show up over time as more and morerapid pressure rise times, eventually exceeding 40psi/day. Once the vacuum has decayed to this pointthe tank will need to be re-evacuated by a compe-tent maintenance facility. While the rate of decayvaries with tank service conditions (higher pressuretanks vacuum decays faster) the vacuum lifeshould exceed the engine life of the vehicle. It isrecommended that at engine overhaul or replace-ment that the fuel tank be re-evacuated.
Pressure Rise Test
To establish the pressure rise of an LNG fuel systemthe following test should be performed. Fill the tankto between 1/2 and 3/4 full. Drive the vehicle for about10 minutes. Park the vehicle. After 15 minutes recordthe tank pressure. After a prescribed period of time
(at least 8 hours) record the pressure again. Check tosee that the plumbing is thawed, if so this is the pres-sure rise for the fuel system.
Fuel Contents Gaging System
Problems with the fuel contents gauging system canbe easily diagnosed by the use of the Fuel SystemTester (P/N 11656419). The tester enables diagnosis ofboth tank side and vehicle side problems with thegage circuit.
The Fuel System Tester plugs into the Weatherpakconnector between the fuel gage sender and vehiclewiring harness. It gets it’s power from the vehicleitself. To use the tester simply connect the Weather-pak plugs, turn on the power to the gage circuit andread the lights on the front panel. If the gage circuitis functioning properly all three green lights will belit and the fuel gage will read 1/4 full. Fault conditionson the fuel tank or with thevehicle wiring will be dis-played on the tester. If anintermittent problem is pres-ent wiggle the wiringconnectors with the testerconnected, an open or short-ed connector will cause thefault lights to flash. The fueltank can be tested off of thevehicle. Simply connect thetester to the Weatherpakconnector on the tank andpush the test button on the top of the unit. On multitank systems both tanks need to be connected sincethe connecting cable is an active part of the circuit.
Debris in Components
Debris commonly enters the tank in two ways. It iscarried into the tank during refueling, from either dirtyfill connectors or unfiltered fuel, or parts that aren’tproperly cleaned prior to reassembly during mainte-nance operations. Either way the end result is thesame, the debris becomes lodged in a tank compo-nent and interferes with its function.
Debris In Relief Valves
Debris in the Primary Relief Valve will typicallylodge underneath the valve seat and cause the
14
TROUBLESHOOTING – Components VI
relief valve to remain open well below its 230 psigsetpoint. More commonly the cause of a reliefvalve staying open is water filling the dischargepiping due to inadequate shields and drains on thepipeaway line. If a relief valve is stuck open due towater contamination it can be quickly thawed bypouring water on the outside of the valve. If thevalve reseats when thawed the pipeaway drainsand shields should be inspected. If the valve doesnot reseat when thawed it will have to be replaced.
If the Primary Relief Valve becomes plugged withdebris the tanks pressure could rise above 230 psigup to the Secondary Relief Valve setting of 350psig. If tank pressures of over 250 psig are
observed or if the red vinyl cap is gone from the
Secondary Relief Valve the vehicle should be
immediately removed from service and the Prima-ry Relief Valve and pipeaway lines inspected todetermine the cause of failure.
Debris in Pressure Control Regulator
Typically debris in the Pressure Control Regulator(Economizer) will lodge underneath the regulatorseat holding the valve open below its setpoint. Ifthis happens the tank will gradually lose pressureduring operation. It can be diagnosed by observingthe regulator on the vehicle when it comes in fromits route. If the tank pressure is more than 10 psigbelow the Pressure Control Regulator setpoint, thetank still has fuel, and the regulator is frosted overit is stuck open due to debris. The first course ofaction to fix the problem would be to take the vehi-cle out of service and allow the fuel to warm and itspressure to rise to at least 30 psig above the Pres-sure Control Regulator setting. This will fully openthe valve and allow the debris to be carried out intothe fuel stream with use. Also since the debris maybe ice it will have time to melt and correct itself. Ifthe problem does not correct itself with use theregulator will have to be replaced.
On tanks that are heavily contaminated it is possibleto completely plug the Pressure Control Regulatorwith debris. In this case the tanks pressure will risein service and the regulator will not be frosted overduring use even though the tank pressure is aboveit’s setpoint. The regulator will have to be replacedto correct this problem.
Pressure Control Regulator Test Procedure
The Pressure Control Regulator and Internal CheckValve can be checked for proper function withoutremoving them from the tank utilizing the followingprocedure.
Vent the tank pressure to at least 25 psig below thePressure Control Regulator regulator setting. This inall cases should be less than 100 psig. Note: It is rec-ommended, but not imperative, to empty the LNGfrom the tank for this test.
Connect a nitrogen gas cylinder with an adjustablenon-relieving pressure regulator (0-150 psig) and a0-100 scfh flowmeter rated for at least 150 psig(Dwyer VFB-53 or eq.) to the outlet of the Excess FlowValve on the cylinder. Minimum line sizes should be1/4" to maintain adequate flow for the test. Do not use
air for this test. This will result in a flammable (explo-
sive) gas mixture inside the tank.
Open the Fuel Shutoff Valve on the tank. Adjust thenitrogen gas pressure until it is slightly (~5 psig)above the tank pressure and nitrogen gas begins toflow into the tank. The flow should be in the 10-20scfh range. If the flow pegs the meter either the Pres-sure Control Regulator is fully open or the internalcheck is open, generally the sound will reveal which.
Slowly increase the pressure, opening the PressureControl Regulator, until the flow rapidly increases to the60-80 scfh range. Decrease the pressure observing theflowmeter as you do. The point at which the flow stopsrapidly falling with decreasing pressure is the PressureControl Regulator setting. Never exceed 150 psig dur-ing this test or you could rupture the flowmeter.
Close the Fuel Shutoff Valve before you remove thetest equipment.
Nitrogen
Pressure Control
Regulator Test
15
TROUBLESHOOTING – LeaksVII
While none of us want leaks in our equipment anypressurized system with removable parts is subject totheir development. Preventative maintenance activi-ties on LNG fuel systems should include a program todetect and repair leaks.
Other than the economic impact of losing fuel, the pri-mary hazard of leaking natural gas is a flammabilityhazard. If the local gas concentration reaches 5% inair the gas mixture will be flammable. In order toreach this concentration the natural gas must leak outfaster than it can diffuse into the surrounding air. Thismeans that large leaks are more hazardous than aresmall leaks and that the hazards and maintenanceprogram can be classified by leak size.
Liquid Leaks
Liquid leaks are by definition hazardous. Even smallones release hundreds of times more gas than dogaseous leaks through the same size opening. Theyare always flammable. All liquid leaks should beimmediately repaired. They are the easiest type ofleak to detect since they are both visible and audiblerequiring no specialized equipment to find. The prin-cipal cause of liquid leaks are parts failures or poorinstallation techniques. Loose or cracked fittings andworn valve packings would be typical examples.
Gaseous Leaks
Gaseous leaks are by nature less hazardous than liq-uid leaks since they release less natural gas thanliquid leaks. The difficulty in dealing with smallgaseous leaks is that they are invisible, and requirespecial techniques and equipment to locate.
Audible Leaks
Gaseous leaks become audible, in a quiet environ-ment, at a flowrate of about 1 liter per minute (1000cc/min). Audible leaks are large leaks and always flam-mable. These leaks should be immediately repaired.They are caused, like their liquid counterparts, byloose or cracked fittings, worn valve packings andfailed seals.
Inaudible Leaks
Although all audible leaks are flammable it is not truethat all inaudible leaks are not. Because they areinaudible and invisible leak detection equipment must
be used to locate leaks smaller than 1 liter per minute.Most inaudible leaks are not the result of parts failures,but rather are the result of improper assembly tech-niques or small defects in parts. Leaks that spiralthrough a pipe thread, follow porosity through a cast-ing, or seep past a particle trapped in a compressionfitting are typical examples. These leaks typically don’tgrow larger with age and will generally show up in thefirst few hours of vehicle operation.
Ultrasonic Leaks
Even though we can’t hear leaks much smaller that 1liter / minute they are still making sound. The sound isin the ultrasonic frequency range and can be “heard”by the use of an ultrasonic leak detector. An ultra-sonic leak detector will rapidly find and pinpointleaks down to about 100 cc/min. Ultrasonic size leaks,while flamma-ble, pose littlethreat to mov-ing vehicles orto maintenancefacilities. Themain threat would be accumulation of gas in a poorlyventilated compartment while the vehicle is parked.They should be repaired when discovered.
Small Leaks (Bubble Testing)
Leaks smaller than 100 cc/min.are most easily pin-pointed via commercially available bubble testsolutions. It should be noted that this is not soap.Most soaps contain high levels of chlorine and sur-factants. While it is true that soap solutions will findthe leaks, like bubble test solutions, it is also true thatthey will cause leaks by breaking down sealants andcorroding fittings. Bubble testing will not only pin-point the source of small leaks, but it will also classifythem by size. One caution on the use of bubble testsolutions, leaks larger than 100 cc/min blow out thebubbles so fast and dry themselves out so quicklythat they might be missed in a piping check relyingonly on bubble testing. It is recommended that gen-eral leak surveys be done with an ultrasonic leakdetector or flammable gas detector then pinpointsmall leaks with bubble test solutions.
16
TROUBLESHOOTING – Leaks VII
Small Flammable Leaks
Leaks between 25 cc/min and 100 cc/min are flam-mable in still air. If ignited the flame ranges in sizefrom less than 1/16th of an inch tall, sustainable onlyin dead calm conditions to a flame the size of a nor-mal cigarette lighter flame. This size of leak ischaracterized by bubbles that grow and burst at thesite of the leak before they can flow away from it.These leaks pose no hazard in moving air, or in wellventilated compartments, but could accumulateinside of small, poorly ventilated enclosed spaces.These leaks are typically caused by poor pipingdesign or support that puts cyclic strain on the joints.
Non Flammable Leaks
Leaks smaller than 25 cc/min. are not flammable inair. They are characterized by a stream of bubbles thatgrow in size and foam off of the leak. Typically thebubbles range in size from 1/8” to 3/8” in diameter.The bubbles don’t burst at the site of the leak, ratherthey flow away from theleak and burst down-stream as they dry out. Ina ventilated environ-ment, even in still airthey pose no flammabili-ty hazard and are mainlyan economic nuisance.The largest leak in thisgroup, 25 cc/min., willcost about $5.00 per yearin lost product.
Insignificant Leaks (Diffusion)
Leaks smaller than 1/2 cc/min. are so small and dif-fuse so rapidly that they can be ignored. They arecharacterized by a series of uniform size tiny (smallerthan a pinhead) bubbles that emerge from the leak.This might show up immediately as a chain of tinybubbles on leaks nearthe 1/2 cc/min size orappear as foam aroundthe fitting up to 5 min-utes after the fitting issprayed with bubble testsolution for the smallestones. In either case theleaks are not flammableand will not accumulateinside of vehicle com-partments.
Flammable Gas Detectors
Handheld flammable gas detectors are available in awide variety of configurations and sensitivities. Thesensitive ones are good at detecting the presence ofminute quantities of flammable substances, but aredifficult to use to pinpoint the source. The less sensi-tive ones can more easily pinpoint leaks, but have tobe held quite close and are difficult to use aroundmost vehicle plumbing. They are useful for survey-ing for leaks, but not good at identifying the sources.
17
COMPONENT REPLACEMENTVII
BonnetAssembly
CopperGasket
Tank Mounted Components
Prior to starting any work on tank mounted plumb-ing components that cannot be isolated by closingthe Liquid Shutoff Valve or Vapor Shutoff Valve.
De-fuel the tank.
Release all pressure from the fuel tank.
Do not leave the tank open to air any longer than ittakes to replace the defective part.
Piping Components
For plumbing components that can be isolated fromthe tank by closing the Liquid Shutoff Valve or VaporShutoff Valve.
Close the liquid and Vapor Shutoff Valves.
Release all pressure from the plumbing lineunder maintenance.
General
When removing components use a backup wrench onpipe fittings so as not to disturb downstream plumbing.
Clean all traces of pipe sealants from pipe threads,this will require the use of a stainless steel wire brush.On female threads the sealant residue must be blownout of the fitting with nitrogen gas, this may requirepurging out the entire tank with nitrogen gas. Do not
use shop air to purge out LNG tanks this can resultin a flammable (explosive) gas mixture inside of thetank. Air also introduces large quantities of water intothe tank which can freeze and plug lines.
Replace brass pipe fittings with new, don’t attemptto reuse the old fittings.
Stainless steel pipe fittings must be primed with acti-vator prior to the use of thread sealant.
Allow sufficient time for the thread sealants to curebefore pressure testing the piping.
Pressure test the plumbing after all new parts instal-lations and re-check after a days service.
Pressure Relief Valves
The inner pressure vessel used in an LNG fuel tank isdesigned and rated for a maximum operating pres-sure. The maximum operating pressure for the vessel
is stamped on the data plate located on the plumb-ing end of each tank. Do not replace a relief valve with
a higher pressure one. Do not attempt to repair orreset a relief valve.
Product Isolation Valves
The Liquid and Vapor Shutoff Valves have spring loaded valve packings. This auto-matically compensates for thermal shrinkage and wear. If a valve packing does become damaged or wear out the valve stem assembly can be replaced as follows:
Fully open the Shut-off valve
Loosen and remove the Bonnet Assembly. (Thewhole assembly should unscrew out of the valvebody.)
Remove the old Copper Gasket and discard.
Adjust the valve seat on the new Bonnet Assem-bly until no threads can be seen protruding fromthe bonnet.
Place the new Copper Gasket onto the replace-ment Bonnet Assembly. Note: Due to thehorizontal alignment of the valve, care must betaken to properly align the Copper Gasketbetween the Bonnet and Body. The gasketshould protrude evenly from all sides of thebonnet’s wrench flats.
Thread in the new Bonnet Assembly and tightenit hand-tight. (It may be necessary to screw in theBonnet Assembly until it almost touches theCopper Gasket and then align the gasket with thegroove before hand-tightening the BonnetAssembly.
Tighten the Bonnet 1/8th turn from hand tight(~25 ft-lbf)
If the valve leaks, tighten the Bonnet another1/16th turn until leak stops.
Pressure Control Regulator Replacement
Since the Pressure Control Regulator regulator ismounted in the inverted position care must be takenduring its installation to prevent thread sealant fromflowing into and plugging the valve seat. To install theregulator first thread it two threads onto the stainlesspipe nipple on the tank. Apply a drop of thread sealantonto the joint and continue tightening normally.
Internal Check Valve Replacement
The internal check valve is located inside of theplumbing manifold on the tank, behind the elbowconnecting the manifold to the economizer U tube.The tank must be empty and purged with nitrogengas prior to starting this procedure. To remove thecheck valve remove the economizer U-tube and theelbow in the manifold. Insert the check valve wrenchinto the valve and unscrew. Flow nitrogen gas at ~20scfm through the tank and clean out the internal 1/8"pipe thread with a 7/16" diameter stainless steel wirebrush. Clean the pipe coupling on the manifold with a5/8" diameter stainless steel wire brush. Primer boththe internal thread and the 1/4" pipe coupling on themanifold with activator for the thread sealant using afine brush applicator. Install a new check valve usingthe check valve wrench. Install a new elbow, takingcare to stop at the proper orientation to mate withthe economizer U-tube. Re-install the U tube.
BNC Connector Replacement
This is the most difficult part on the tank to replacesince it has both pressure and electrical componentsin it. The tank must be empty and depressurized priorto starting this procedure. Toremove the connector put a lon-gitudinal cut in the encapsulatingheat shrink tubing encasing it.Heat the heat shrink with a heatgun to cause it to split awayfrom the fitting. Grab one end ofthe still hot tube with a pliersand peel it from the connector.Disconnect and inspect the maleconnector and sender wire fordamage or corrosion. Unscrewthe BNC connector from theelbow. Pull the wire out of the fit-ting. Clean the thread sealant out of the mating elbowwith a wire brush. Primer the replacement BNC con-nector with activator for the thread sealant. Make surethe garter band is installed around the female con-tact inside of the BNC connector. Apply thread sealant
18
COMPONENT REPLACEMENT VII
to the BNC connector. Push the wire into the connec-tor making sure it engages the internal pin by about3/8" after making contact with it. Once engaged itshould easily rotate on the pin. Screw the BNC con-nector into the elbow. Put a 4" piece of encapsulatingheat shrink over the sender wire and connect the BNChalves together. Heat the heat shrink until it uniform-ly shrinks onto the fitting and the encapsulating linermelts. Extra care must be taken to assure that theback side of the heat shrink gets heated and no voids,or lumps are present.
Fuel Gage Sender Replacement
This is a non-pressure component and can bereplaced without de-pressurizing the tank, howeverbefore using a heat gun around the plumbing shut offthe product isolation valves and check for leaks. Fol-low instructions for BNC Connector Replacement todisconnect the BNC cable. Inspect the BNC connec-tor on the tank for corrosion and for the presence ofthe garter band around the female contacts. Unlatchand pull apart the Weatherpak connector. Remove themounting clips and pry off the old sender. Scrape offremnants of the VHB tape adhesive. Peel off the back-ing from the VHB adhesive on the new sender andplace it on its mounting plate. Install the mountingclips with the hooks onto the plastic box and thesmooth side on the stainless plate. Reconnect theWeatherpak connector. Connect the BNC cable perthe instructions for BNC Connector Replacement.
BNC Connector
GarterBand P/N 11657737
Heat ShrinkTube P/N 11502575
19
Item Part Description
No. No.
1 11556768 Fill Check Valve 1/2" (Tanks > 50 gallons)11556733 Fill Check Valve 3/8" (Tanks < 50 gallons)
2 11673278 Fuel Shutoff Valve Rebuild Kit (Red Handle)3 11556741 Excess Flow Valve 3/8" Bronze
(Headring Tank)10614840 Excess Flow Valve 3/8" Stainless
(Shrouded Tank)4 11673251 Vapor Shutoff Valve Rebuild Kit
(Silver Handle)9715759 Rego Valve Rebuild Kit (Obsolete)
5 11055541 Pressure Control Regulator (Economizer)10524262 Internal Check Valve 2 psi
6 11208974 Primary Relief Valve (230 psi)7 11209011 Secondary Relief Valve (350 psi)
10645662 Red Vinyl Cap
8 11718341 Fuel Gage Sender 12 Volt Single Tank 30" Lead
11718309 Fuel Gage Sender 12 Volt Dual Tank 30" Lead
10923888 Fuel Contents Gage 12 Volt (Dash Mount 2-1/16")
10484900 BNC Connector Kit (Obsolete)11718552 New BNC Connector Kit10692071 Sender Mounting Clip Stainless10692101 Male Weatherpak Kit11055867 Fuel Gage Sender 12 Volts
15" Lead (Obsolete)
Item Part Description
No. No.
9 10682851 Heat Exchanger 150 Horsepower9722999 Heat Exchanger 300 Horsepower10668725 Heat Exchanger 450 Horsepower
10 11488232 Fill Fitting (Parker)10492678 Dustcap (Parker)10797447 Fill Fitting (JC Carter)11019170 Dustcap (JC Carter)10557574 Fill Fitting & Dustcap Tanks
< 50 Gallons (NexGen)11 10798239 Automatic Fuel Shutoff Valve 12 Volt 3/8"12 10624239 Tank Pressure Gage 300 psi 1/8"
10924101 Bushing 1/4" Male X 1/8" Female13 10644942 Overpressure Regulator 30-100 psi (Red)
10586834 Overpressure Regulator 100-200 psi (Brown)14 11674262 Vent Connector and Dustcap
(45 Flare Elbow 3/8")15 11548178 Vent Check Valve 3/8"16 11666414 Tee 1/4" Brass17 11359158 Street Elbow 1/4" Brass 18 1211102 Plug 1/4" Brass19 11708178 Hex Nipple 3/8" Stainless20 1210402 Elbow 1/4" Brass21 11646202 U Tube Assembly 37° Flare Copper
11502559 U Tube Assembly Stainless (Obsolete)22 1111632 37° Flare Elbow 1/4" Brass
Headring Tank
(Bus Style)
VIII
8
6
7
4
5
3
2
1
19
21
8
17
20
171618
22
PARTS LIST
20
Shrouded Tank
(Truck Style)
PARTS LIST VIII
35
28
8
26
2728
2930
313
32
25
33
12
10 34
37
38
36
Item Part Description
No. No.
25 11658975 Sender Mounting Bracket Stainless
2913921 Bolt 1/4-20 X 1-1/2" Stainless
2914071 Lock Nut 1/4-20 Stainless
26 2811726 Tube 1/2" OD Nylon
27 2710131 Tube 3/8" OD Stainless
28 1013356 Elbow 1/2" OD X 3/8" Male Nylon
29 1111602 37° Flare Connector 3/8" Brass
30 10888656 Bulkhead Connector 3/8" Brass
31 10502004 Compression Elbow 3/8" Stainless
32 10790982 45° Street Elbow 3/8" Brass
33a 11647862 Cover Plate Stainless - Single Tank
33b 11672742 Cover Plate Stainless - Dual Tank
33c 10923765 Cover Plate Stainless - Blank
11384505 Grommet
2913701 Bolt 1/4-20 X 1/2" Stainless
2914071 Locknut 1/4-20 Stainless
Item Part Description
No. No.
34 11377751 37° Flare Elbow 3/4" Brass
35a 11647846 Fill Tube Sub Assembly (Driver)
35b 11649227 Fill Tube Sub Assembly (Passenger)
36a 11377823 37° Flare Elbow 1/2" Brass
36b 11658596 37° Flare Elbow 1/2" Stainless - Dual Tank
37 11377778 37° Flare Elbow 3/8" Brass
38 11647871 Vent Tube Sub Assembly
39 10928902 BNC Patch Cord 3'
10746359 BNC Patch Cord 8'
11015144 BNC Patch Cord 10'
21
PARTS LISTVIII
25
34
35a
25
33c
39
34
35b
35b
35a
35a
35b
36b
33c
34
25
36a
33b
36a
35a
35b
33a
36b
25
34
36a
33b
36a
36a
36a
25
Shrouded Tank Configurations
Driver Single Passenger Single
Driver Dual Passenger Dual
Driver Dual
Remote Fill/ No Sender
Passenger Dual
Remote Fill
22
APPENDIX – Connections IX
4
3
1
7
8
30
30
30
10
Liquid Connection - 3/8" FPT
Relief Valve Connection - 3/8" FPT
Vent Connection - 3/8" FPT
Vent Valve - 3/8" FPT
Relief Valve Connection - 3/8" FPT
Liquid Connection - 3/8" FPT
Fill Connection - 3/8" FPT
(below 50 gallons)
Fill Connection - 1/2" FPT
(above 50 gallons)
Fuel Filling Connector
3 Pin Female Connector Housing
Weatherpak 12015793
Contents Gage
1/4" x .032 Spade
Connector
23
APPENDIX – ConnectionsIX
Heat Exchanger
Automatic Fuel Shut Off Valve
Specifications:
Max. Operating Pressure (LNG): 300 p.s.i.g.Max. Coolant Pressure: 50 p.s.i.g.
Part No. Horsepower A B C D ERating
10682851 150 11-1/4 4-1/2 5-1/2 7-1/2 4-5/89722999 300 19-1/4 4-1/2 14-3/4 15-3/4 4-5/810668725 450 27-1/4 5 21-1/2 22-1/2 5-1/2
Overpressure
RegulatorVent Check Valve
Vent Connectors
3/4-16 x 45° Flare 3/8" MPT
B
A
C (Max)
DCoolant In(1/2'' FPT)
Gas Out(3/8'' FPT)
Coolant Out(1/2'' FPT)
LNG In(3/8'' FPT)
LightGround
+12 VDC
GageSignal (Green)
GroundIgnition(+12 VDC)
Vehicle Half Sender Half
3 Pin Female Connector HousingWeather Pack 12010717
3 Pin Male Connector HousingWeather Pack 12015793
3/8" FPT
1/2" FPT
3/8" FPT
3/8" MPT
1/4" FPT
2 Pin Female
Connector Housing
Weatherpak 12015792
11 8
15
14
13
9
24
APPENDIX – Labels IX
METHANEREFRIGERATEDLIQUID
UN 1972
METHANEREFRIGERATED LIQUID
DANGER: CRYOGENIC LIQUIDAND GAS UNDER PRESSURE. CAN
FORM FLAMMABLE MIXTURES WITH AIR.MAY CAUSE RAPID SUFFOCATION. MAY CAUSEANESTHETIC EFFECTS. MAY CAUSE FROSTBITE.WARNING: SECURE ALL CYLINDERS WHILE IN
STORAGE AND IN USE.
ALWAYS KEEP CONTAINER IN UPRIGHT POSITION.THIS SIDE UP
Keep away from heat, flame and sparks. Store and use with adequate ventilation. Cylinder temperature should not exceed 250 F (121 C). Avoid breathing gas. Do not get liquid in eyes,
on skin or clothing. Close valves to isolate tank for maintenance operations. Use in accordance with operation manual.
FIRST AID: IF INHALED, remove to fresh air. If not breath- ing, give artificial respiration. If breathing is difficult, give oxygen. Call a physician.IN CASE OF FROSTBITE, obtain immediate medical attention. DO NOT REMOVE THIS PRODUCT LABEL.
FLAMMABLE GAS
2
P/N3835959 P/N 3830599 P/N 3830619 P/N 3830709
UN 1972 – P/N 3835959: This label identifies the LNG by itsHAZMAT identification number. Although not required,many safety, and emergency response organizations usethis number to identify hazards and formulate suitableresponses to accident situations.
LNG (Diamond) – P/N 10586412: Place these labels on theright rear and left front of the vehicle. It identifies the vehi-cle as an alternative fueled vehicle, that runs on LNG.
LNG 230 PSI Max – P/N 10647617: This label must be mounted in
plain sight near the fill connector. It is the most important label froma safety standpoint since it notifies the fuel station operator ofthe pressure limit of the vehicle tank.
Data Plate: Permanently affixed to the tank this label gives themodel number, serial number, date of manufacture, volumetriccapacity and working pressure information about the tank. Italso identifies the manufacturer and plant where built.
25
APPENDIX – Tank SpecificationsIX
0 100 1000200 300 400 500 600 700 800 900 1100 1200
20
40
60
80
100
120
140
0
Weight (pounds)
Ca
pa
cit
y (
ga
llo
ns)
Empty Weight
Full Weight
Gro
ss V
olu
me (
Gallo
ns)
16" Dia
20" Dia
22" Dia
24" Dia
26" Dia
Overall Length (Inches)
160
140
120
100
80
60
40
20
020 30 40 50 60 70 80 90
LNG Tank Length — Volume
LNG Tank Weights
A Chart Industries Company
P/N 3835849 Rev C.1 7/02
