A Guide to Commercial Hot Water from Hamworthy Guide to Commercial Hot Water from Hamworthy Introducing Hamworthy’s Product Ranges for Hot Water Generation: Dorchester Direct-Fired

A Guide to Commercial Hot Water from HamworthyIntroducing Hamworthy’s Product Ranges for Hot Water Generation: ■■ Dorchester Direct-Fired Water Heaters■■ Powerstock Indirect-Fired Calorifiers and Tanks■■ Solar Hot Water Systems

With guidance on hot water issues for a successful system implementation

2

OverviewHamworthy offer a comprehensive range of Natural gas, LPG, Oil, and solar powered solutions for the safe production of domestic hot water in commercial applications. These include Dorchester direct-fired water heaters, Powerstock calorifiers, and Dorchester DR-TC and Trigon solar hot water solutions.

This guide presents an overview of Hamworthy products for DHW (Domestic Hot Water) generation, covering single units with maximum power ranging from 18kW to 144kW, and maximum continuous output ranging from 370 litres/hour to 3250 litres/hour.

The guide also highlights some important issues associated with the production of potable domestic hot water that should be considered when specifying a commercial hot water system.

For more detailed technical information, refer to the sales brochure specific to each range which is available to download from: www.hamworthy-heating.com or on request from your area sales representative. Contact Hamworthy sales Tel: 0845 450 2865 Email: [email protected]

Talk to HamworthyWith such a wide choice of products available from Hamworthy, and with more than one potential solution to your DHW application, we always recommend that you discuss your requirements with our sales engineers.

With their extensive experience of commercial DHW systems and in-depth knowledge of Hamworthy products, they will be able to help you focus in on solutions that best fit your requirements; ultimately guiding you to the most appropriate solution, whatever your selection criteria and application needs.

Let Hamworthy help you make the right choice.

A Guide to Hot Water from Hamworthy

Dorchester DR-FC Evo Dorchester DR-LA/LP Dorchester DR-TC Solar Dorchester DR-RS

Contents

Overview . . . . . . . . . . . . . . 2

Talk to Hamworthy . . . . . . . . . . 2

Direct and Indirect Solutions . . . . . 3

Dorchester Water Heaters . . . . . 4

Introduction. . . . . . . . . . . . . . 4

Dorchester Specification . . . . . . . 5

Dorchester DR-FC Evo. . . . . . . . . 6

Dorchester DR-TC . . . . . . . . . . 7

Dorchester DR-LA/LP . . . . . . . . . 8

Dorchester DR-RS . . . . . . . . . . . 9

Dorchester DR-PF . . . . . . . . . . . 10

Dorchester DR-SA/SE . . . . . . . . . 11

Dorchester Options . . . . . . . . . . 12

Range & Model Comparisons . . . . . 14

Powerstock Calorifiers & Tanks . . 15

Introduction. . . . . . . . . . . . . . 15

Powerstock Calorifiers . . . . . . . . 16

Powerstock Storage Tanks . . . . . . 17

Powerstock Options. . . . . . . . . . 17

Trigon Solar & Dorchester DR-TC. . 18

Solar Hot Water Solutions. . . . . . . 18

Solar Systems Block Diagram . . . . . 19

Hot Water Information . . . . . . . 20

General Information . . . . . . . . . 20

Regulatory Information . . . . . . . . 22

Sizing and Hamworthy Services . . . . 23

Fully Automatic Condensing, Direct-Fired Water Heaters

The most versatile water heater from Hamworthy offering superior controls, excellent seasonal efficiencies up to 107% net and a wide range of room sealed and open flue options.

■■ 7 models■■ Continuous outputs 600–2400 litres/hour

■■ Reduced energy costs■■ Low noise■■ Can be installed close to the point of use

Fully Automatic Solar Water Heaters with Integral Direct-Fired Condensing Gas Burner

The innovative Dorchester DR-TC combines the use of solar energy with condensing gas fired capability using an intelligent control system.

■■ 2 heater models■■ 2 solar transfer stations ■■ Continuous outputs 820–1200 litres/hour

■■ Saves space■■ Prioritises solar energy over gas

Fully Automatic Multi-Tube Direct-Fired Water Heaters

A natural replacement for existing water heaters, the Dorchester DR-LA is compatible with most existing flue designs and comes with a choice of flue connection positions.


■■ Permanent pilot option (DR-LP)

■■ Simplifies installation in replacement projects

■■ 45° or optional horizontal flue connection

Room Sealed, Fully Automatic Direct-Fired Water Heaters

Dedicated room sealed water heater range with multi-tube heat exchanger.

■■ 5 models■■ Continuous outputs 507–1960 litres/hour Ideal for plant rooms with restricted ventilation or locations without a plant room

http://www.hamworthy-heating.com

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Powerstock Indirect-Fired Solutions

Preference may be to have a DHW system powered via the boiler heating system and/or via solar circuit, and not to have an additional gas-fired appliance at all. In this case, Hamworthy can offer a range of 7 Powerstock calorifiers for an indirect-fired hot water storage solution. Powerstock calorifiers are the obvious choice if the direct-fired solution is not a feasible option e.g. flue cannot be installed in the proposed building.

Powerstock calorifiers are available with single or twin coil heat exchangers. Twin-coil calorifiers allow the use of two independent heating sources, such as two gas boilers, or a gas boiler together with a biomass boiler or solar circuit. This adds both versatility and options for security of fuel supply, as well as the potential to introduce a proportion of heating via renewable means with the associated environmental and financial benefits. In addition all Powerstock calorifiers can also be directly electrically heated if fitted with an optional immersion heater.

Extending Storage Capacity with Powerstock Tanks

Hot water storage volumes for both direct-fired and indirect-fired solutions can be augmented efficiently by the use of one or more highly insulated Powerstock storage tanks.

There are 4 Powerstock storage tank models available ranging in capacity from 300 litres to 990 litres.

Trigon and Dorchester DR-TC Renewable Solutions

Hamworthy also offer the Trigon solar thermal hot water system product range in addition to the Dorchester DR-TC solar water heater for fully integrated renewable solutions to hot water generation.

Direct-Fired and Indirect-Fired

Dorchester water heaters are direct-fired units, meaning each has an integral gas or oil burner that directly heats the water in its storage cylinder by supplying hot gases through one or more heat exchanger fire tubes within the cylinder which then transfers heat to the surrounding water.

Conversely, Powerstock calorifiers, which have no integral burner, are indirect-fired units. Essentially they are storage water cylinders with single or twin heat exchanger coils. Each heat exchanger coil is then connected in a closed circuit with an external heating source such as a boiler, or solar collectors in solar circuit. The fluid is heated by the external source and pumped through the calorifier heat exchanger where it gives up heat to the stored water. As the stored water in calorifiers is indirectly heated by the external energy source (via the liquid heated directly by that source) calorifiers are referred to indirect-fired units.

Dorchester Direct-Fired Solutions

There are significant efficiencies to be gained by using a correctly sized, self-contained, direct-fired DHW system which is independent of the main building heating system, particularly if the application allows the heating boilers to be switched off during the summer months.

Similarly, energy can be saved by installing a direct–fired water heater close to the point of use, reducing the energy that is wasted over a long pipe run from a distant heat source.

Hamworthy offer an impressive 37 Dorchester direct-fired water heaters across 8 different ranges and 3 fuel types to cover the varied needs and priorities of specifiers and contractors, whatever their project’s DHW demand profile and product selection criteria.

Direct and Indirect Solutions

Dorchester DR-SA/SE Trigon Solar Dorchester DR-PF PowerstockPower Flame, Gas or Oil, Direct-Fired Water Heaters

Featuring a power flame burner the Dorchester DR-PF offers the highest outputs and is the only water heater that can use oil, natural gas or LPG.


■■ Greater flexibility with smaller flue diameter requirements

■■ Choice of fuel supply

Fully Automatic Single-Tube Direct-Fired Water Heaters

The lowest output water heaters in the Dorchester range, these are ideal for smaller applications.


■■ Permanent pilot option (DR-SE)

■■ Ultra quiet operation■■ DR-SE can operate without an electrical supply

Indirect-Fired Heating and Hot Water Storage

Offering a flexible approach to indirect heating and storage. Powerstock calorifiers and storage tanks can be easily coupled to any heating boiler or renewable energy source to provide highly efficient hot water generation.

Calorifiers


■■ Capacities 160–958 litres

Storage Tanks

■■ 4 models ■■ Capacities 300–990 litres

Solar Thermal Hot Water System

A complete package, which delivers everything required for an integrated solar hot water solution.

■■ Vertical or horizontal collectors

■■ On-roof or A-frame installation

■■ Standard or advanced controls

■■ Integrates with Dorchester water heaters or Powerstock calorifiers

A Guide to Hot Water from Hamworthy

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Dorchester Water HeatersIntroduction

Dorchester products range from 18.9kW to 144.1kW and offer continuous outputs from 370 litres/hour to 3250 litres/hour respectively, with operating efficiencies up to 107% net. Dorchester direct-fired water heaters are designed to operate typically at up to 80°C and at pressures up to 8 bar.

The Dorchester range extends from traditional atmospheric direct-fired water heaters with relatively simple on/off thermostat controls right through to advanced timer-controlled high-efficiency (107% gross) condensing water heaters such as the Dorchester DR-FC Evo and the Dorchester DR-TC. The Dorchester DR-TC is a combined solar and gas-fired solution which can take advantage of nominally “free” solar energy in place of gas heating whenever the temperature at its solar collectors is just a few degrees above that of its stored water. It comes with integrated solar controls and a solar transfer station with solar pump.

All Dorchester models require an appropriate flue and so the flue specification can be a key factor in deciding which Dorchester range is the most suitable for a particular application. If no flueing solution is feasible, then alternative solutions such as indirect-fired Powerstock calorifiers must be considered.

Hot water strategies and application constraints can result in the need for a modular approach where there may be more than one Dorchester water heater, and a complete system may include Powerstock calorifiers, additional storage tanks and solar thermal or other heating systems. Having more than one heating source allows for easier maintenance without loss of service. Alternatively, the load profile might be such that additional or alternative heating sources are only brought into service at certain times to satisfy peak load requirements.

There are many benefits to be gained by the incorporation of renewable energy systems into commercial hot water systems. The Dorchester DR-TC water heater addresses this directly with its integrated solar function. Similarly, Dorchester direct-fired water heaters can be supplied with a solar pre-heated cold water feed, using a Hamworthy Trigon solar system. Renewable solutions attract a range of financial incentives to encourage their take-up, as well as offering immediate savings in fossil fuel usage.

A modular approach is used in the example below, in which the DHW system combines a indirect-fired solution with a direct-fired solution, with additional buffering at both stages.

A combined Powerstock calorifier and Powerstock tank is heated by an external heat source (typically by a solar circuit, but in this case by an air–sourced heat pump), and act together as a thermal store to provide a preheated cold water feed to the Dorchester DR-FC Evo direct-fired condensing water heaters. These water heaters are sequenced to operate alternately. Each water heater is fitted with an optional top-to-bottom recirculation kit, and also an optional unvented kit (with re-sized expansion vessel and a safety pressure-and-temperature relief valve). The water heaters are also coupled to another storage tank (not shown) to increase the overall DHW volume to meet the demand requirements of the application.

A commercial Domestic Hot Water (DHW) plant featuring a Powerstock calorifier (left) with adjacent Powerstock storage tank providing pre-heated water for input to two Dorchester DR-FC Evo 25 water heaters—each fitted with top-to-bottom recirculation kit and unvented kit options.

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ConstructionAll Dorchester ranges are built to last using high quality steel tanks and heat exchangers. For the safe production of potable hot water, a high quality vitreous enamel glaze is baked on to all tank interior and heat exchanger surfaces, creating a hygienic surface finish which gives excellent protection against corrosion. Additional corrosion protection is provided by either electrical anode protection or sacrificial magnesium anode systems, depending on the range type, and options selected. Access doors are provided for inspection and cleaning of internal surfaces, and all units are supplied fully insulated with CFC-free foam to minimise standing losses.

Burners

The Dorchester atmospheric water heater ranges: DR-LA/LP, DR- SA/SE, DR-RS, and Dorchester power flame DR-PF range, have burners at the base of the hot water cylinder and are up-firing. The Dorchester condensing water heater ranges: DR-FC Evo and DR-TC, have fan-blown down-firing pre-mix burners mounted at the top of the hot water cylinder.

Heat Exchangers

In the down-firing condensing water heater ranges (Dorchester DR-FC Evo and DR-TC), the single heat exchanger has a lengthy fire tube which first descends then rises and then descends again as a spiral coil before exiting the tank via a rising flue at the side of the tank. As the flue gases pass through the fire tube, they give up heat to the surrounding water, and consequently cool down as they pass through the tube to the flue.

This type of heat exchanger is designed to maximise heat transfer but also to encourage the flue gases to cool sufficiently to cause some gases to condense, and so change state from a gas to a liquid. This change of state releases energy (latent heat) in the process which further heats the stored water, maximising the energy transferred and raising the overall efficiency of the water heater. Any condensate formed in this process is released via a condensate trap.

This design of heat exchanger inhibits problems with scale as any build up will fall away to the base of the unit and not affect heat transfer or create hot spots.

In the Dorchester DR-RS, DR-LA/LP and DR-PF up-firing burner ranges, multiple vertical fire tubes are arranged through the centre of the cylinder in the. Each fire tube is fitted with a flue baffle to maximise heat transfer and increase operational efficiency.

The up-firing Dorchester DR-SA/SE ranges use a baffled single vertical fire tube flue.

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Designed for Safety

Dorchester water heaters conform to HSC Approved Code of Practice and Guidance Document L8 for minimising the risk of Legionella, with design features such as:

■■ Good access for cleaning■■ Generous flow and return connections■■ Adequately sized drain■■ Base designed to avoid sludge traps■■ Anodes to inhibit metal corrosion■■ Number of tappings correctly positioned to facilitate recirculation, destratification and to obviate stagnation areas

■■ Designed to meet unvented supply requirements

In the DR-FC Evo and DR-TC models, specific anti-Legionella cycles can be programmed to run automatically. For more information on Legionella and its prevention, please refer to page 20. Gas safety is integral to the design of Dorchester water heaters, and as such all burners are protected with automatic flame detection systems which will shut off the gas supply in the case of a burner flame being extinguished.

Other safety systems include over-temperature protection (with lockout and manual reset) and over pressure protection on unvented systems. Frost protection is set to operate the water heater if the stored water temperature falls below 5°C is also available on all models except DR-SA/SE and DR-LP.

The DR-FC Evo and DR-TC ranges have advanced electronic control and monitoring capabilities, with diagnostics for effective maintenance, as well as an alert when a service is due based on hours run.

In addition to the temperature sensors and electronic controls supplied with the Dorchester DR-TC solar water heater for the safe monitoring and control of its solar circuit, there is additional solar safety equipment in the dedicated solar transfer station supplied with the water heater, including safety valves, temperature and pressure gauges and connections for a solar expansion vessel.

Dorchester Water HeatersSpecification

Cover

Hot water outlet

Electrical connector block

Controller

Pressure switch

Control panel

Top store temperature sensor

Combustion chamber

Anode

Tank

Heat exchanger

Clean out door

Mid store temperature sensor

Cold water inlet

Drain valve

Burner assembly

Air supply hose

Condensate trap

Concentric flue pipe

Insulation layer

Base

Solar heat exchanger

Solar coil inlet

Flue gas test point

Solar coil temperature sensor

Solar coil outlet

Plate heat exchangersupply (not used)

Plate heat exchangerreturn (not used)

Recirculation connection

Cutaway of a Dorchester DR-TC showing a down-firing pre-mix burner and condensing heat exchanger, with solar coil below.

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Dorchester DR-FC Evo Fully Automatic, CondensingDirect-Fired Water Heater

Features

■■ Modulating premix burner ■■ Condensing heat exchanger ■■ Natural Gas or LPG■■ Hamworthy flue terminals■■ Room sealed or open flue options

■■ Flue schemes: B23, C13, C33 and C53

■■ For open vented or unvented* water supplies

■■ Electronic controls: ON/OFF or programmable multi-period 7 day timer with programmable extra period, hysteresis, external pump timer, anti-Legionella cycle and frost protection. Remote enable. Control, limit and safety thermostats. Remote data monitor option.

■■ Corrosion protection: electrical anode

■■ Clean out door

98%

SpecificationDorchester DR-FC Evo Model

DR-FC Evo 25

DR-FC Evo 30

DR-FC Evo 45

DR-FC Evo 60

DR-FC Evo 80

DR-FC Evo 95

DR-FC Evo 120

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Continuous output with 44°C ∆T l/h 600 630 970 1200 1700 2000 2400


Storage capacity l 227 386 504

Maximum operating water pressure, open vented water supply bar 8 bar

Maximum operating water pressure, unvented water supply bar 3.5 bar (=cold feed pressure reducing valve preset in unvented kit option)

Maximum water temperature °C 80

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Input power, gross–maximum kW 31.6 32.6 51.2 62.1 85.0 103.4 126.3

Output power–maximum kW 30.5 32.0 49.3 59.3 82.6 98.7 119.4

Heating up time, ∆T = 44°C min 23 37 24 20 19 16 13


Standby losses kW/24h 4.2 4.7 4.7 4.7 6.7 6.7 6.7

Gas

NG

Gas G20 inlet pressure–nominal mbar 20

Gas G20 flow rate–maximum @1013.25 mbar and 15°C m3/h 3.1 3.2 5.0 6.0 8.3 10.1 12.3

LPG

LPG G31 inlet pressure–nominal mbar 37

LPG G31 flow rate–maximum @1013.25 mbar and 15°C kg/h 2.3 2.3 3.7 4.4 6.1 7.4 9.0

Dim

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Width (W) mm 925 1000

Depth (D) mm 850 900

Height (H) mm 1485 2005 2060

Flue spigot diameter mm 100/150 130/200

Gas inlet connection–type/diameter inch Rp ¾"

Hot water outlet–type/diameter inch R 1½"

Cold water inlet–type/diameter inch R 1½"

Weight when empty kg 202 239 480

Power consumption-maximum W 45 45 75 115 95 145 240

Electrical supply VAC 230 V 1Ph 50Hz

Notes: All data is based on Natural Gas G20 usage unless otherwise stated.

*For unvented water supplies use optional unvented kit.

For C13 and C33 flues, dedicated Dorchester flue terminals (supplied separately, and CE-approved for use with the appliance), must be used. B23 and C53 terminal and other flue components are also available.

Allow clearances of 1000mm above the water heater, 1000mm around the controls and clean-out doors, and 500mm around all other sides.

For full technical details, including flues, refer to the Dorchester DR-FC Evo technical brochure 500002614 and installation manual 500001195.

The most versatile water heater from Hamworthy offering superior controls, excellent seasonal efficiencies up to 107% net and a wide range of room sealed and open flue options.


■■ Reduced energy costs■■ Low noise■■ Can be installed close to the point of use

Ultra-Quiet<45dBa

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Dorchester DR-TCFully Automatic Solar Water Heaters with IntegralDirect-Fired Condensing Gas Burner

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SpecificationDorchester DR-TC Model

DR-TC 40 DR-TC 60

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Continuous output with 44°C ∆T l/h 820 1200


Storage capacity l 388

Maximum operating water pressure, open vented water supply bar 8



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Input power, gross–maximum kW 43.5 62.1

Output power–maximum kW 41.9 59.3

Heating up time, ∆T = 44°C min 16 11


Standby losses kW/24h 5.3

Gas

NG


Gas G20 flow rate–maximum @1013.25 mbar and 15°C m3/h 4.2 6.0

LPG


LPG G31 flow rate–maximum @1013.25 mbar and 15°C kg/h 3.1 4.4

So

lar Maximum pressure, solar circuit kPa/(bar) 600 (6)

Transfer Station TX1 flow rate l/min 0.5 to 15 (for 2 to 15 Trigon collectors)

Transfer Station TX2 flow rate l/min 4 to 22 (for 6 to 20 Trigon collectors)

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Width (W) mm 850

Depth (D) mm 925

Height (H) mm 2055

Flue spigot diameter mm 100/150


Hot/cold water connections–type/diameter inch R 1½"

Solar coil supply/return–type/diameter inch Rp 1"

Weight when empty kg 245

Power consumption-maximum W 60 + solar control (max 700) 120 + solar control (max 700)


Notes: All data is based on Natural Gas G20 usage, and excludes solar, unless otherwise stated. *For unvented water supplies use optional unvented kit. For C13 and C33 flues, dedicated Dorchester flue terminals (supplied separately, and CE-approved for use with the appliance), must be used. B23 and C53 terminal and other flue components are also available.Allow clearances of 1000mm above the water heater, 1000mm around the controls and clean-out doors, and 500mm around all other sides. For full technical details, including flues, refer to the Dorchester DR-TC technical brochure 500002598 and installation manual 500001196.

Features■■ Modulating premix burner■■ Solar Transfer station with modulating solar pump

■■ Condensing heat exchanger + solar heat exchanger

■■ Solar operation with Natural Gas or LPG back-up

■■ Hamworthy flue terminals■■ Room sealed or open flue options

■■ Flue schemes: B23, C13, C33 and C53


■■ Electronic controls: as per DR-FC Evo, plus an integrated solar circuit control system with solar priority, and optional dummy sensor for gas-only "solar ready" operation prior to fitting any solar collectors

■■ Corrosion protection: electrical anode

■■ Clean out door■■ Compatible with Hamworthy Trigon collectors

Combines the use of solar energy with a condensing gas fired water heater using an intelligent control system.

■■ 2 models■■ 2 Transfer stations ■■ Continuous outputs 820–1200 litres/hour

■■ Saves space■■ Prioritises solar energy over gas

Up to 30kW of solar heating

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Features

■■ Atmospheric burner ■■ Ignition: Fully automatic with flame detection (DR-LA) or permanent pilot with thermocouple (DR-LP)

■■ Natural Gas or LPG■■ Draught diverter with 45° or horizontal flue connection

■■ For B23 flue schemes or fan dilution systems*

■■ For open vented or unvented** water supplies

■■ Controls: ON/OFF, thermostat (control, limit and safety), power indicator, lockout and reset, volt free-contacts. Frost protection (on DR-LA only)

■■ Combustion products safety discharge device

■■ Corrosion protection: Magnesium sacrificial anode or optional electrical anode


SpecificationDorchester DR-LA/LP Model

DR-LA/LP 30

DR-LA/LP 40

DR-LA/LP 45

DR-LA/LP 60

DR-LA/LP 75

DR-LA/LP 95

DR-LA 110

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Storage capacity l 324 374 312 351 291 265 264




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Input power, gross–maximum kW 41.4 55.4 65.2 81.0 96.4 124.2 140.6

Output power–maximum kW 31.7 41.9 49.3 61.2 72.9 93.9 107.6




Gas

NG


Gas G20 flow rate–maximum @1013.25 mbar and 15°C m3/h 4.0 5.4 6.3 7.9 9.4 12.1 13.7

LPG


LPG G31 flow rate–maximum @1013.25 mbar and 15°C kg/h 2.7 3.7 4.5 5.6 6.4 8.1 9.3

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Width (W) including 45° draft diverter mm 1100 1105

Depth (D)–diameter excluding control column(including control column) mm

710(800)

Height (H) including 45° draft diverter,(including horizontal diverter) mm

1900(1975)

2100(2175)

1900(1975)

2040(2115)

2000(2060)

2025(2070)

2085(2130)

Flue spigot diameter with 45° draft diverter,(with horizontal draft diverter option) mm

150 (150)

180 (150)

180 (180)

225 (180)

225 (225)

225(225)

Gas inlet connection–type/diameter inch Rp ¾" Rp 1"

Hot water outlet–type/diameter inch Rp 1 ½"

Cold water inlet–type/diameter inch R 1 ½"

Weight when empty kg 195 221 209 238 244 270 329

Power consumption W 30 60


Notes: All data is based on Natural Gas G20 usage, unless otherwise stated.

*Flue design and terminals are not HH supply. **For unvented water supplies use optional unvented kit.


For full technical details, refer to the Dorchester DR-LA/LP technical brochure 500002519 and installation manuals 500001136 (DR-LP) and 500001137 (DR-LA) .

A natural replacement for existing water heaters, the Dorchester DR-LA (or permanent pilot option DR-LP) is compatible with most existing flue designs.


■■ Simplifies installation in replacement projects

■■ 45° flue connection (or horizontal option)

ExceedsMinimum

Requirementsfor ExistingBuildings

Easy fit replacement water heater for open

flued applications

Dorchester DR-LA/DR-LPFully Automatic Multiple-TubeDirect-Fired Water Heaters

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Dorchester DR-RSRoom Sealed, Fully Automatic Direct-Fired Water Heaters

Features

■■ Atmospheric burner ■■ Fully automatic ignition with flame detection

■■ Natural Gas or LPG■■ Hamworthy flue terminals■■ For room sealed flue schemes: C13, C33 and C53*

■■ For open vented or unvented** water supplies

■■ Controls: ON/OFF, thermostat (control, limit and safety), power indicator, lockout and reset, volt free-contacts



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SpecificationDorchester DR-RS Model

DR-RS 25 DR-RS 40 DR-RS 65 DR-RS 85 DR-RS 105

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Continuous output with 44°C ∆T l/h 507 811 1293 1740 1960

Continuous output with 50°C ∆T l/h 446 714 1138 1531 1725

Storage capacity l 324 312 265 265 265




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Input power, gross–maximum kW 31.6 51.2 81.6 111.1 125.2

Output power–maximum kW 25.9 41.5 66.2 89.0 100.3

Heating up time, ∆T = 44°C min 38 23 12 9 8

Heating up time, ∆T = 50°C min 43 26 14 10 9

Standby losses kW/24h 9.0 10.4 8.3 9.0 9.9

Gas

NG


Gas G20 flow rate–maximum @1013.25 mbar and 15°C m3/h 3.1 5.0 7.9 10.8 12.2

LPG

LPG G31 inlet pressure–nominal mbar 37 No LPG variant, Natural gas

onlyLPG G31 flow rate–maximum @1013.25 mbar and 15°C kg/h 2.2 3.4 5.5 7.9

Dim

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Width (W) mm 755

Depth (D) mm 1000

Height (H) mm 1995 2020

Flue spigot diameter mm 80/125 100/150 130/200 2 x 130 (twin duct)

Gas inlet connection–type/diameter inch Rp ¾" Rp 1”

Hot water outlet–type/diameter inch Rp 1½"

Cold water inlet–type/diameter inch Rp 1½"

Weight when empty kg 230 245 295 320 320

Power consumption W 100 275 300



*Flue design and terminals are not HH supply.**For unvented water supplies use optional unvented kit.

For C13 and C33 flues, dedicated Dorchester flue terminals (supplied separately, and CE-approved for use with the appliance), must be used; other flue components are also available.


For full technical details, refer to the Dorchester DR-RS technical brochure 500002629 and installation manual 500001138.

Dedicated room sealed water heater range with multi-tube heat exchanger.


■■ Ideal for plant rooms with restricted ventilation or locations without a plant room

ExceedsMinimum


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Dorchester DR-PF

Power flame, Gas or Oil, Direct-FiredFully Automatic Water Heaters

Features

■■ Power flame Riello burner ■■ Fully automatic ignition with flame detection

■■ Natural Gas, LPG or Oil■■ For B23 open flue schemes*■■ For open vented or unvented** water supplies

■■ Controls: ON/OFF, thermostat (control, limit and safety), power indicator, lockout and

reset. Air and gas proving switches




ExceedsMinimum


SpecificationDorchester DR-PF Model

DR-PF 55 DR-PF 65 DR-PF 75 DR-PF 95 DR-PF 115 DR-PF 145

Wate

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Continuous output with 44°C ∆T l/h 965 1207 1448 1850 2172 2816

Continuous output with 50°C ∆T l/h 850 1062 1274 1628 1911 2478

Storage capacity l 338 333 296 271




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Input power, gross–maximum kW 65.3 81.6 97.9 125.2 146.9 190.5

Output power–maximum kW 49.4 67.7 74.1 94.7 111.1 144.1

Heating up time, ∆T = 44°C min 21 17 14 10 8 6

Heating up time, ∆T = 50°C min 24 19 16 11 9 7

Standby losses kW/24h 8.7 8.7 8.7 8.7 8.7 8.7

Gas

an

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NG


Gas G20 flow rate–maximum @1013.25 mbar and 15°C m3/h 6.3 7.9 9.5 12.2 14.3 18.5

LPG


LPG G31 flow rate–maximum @1013.25 mbar and 15°C kg/h 4.7 5.8 7.0 8.9 10.5 13.6

Oil Oil flow rate–maximum, with

maximum viscosity@20°C=6mm2/s kg/h 5.3 6.3 7.4 9.5 11.6 16.9

Dim

en

sio

ns

Width (W) mm 705

Depth (D) (excluding burner) mm 725

Height (H) mm 1900 1990

Flue spigot dia. (without adaptors) mm 150*** 200 250***


Hot water outlet–type/diameter inch Rp 1½"

Cold water inlet–type/diameter inch Rp 1½"

Weight when empty kg 230 240 265 305

Power consumption W 180 385 390



*Flue design and terminals are not HH supply.**For unvented water supplies use optional unvented kit.***Diameter after fitting flue reducer.

Allow clearances of 1000mm above the water heater, 1000mm around the controls and clean-out doors, 600mm in front of burner and 500mm around all other sides.

For full technical details, refer to the Dorchester DR-PF technical brochure 500002631 and installation manual 500001139.

Featuring a power flame burner the Dorchester DR-PF offers the highest outputs and is the only water heater that can use oil, natural gas or LPG.


■■ Greater flexibility with smaller flue diameter requirements

■■ Choice of fuel supply

Rapid recovery:Only 6 mins for

DR-PF 145

WD

H

http://hamworthy-heating.com/Shared/Files/Dorchester-DR-PF-water-heater-brochure-500002631A.pdf

11

Dorchester DR-SA/DR-SE Fully Automatic Single-TubeDirect-Fired Water Heaters

Features

■■ Atmospheric burner ■■ Ignition: Fully automatic with flame detection (DR-SA) or permanent pilot with thermocouple (DR-SE)

■■ Natural Gas or LPG■■ For B23 open flue schemes or fan dilution systems*

■■ Draught diverter■■ For open vented or unvented** water supplies

■■ Controls: ON/OFF, thermostat (control and safety), lockout and reset. Power indicator (DR-SE only)




Do

rch

este

r W

ater

Hea

ters

ExceedsMinimum


The lowest output water heaters in the Dorchester range, these are ideal for smaller applications.


■■ Permanent pilot option (DR-SE)

■■ Ultra quiet operation■■ DR-SE can operate without an electrical supply

SpecificationDorchester DR-SA/SE Model

DR-SA/SE 16 DR-SA/SE 19

Wate

r



Storage capacity l 278 372



Maximum water temperature °C 80 80

En

erg

y

Input power, gross–maximum kW 24.7 26.2

Output power–maximum kW 18.9 20.1



Standby losses kW/24h 11.3 N/A

Gas

NG


Gas G20 flow rate–maximum @1013.25 mbar and 15°C m3/h 2.4 2.5

LPG


LPG G31 flow rate–maximum @1013.25 mbar and 15°C kg/h 1.6 1.8

Dim

en

sio

ns

Width (W) mm 645 678

Depth (D) mm 770 775

Height (H) mm 1585 1780

Flue spigot diameter mm 130

Gas inlet connection–type/diameter inch Rp ½"

Hot water outlet–type/diameter inch Male NPT 1" (11.5 t.p.i.) Male NPT 1 ¼" (11.5 t.p.i.)

Cold water inlet–type/diameter inch Male NPT 1" (11.5 t.p.i.) Male NPT 1 ¼" (11.5 t.p.i.)

Weight when empty–DR-SA (DR-SE) kg 117 (122) 144 (149)

Power consumption–DR-SA (DR-SE) W 30 (0) 30 (0)

Electrical supply VAC 230 V 1Ph 50Hz 230 V 1Ph 50Hz***


*Flue design and terminals are not HH supply. **For unvented water supplies use optional unvented kit. *** Basic DR-SE requires no power supply—230V mains supply only required if any electrical options are to be used.


For full technical details, refer to the Dorchester DR-SA/SE technical brochure 500002630 and installation manuals 500001135 (DR-SA) and 500001134 (DR-SE).

DR-SENeeds no power

supply

WD

H

http://hamworthy-heating.com/Shared/Files/Dorchester-DR-SA_SE-water-heater-brochure-500002630A.pdf

12

Dorchester Options*Equivalent Powerstock Options also Available

Fuel Options

All models can be supplied to operate with Natural Gas (G20) or LPG (G31); in addition the Dorchester DR-PF can also be supplied to operate with 35 sec oil. Changeover from one fuel type to another will require components to be changed, and any changeover must be carried out by suitably qualified and certified personnel.

Unvented Supply Kit*

For applications fed by unvented mains cold water supplies, Hamworthy offer an unvented supply kit which is a purpose designed and sized kit of components, supplied loose, and comprises:

■■ Strainer■■ Pressure reducing valve 3.5 bar■■ Non return valve■■ Expansion relief valve, 6 bar■■ Expansion vessel connection■■ Expansion vessel, sized for 3.5 bar charge pressure

■■ Temperature and Pressure relief valve 7 bar at 95°C

■■ Tundish

Corrosion Protection Options*

All Dorchester and Powerstock models are "glass-lined". This means that a vitreous enamel coating has been applied to all internal water-side surfaces of the steel tanks, fire tubes and/or coils to ensure hygienic potable water storage and to protect from corrosion.

To provide additional corrosion protection, one of two electrochemical systems are also used in all Dorchester and Powerstock models. Both systems are inherently safe and do not affect the taste of the water.These are:■■ Electrical anode protection, or ICCP (Impressed Current Cathodic Protection)—supplied as standard in DR-TC, DR-FC Evo,

■■ Magnesium sacrificial anode protection (Cathodic Protection) —supplied in all other models as standard, but all models have the option to be supplied instead with an electrical anode protection system.

Electrical Anode Protection*

Electrical anode protection, or ICCP (Impressed Current Cathodic Protection) works by applying a

controlled DC protection current, via an electrical anode inserted in the tank, to maintain the tank metal within a passive electrode potential zone where corrosion is inhibited.

The anode (positive) in this system is a powered titanium electrode and the tank steel is the cathode (negative). The storage water acts as an electrolyte creating an electrical circuit between anode and cathode should any tank metal come into direct contact with water.

A potentiostat circuit continuously monitors the potential and automatically adjusts the anode current to maintain the tank metal at the correct potential to inhibit corrosion.

For effective protection the electric anode system must always be switched on. Therefore it is essential that an uninterrupted power supply is used to ensure power is always supplied to any water heater using this system.

Electrical anode protection offers excellent corrosion protection with water supplies having electrical conductivity as low as 125uS. In addition there is no “sacrificial” anode to replace periodically, so less maintenance is needed.

Magnesium Sacrificial Anode Protection*

Magnesium sacrificial anode protection, or Cathodic Protection, takes advantage of the fact that a less noble (relative position in the galvanic series) material such as magnesium will corrode in preference to a more noble material such as steel when electrically connected together and immersed in an electrolyte.

In practice, the steel cylinder and internals are electrically connected to a magnesium sacrificial anode rod fitted inside the cylinder. Should for any reason damage occur to the enamelling such that the steel is allowed to come into direct contact with the stored water (the electrolyte), then an electrochemical circuit is formed, with the steel becoming the negative cathode and the magnesium rod the positive anode. The magnesium anode will then be “sacrificed” and corrode in preference to the steel, thus protecting the cylinder and internals from corrosion.

This system has the advantage of requiring no external electrical supply,

and operates with water supplies having electrical conductivity as low as 250uS. However, as part of routine maintenance, the magnesium anode will need to be checked and eventually need replacing as it will gradually dissolve over time. To assist replacement, Hamworthy can offer flexible “sausage-link” easy-fit replacement magnesium anodes which are particularly useful if maintenance access is restricted.

Please note, electrical anode protection can, as an option, be fitted on all Dorchester water heaters that are normally fitted with magnesium sacrificial anode protection, in place of that protection. It is not possible to use both systems together in the same water heater because one system would work against the other and could potentially damage the cylinder. Also note magnesium sacrificial anodes cannot be fitted to the Dorchester DR-FC Evo or DR-TC.

Top-to-Bottom Recirculation Kit*

In order to prevent stratification within the heater, thus creating a zone of lower temperature water that can possibly lead to the proliferation of Legionella bacteria, an optional top to bottom re-circulation kit should be specified. By constantly returning water from the flow back into the base of the heater, a uniform temperature is maintained. The kit includes a pump, isolation valves, non-return valve and pipework for fitting on site.

Typical top-to-bottom recirculation kit

13

Dorchester OptionsIncluding DR-TC Solar Options

Time Clock Control (DR-SE only)

Where there is a requirement for the heater to be controlled by an external signal, such as a time clock or safety interlocks, then an optional control kit can be fitted. The kit comprises a solenoid valve that fits between the control valve and the burner. This kit will require a 230 volt, 50Hz single phase power supply.

Remote Monitor/BMS Interface (DR-FC Evo/DR-TC only)

A remote monitoring unit (BMS Interface) is available which acts as a bus-connection interface between the water heater controller and a Building Management System (BMS), allowing water heater data to be displayed at the BMS.

Solar Options (DR-TC only)

Solar Collector Field

To take advantage of nominally “free” solar energy in place of gas heating, the Dorchester DR-TC requires a solar collector field.

An appropriately sized collector field can be built quickly and easily from the Hamworthy Trigon solar products range, including vertical or horizontal collectors and associated roof or floor mounting equipment and ancillaries.

Hamworthy recommend its Trigon flat-plate solar collectors for use with the Dorchester DR-TC system. These rugged, highly efficient collectors are designed to BS EN12975. They feature a one-piece aluminium casing and tempered glass cover housing a specially coated absorber.

The Dorchester DR-TC solar system can be sized up to 40m2 collector area using a maximum of 20 Hamworthy Trigon vertical (2.3 V) or horizontal (2.3H) flat plate collectors, in a single field of collectors (i.e. powered by a single pump transfer station), and organised in any array combination.

It is recommended to use Tyfocor L as the solar fluid (40% propylene glycol) in the sealed solar circuit. This offers corrosion protection and also antifreeze protection to -18°C.

Dorchester Solar Transfer Stations

A solar station is supplied with each Dorchester DR-TC and connects the solar collector field to the water heater solar coil. Hamworthy offer a choice of two similarly equipped solar transfer stations, TX1 and TX2. Each features a modulating pump and safety equipment such as supply and return temperature gauges, visual flowmeter, non-return valve, isolation and 6 bar safety pressure relief valves, and a connection for a solar expansion vessel.

The TX1 is for use with systems with 0.5 to 15 l/min. solar circuit flow capacity, and for use with 4 to 30m2 of total collector area (e.g. for 2 to 15 Trigon collectors).

The TX2 is for use with systems with 4 to 22 l/min solar circuit flow capacity, and for use with 12 to 40m2 of total collector area (e.g. for 6 to 20 Trigon collectors).

Please note that TX1 and TX2 are dedicated transfer stations for use with only the Dorchester DR-TC and not with Trigon systems. Similarly Trigon solar transfer stations cannot be used with the DR-TC control system.

Dorchester TX1 solar transfer station

For more information on Trigon collectors and mounting equipment, transfer stations and ancillaries, please refer to the Trigon brochure 500002597.

Heat Meter/RHI Heat Meter

Heat metering is integrated into the Dorchester DR-TC controller (requires an optional Q/T sensor). An optional Renewable Heat Incentive (RHI)compliant heat meter, with an optional RS232 Interface for this meter is also available.

Remote Display

A wall-mounted display unit is available which shows in real time the solar contribution of the system.

Remote display

Dummy Sensor

A dummy sensor option allows the Dorchester DR-TC to be installed as a “Solar Ready” water heater, so that it can operate in a gas-burner only mode without an attached solar circuit. This is a useful option if it is intended to use the water heater ahead of completing the solar circuit.

Do

rch

este

r W

ater

Hea

ters

An array of two Trigon 2.3V solar collectors, A-frame mounted for flat roof or ground fixing

http://hamworthy-heating.com/Shared/Files/Trigon-Solar-Brochure_500002597A.pdf

14

Dorchester Water HeatersRange & Model ComparisonsKey to Tables

Dorchester DR-SA/SE Dorchester DR-TC Dorchester DR-PF Dorchester DR-LA/LP Dorchester DR-FC Evo Dorchester DR-RS

Table 1. Dorchester Water Heaters in Order of Increasing Maximum Output Power (kW)

Table 2. Dorchester Water Heaters in Order of Increasing Maximum Continuous Outputs (Litres/Hour)

Table 3. Dorchester Water Heaters in Order of Increasing Recovery Time (Minutes)

Table 4. Dorchester Water Heaters in Order of Increasing Maximum Storage Volume

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

18.9 20.1 25.9 30.5 31.7 32.041.5 41.9 41.9

49.3 49.3 49.459.3 59.3 61.2 61.7 66.2

72.9 74.182.6

89.0 93.9 94.7 98.7 100.3107.6 111.1

119.4

144.1

Max

. Out

put P

ower

/ k

W

Dorchester Models

Dorchester Water Heater Models by Increasing Output Power

0

500

1000

1500

2000

2500

3000

369 392507 600 620 630

811 819 820964 965 970

1197 1200 1200 1207 12931425 1448

1700 1740 1836 1850 1960 2000 2103 21722400

2816

Max

. Con

tinuo

us O

utpu

t / L

itre/

hour

Dorchester Models

Dorchester Water Heater Models by Increasing Continuous Output

0

10

20

30

40

50

60

6 7 8 8 8 9 10 11 12 12 13 14 16 16 17 17 19 19 20 21 23 23 2427

31

37 38

45

57

Max

. Rec

over

y Ti

me

/ M

inut

es

Dorchester Models

Dorchester Water Heater Models by Increasing Recovery Time

0

100

200

300

400

500

600

227264 265 265 265 265 271 278 291 296 296 312 312 324 324 333 338 338 351 372 374 386 386 386 388 388

504 504 504

Max

. Sto

rage

Vol

ume

/ Li

tre

Dorchester Models

Dorchester Water Heater Models by Increasing Storage Volume

15

Powerstock Calorifiers and TanksIntroduction

The efficient generation of hot water for use in commercial buildings can be achieved using direct or indirect-fired heating solutions.

The Hamworthy range of Powerstock calorifiers offers a flexible approach to indirect heating and storage of hot water, using a choice of energy sources. High efficiency gas fired boilers are commonly used with calorifiers as the primary energy source, but with the trend towards incorporating renewable energy into DHW systems, alternative technologies can also be used, such as solar thermal and biomass, as either the primary source, or as the primary or secondary energy source in a combined system using a twin coil calorifier.

There are 7 models in the Powerstock calorifier range with continuous outputs from 569 litres/hour to 1858 litres/hour based on a temperature rise ∆T across the calorifier of 44°C. Storage capacities are from 160 litres to 958 litres. All but the smallest models have twin coil heat exchangers which can be connected in series if using a single heat source, or connected separately when using two heat sources.

Powerstock storage tanks range from 300 litres to 990 litres capacity and can be used in a variety of applications either to maximise energy efficiency or increase system security.

Powerstock calorifiers and storage tanks are all approved by the Water Regulations Advisory Service (WRAS) to comply with the requirements of the UK Water Supply (Water Fittings) Regulations and Scottish Water Byelaws, when correctly installed.

The Hamworthy Powerstock range of calorifiers and storage tanks provide plenty of choice in meeting hot water demands for a wide variety of commercial applications.

Powerstock products are manufactured to the highest standards using the latest production technology to ensure a high quality long lasting finish in every unit. Compliance is assured with stringent controls in accordance with the European Standards for CE marking, and all models are Water Regulations Advisory Scheme (WRAS) approved.

Cylinders are constructed from high grade steel with a high quality vitreous enamel lining, and the five largest units in the Powerstock calorifier range incorporate a twin coil arrangement where two separate heat sources can be used. Alternatively the coils can be linked in series to maximise the output when connecting to single heat source.

Twin coil construction allows the designer to choose the configuration in which to connect the coils, to best suit the application, either in series or in parallel. This allows greater control of the heat input and gives the ability to utilise alternative energy sources such as a solar collector array.

All Powerstock models are supplied as standard with a pre-wired control panel having a temperature control thermostat and a limit thermostat; and each model is equipped with a magnesium sacrificial anode and clean out door as standard, insulated with CFC-free PU foam for low standing losses and finished in a smart insulated PVC factory-fitted jacket.

Options are available including an unvented supply kit, top-to-bottom pump recirculation kit, electrical anode protection and an electric immersion heater.

Seven models available in the Powerstock range of calorifiers Twin coils in Powerstock calorifiers enable two independent energy sources to be used to heat a common store.

Pow

erst

ock

Cal

orifi

ers

and

Tank

s

16

Powerstock CalorifiersIndirect-Fired Heating and Hot Water Storage

Notes: Calorifier performance is based on a DHW flow temperature of 60°C, with a cold water inlet temperature of 10°C (∆T=50°C across the water heater), and a coil inlet temperature of 80°C.

Input power, flow rate through coil, and coil pressure loss, are given at a coil outlet temp of 69°C (coil ∆T =11°C). Coil data on twin coil calorifiers is for top and bottom coils together in series.

*For unvented water supplies use optional unvented kit.

**May need to add up to 10% on to Input Power value to account for pipework losses if heat source is non-adjacent.

Allow clearances of 350mm above the water heater if unvented kit is fitted (On PS750 and PS1000 allow 1300mm for anode removal from top), 1000mm around the controls, 1000mm around the clean-out doors and in front of side-mounted anodes, and 500mm around all other sides.

For full details, including top only or bottom only coil performance, refer to the Powerstock technical brochure 500002488 and Powerstock calorifier installation manual 500001084.

Features

■■ No burner—Heat exchanger coils supplied by external heat source(s) heat the stored water

■■ Twin coils for independent external heat sources


■■ Controls: control and limit stats to control DHW flow temp via a three-port valve (not HHL supply)


■■ Clean out door■■ Kit to connect twin coils in series

■■ Immersion heater kit options

ExceedsMinimum

Requirements

Offering a flexible approach to indirect heating and storage, Powerstock calorifiers can be easily coupled to any heating boiler or renewable energy source to provide highly efficient hot water generation.


■■ Capacities 160–958 litres

W D

H

Specification

Powerstock Calorifier PS Model

PS160Single

coil

PS200 Single

coil

PS300 Twin coil

PS400 Twin coil

PS500 Twin coil

PS750 Twin coil

PS1000 Twin coil

Wate

r



Storage capacity l 160 200 292 380 470 731 958


Maximum operating water pressure, unvented water supply bar 3.5 bar (as per preset pressure reducing valve setting in unvented kit)

Maximum water temperature °C 110°C (primary coil), 70°C (stored water)

En

erg

y

Input power gross-maximum** (from coil’s heat source eg. boiler/solar) kW 29.2 35.6 61.2 76.2 91.8 85.0 97.0

Output power–maximum approx. kW 29.1 35.5 61.1 76.1 91.7 84.9 96.8

10 min Peak Output, ∆T = 50°C min 250 362 567 889 1077 1319 1483



Heating up time, ∆T = 50°C, with only optional immersion heater 9kW/(4kW) min

54(139)

67 (174)

101 (261)

135(348)

169(435)

253(653)

337(871)

Dim

en

sio

ns

Width (W) mm 540 540 600 700 700 910 1010

Depth (D) mm 607 607 687 767 767 1002 1102

Height (H) mm 1184 1445 1794 1591 1921 1998 2025

Hot water outlet–type/diameter inch R ¾” R 1" R 1¼"

Cold water inlet–type/diameter inch R ¾” R 1" R 1¼"

Coil supply/return–type/diameter inch R 1"

Weight empty kg 70 80 130 185 215 217 275

Power consumption W


http://hamworthy-heating.com/Shared/Files/Powerstock-brochure-2488B.pdf

17

Powerstock TanksHot Water Storage

SpecificationPowerstock Tank ST Model

ST300 ST500 ST750 ST1000

Wate

r/En

erg

y

Storage capacity l 300 502 750 990


Maximum operating water pressure, unvented water supply bar

Typically 3.5 bar (as per primary appliance’s pressure reducing valve setting in associated unvented kit)

Maximum water temperature °C 95°C

Standby losses kW/24h 2.4 3.12 3.6 4.8

Dim

en

sio

ns

Width (W) mm 600 700 910 1010

Depth (D) mm 667 767 1002 1102

Height (H) mm 1794 1921 2023 2040

Hot water outlet (To DHW outlet)–type/diameter inch R 1½" R 2”

Cold water inlet– type/diameter inch R 1" n/a

Tank Charging Outlet (to calorifier)–type/diameter inch R 1½" R 2”

Tank charging inlet (from calorifier)– type/diameter inch R 1½" R 2”

Weight empty kg 87 111 195 248

Power consumption W n/a

Electrical supply VAC n/a

Notes: On ST300 and ST500 tanks, allow clearance of 1300mm above the tank for anode removal/ On ST750 and ST1000 allow clearance of 1300mm in front of side-mounted anodes on ST750 an ST1000. Otherwise allow clearances of 1000mm above water heater, 1000mm around the controls and clean-out doors, and 500mm around all other sides.

*For unvented water supplies use optional unvented kit. For full details, refer to the Powerstock technical brochure 500002488 and Powerstock storage tanks installation manual 500001177.

Features


■■ Controls: control and limit stats to control DHW loading pump (not HHL supply)

■■ Low standing losses■■ Corrosion protection: Magnesium sacrificial anode or optional electrical anode

■■ Clean out door■■ Fully insulated■■ Immersion heater kit options

Powerstock tanks can be easily coupled to any indirect or direct-fired water heater system to augment hot water storage volumes to suit large demand applications.

■■ 4 models ■■ Capacities 300–990 litres

Powerstock OptionsThe following options are available for Powerstock calorifiers and tanks.

■■ Immersion heaters ■■ Unvented supply kit■■ Top-to-bottom recirculation kit■■ Electrical anode protection

With the exception of the immersion heaters, these options are similar to the equivalent options described for the Dorchesters on page 12, but will be specific to Powerstocks.

Immersion Heater Option

Hamworthy can supply an electrical immersion heater as an

option for all Powerstock calorifiers and tanks comprising a replacement stainless steel clean out door and either a 4kW or 9kW immersion heater. As the immersion heater cannot provide the same power as a calorifier coil, heat up times will be extended when relying on the immersion heater alone (See table on page 16).

Please note that with calorifier models PS160 and PS200, it is not possible to have an immersion heater at the same time as using an unvented supply kit, because the anode is relocated to the clean out door position.

The immersion heater can be wired for single phase 230V or three phase 415V.

ExceedsMinimum

Requirements

W D

H

Pow

erst

ock

Cal

orifi

ers

and

Tank

s

http://hamworthy-heating.com/Shared/Files/Powerstock-brochure-2488B.pdf

18

Trigon Solar and Dorchester DR-TCSolar Hot Water Solutions

Trigon Solar and Dorchester DR-TC

Hamworthy offer two distinct solar systems, the Trigon solar system and Dorchester DR-TC solar system, and together these offer several choices to building services engineers who are integrating solar energy into commercial hot water systems.

The Trigon system includes a full range of products to create and control a solar circuit. These include:

■■ Vertical and horizontal orientation high-efficiency collectors which can be connected together in arrays to quickly form a solar collector field,

■■ Modular mounting equipment and fixing kits for rapidly mounting collector arrays on different roof types or on adjustable A-frames for ground mounting,

■■ Choice of three solar transfer stations with highly efficient pumps, expansion vessels, safety equipment and ancillaries,

■■ Choice of basic or advanced electronic solar controllers, and optional monitoring and metering equipment.

In addition, Hamworthy support nine pre-defined Trigon design schemes for rapid design implementation. A Trigon solar circuit is completed by connecting to a coil or coils in one or more Powerstock or equivalent calorifiers.

In contrast, the Dorchester DR-TC system (see page 7 and page 13) is a solar and gas hybrid solution comprising a self-contained solar and gas powered water heater and water storage system with a dedicated solar and gas control system. A solar coil is included in each water heater, and each water heater is supplied with its own dedicated solar transfer station (choice of two) with solar pump and safety equipment.

A Dorchester DR-TC system requires a solar collector field, expansion vessel and some ancillary equipment to complete its solar circuit, all of which may be selected from the Trigon range of solar products.

Trigon solutions are available for single field* or dual field (e.g. an East-West roof system) collector arrangements, in any array combination up to 60m2 area (up to 30 Trigon collectors), whereas the Dorchester DR-TC is for a single field of collectors, in any array combination up to 40m2 (up to 20 Trigon collectors).

Trigon Solar

In Trigon systems solar thermal energy is commonly used via calorifiers, such as Powerstocks, with high efficiency coils to transfer the heat into stored water for distribution around a building. The solar energy can be supplemented through heat from a boiler system, or using an electric immersion heater.

Alternatively, solar thermal energy may be used to pre-heat storage tanks which are used to feed the water supply to conventional direct-fired storage water heaters. This retains the seasonal efficiency benefits of separating the hot water generation from the heating system, and often enables the hot water generation to be located closer to the point of use, further reducing heat losses associated with hot water distribution systems.

Trigon solar hot water systems are designed for integration with the Hamworthy Powerstock twin-coil calorifiers, to provide solar duty domestic hot water (DHW) in systems where one coil in a Powerstock calorifier is fed by the solar circuit and one is fed by hot water from a boiler. Alternatively, it can be used in two–stage DHW systems where, in the first stage, the solar circuit feeds both calorifier coils (with both coils linked in series) to produce the solar pre-heated cold water feed for input to a second stage of DHW heaters. These can be either Dorchester water heaters or further Powerstock calorifiers which subsequently generate the duty DHW output.

Trigon solar systems are an attractive proposition as they profit from “free” solar energy whenever feasible. The more the calorifier is heated by solar energy, the less energy from other means is required to satisfy the heat demand at the DHW output, and so the greater the saving in fossil fuel, and the greater the carbon reduction. Trigon systems become even more attractive when combined with Hamworthy high efficiency gas, oil or biomass boilers for top-up, night time and anti-Legionella purge cycle heating; creating highly cost effective, energy efficient, low carbon emission systems.

Dorchester DR-TC Solar System

Solar thermal energy can also be deployed using the Hamworthy Dorchester DR-TC system which is a hybrid system combining solar heating and condensing direct gas fired heating within a single storage water heater. The Dorchester DR-TC offers a compact, close to point-of-use solution as an alternative to a full Trigon system. Its built-in solar coil, solar transfer station and integrated solar controls work together with a Trigon, or equivalent, field of collectors, to provide solar heating whenever the collector temperature rises to a few degrees above the temperature of the stored water. With solar heating prioritised whenever feasible, gas consumption is minimised and carbon emissions are reduced, making a highly efficient hot water solution.

For more detailed information on the Dorchester DR-TC refer to the Hamworthy Dorchester DR-TC brochure 500002598 and for the Trigon system refer to the Hamworthy Trigon brochure 500002597. These brochures, together with a range of installation and technical guides for these systems are available to download from the Technical Library on the Hamworthy website: www.hamworthy-heating.com.

A block diagram comparing the two systems’ key components is shown on the next page.

Note *A solar field is defined here as an arrangement of one or more collectors, grouped in single or multiple arrays that belong to the same closed solar circuit, and with solar fluid flowing through it controlled by a single pump.

Trigon Solar

A complete package, which delivers everything required for an integrated solar hot water solution.

■■ Vertical or horizontal collectors■■ On-roof or A-frame installation■■ Standard or advanced controls

■■ Integrates with Dorchester water heaters and/or Powerstock calorifiers

http://hamworthy-heating.com/Shared/Files/Dorchester-DR-TC-Brochure-500002598A.pdf


19

Trigon Solar & Dorchester DR-TCSolar Systems Block Diagram

For referenced schemes A to J refer to the Trigon brochure 500002597

DorchesterDR-TC

SolarTransfer

Stations

Dorchester DR-TC Controls

Trigon Controls

Single Field of CollectorsDual Field of Collectors

ST3 STDAdvanced

Solar Transfer Station

ST2 STD

ST1 STDStandard


ST3 ADVAdvanced


ST2 ADVAdvanced


ST1 ADVAdvanced


Solar pre-heated cold water feed

Powerstock calorifiers Ref. Schemes A, B, C & D

Powerstock calorifier + Powerstock water storage tanks

Ref. Schemes E & F

Aux

. Boi

ler Powerstock

calorifiers with solar pre-heated cold water feed Ref. Scheme J

Remote Display

Remote Monitors

Dorchester DR-TCController

Aux

. Boi

ler

Dual aspectroof

Single aspect roof

40%

pro

pyle

ne g

lyco

l/wat

er s

olar

flu

id c

ircui

t

40%

pro

pyle

ne g

lyco

l/wat

er

sola

r flu

id c

ircui

t

Trigon System DR-TC System Dorchester

V40 flowmeter

Dorchester DR-TC

flowmeter

Single Field of Collectors

Trigon SolarTransferStations

1 to 10 collectors per field(max. 20m2 per field), anyarray combination

1 to 30 collectors (60m2 in a single field), any array combination

Trigon Solar Collectors■¬ Trigon Vertical 2.3V■¬ Trigon Horizontal 2.3H

Modular array mounting system, with: ■ On-roof kits, for mounting collectors

in arrays on tiled, slate or corrugated steel sloping roofs Shallow (20° to 45°) or steep (50° to 65°) incline A-frame kits, for flat roof or ground mounting.

■

1 to 15 collectors (max.30m2 in a single field), any array combination

TrigonSolar DutyDHWSystems

TrigonSolarPre-heatDHWSystem

DorchesterDR-TC solarwater heaterwith integratedgas burner

Ref. Brochure500002598

Dorchester DR-LAor equivalentwater heaterswith solar preheatedcold feedRef. SchemesG & H

Solar energyto one coil inPowerstockcalorifier

Solar energy totwo series-linked coils in Powerstockcalorifier

TX1

TX2

SolarTransferStation

ST1 DUAL ADV AdvancedSolar Transfer Station

for dual aspect/dual field (with two pumps, one per aspect/field)

Single aspect roof

WMZ Heat meter

DL2 Datalogger

DL2 Datalogger

Standard ControllerDeltaSol BS/2

Advanced ControllerDeltaSol M

with integral heat meter

Solar DutyDHW System

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Hot Water InformationGeneral InformationControlling Legionella

All Dorchester models are designed to meet the Health & Safety Commission (HSC) requirements for safe production of hot water, and in particular the control of Legionellosis. Legionella bacteria are common in natural water sources and therefore low concentrations may be present in many water systems. It is important that hot water services are designed and operated in such a way that these organisms are prevented from multiplying. Water temperature is a significant factor in controlling the risk, with optimum conditions for bacterial growth occurring between 20°C and 45°C.

Regular cleaning of the system will help to avoid the build-up of sediments, which may harbour or provide nutrients for the bacteria. Water stagnation may encourage the growth of biofilm, which can provide local conditions that may encourage the growth of Legionella bacteria.

Legionella can be safely and easily controlled with good design which takes into account the impact of low flow rates, dead legs and stratification, together with a regular planned cycle of pasteurisation. By raising the temperature of the entire hot water hot water system once per day, to 60°C for 1 hour will effectively control Legionella.

The installation of top-to-bottom recirculation kits on water heaters and tanks is also recommended and these should be set to run during programmed anti-Legionella cycles to prevent stratification and ensure the entire tanks contents is heated to the right temperature is heated. Similarly, system recirculation pumps should be operated at the same time to ensure the whole hot water system is made safe.

In addition, outlets such as taps and shower heads should be regularly operated and cleaned, and records of such maintenance and anti-Legionella schemes in use should be kept by a person designated with that responsibility for the building.

Legionella Prevention vs. Scalding and Limescale Risks

The design of a “safe” hot water system presents conflicting needs, and a compromise is required to strike a balance between the risk of scalding from excessively hot water greater than 55°C and the risk of having a hot water system running at a temperature that encourages the growth, rather than elimination, of Legionella bacteria, and at the same time considers the energy consumption implications.

Both risks could potentially be balanced by setting the water heater’s thermostat to at least 54.4°C as Legionella bacteria cannot survive for a long periods at or above this temperature, however the European Guidelines for Control and Prevention of Travel Associated Legionnaires’ Disease recommend that hot water should be stored at 60°C (140 F) and distributed such that a temperature of at least 50°C and preferably 55°C is achieved within one minute at outlets. The UK HSC’s L8 document: ‘Legionnaire’s disease. The control of Legionella bacteria in water systems‘, states that if temperature is the means for controlling Legionella then “the hot water circulating loop should be designed to give a return temperature of 50°C or above.”

Limescale

Apart from the increased energy consumption, one effect of storing water at 60°C or above is that limescale deposits form more readily, which can provide an environment in which bacteria could thrive. This therefore implies that the higher the storage temperature, the more frequent the inspection and removal of limescale deposits will need to be, and in any case must be carried out as an essential part of the routine maintenance of a water heater as part of its Legionella prevention regime.

Scale should also be regularly removed for other reasons; 1mm of scale build-up can cause up to 7% drop in efficiency in water heaters, and also hot spots may form on heat exchanger surfaces which could cause the heat exchanger to fail.

Thermostatic Control Valves

Another effect of storing water at 60°C or above, and recirculating water at high temperatures, is that such a strategy requires the use of thermostatic controlled valves (TMVs) to guard against any risk of scalding by users.

For commercial and healthcare applications these should be TMV2 or TMV3 WRAS approved valves depending on the application. These are fitted prior to hot water outlets to blend cold water automatically with the hot water to reduce the temperatures to safe levels at the point of use.

The specific hot water outlet temperatures vary depending on the purpose of the hot water and the category of user, with lower temperatures for those considered being in ‘at risk’ groups. The latest version of Building Regulations (Part G, 3.66 - Prevention of Scalding) states: Acceptability of in-line blending valves can be demonstrated by compliance with the relevant European standards EN1111 and EN1287...to demonstrate that the maximum temperature of 48°C cannot be exceeded (note this applies to baths only). Whereas in NHS institutions hot water temperature has to be controlled to maximum temperatures of 41°C for hand washing and showers, 44°C for baths, and up to 46°C for supervised baths.

Local authorities may also refer to Building Bulletin 87, 2nd Edition Guideline for Environmental Design in Schools, which recommends a maximum hot water temperature for school wash basins of 43°C.

Powerstock calorifiers and storage tanks are provided with a control thermostat that may be used to control the primary heat source to achieve the stored water temperature set point. For systems which utilise solar energy to contribute to the heat source, there may be occasions when the desired stored water temperature will be exceeded. It is particularly important for such systems that suitably applied thermostatic mixing valves are fitted at all hot water outlets to ensure that the risk of scalding is reduced.

Further information relating to application requirements can be found at the Thermostatic Mixing Valve Manufacturers Association web site – www.beama.org.uk.

http://en.wikipedia.org/wiki/Legionella

http://www.beama.org.uk

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Hot Water InformationGeneral Information Maintenance

Installed water heaters and calorifiers will experience a wide variation in operating conditions that can occur due to differing patterns of usage and the variable chemical nature of distributed water supplies. It is therefore strongly recommended that water heaters and calorifiers be drained and inspected within 3 months of the initial commissioning.

Once the level of calcium deposition and rate of anode decay are established a suitable maintenance schedule can be implemented, however as a minimum all water heaters and calorifiers should be serviced annually.

Solar circuits must be inspected annually for correct operation of venting points, safety equipment and to check the quality and pressure of the solar fluid. The calibration of optional solar metering systems may need to be checked in line with regulations for claiming renewable heating incentives.

Water Treatment

Due to the variable chemical composition of distributed water supplies it is necessary to identify the properties of the cold water feed to the water heater. In common with all types of water heating equipment, scale will develop during normal use and it is therefore essential that the appropriate steps are taken to ensure reliable and continuous operation of the plant. Contact should be made with the local water provider to determine the quality of the feed water and reference should be made to water treatment specialists for appropriate advice.

Dead Legs

Dead legs to water draw off points should be as short as possible, and not exceed the lengths laid down in the Water Supply (Water Fittings) Regulations 1999, which state that the maximum length of uninsulated pipes supplying a hot water draw off tap measured along the axis of the pipe from the heater, cylinder or tank or from a secondary circuit should be:

Pipe Outside Diameter/mm Max. Dead Leg length/m

≤ 12 20

12-22 12

22-28 8

>28 3

Open-vented Primary Systems—Secondary Hot Water Temperature Control (Calorifiers Only)

Low pressure open vented primary systems are specified as being those where the primary circuit pressures are less than 5metres head at the top of the boiler and/or less than 2.5 metres head at the mid-point of the calorifier primary coils.

Low pressure open vented systems are classified by their design as those that prevent the primary temperature exceeding 100°C in the event of primary circuit temperature control failure. In these systems the calorifier temperature controls can be connected to divert the primary flow or stop the primary pump to prevent excessive heating of the calorifier content. In non-low pressure open vented primary systems where the primary circuit pressures are greater than 5 metres head at the top of the boiler and/or greater than 2.5 metres head at the midpoint of the calorifier coil, the primary temperature is deemed as capable of exceeding 100°C due to operating under pressure. In these systems additional temperature control measures are required to prevent the

calorifier content exceeding 100°C in the event of primary circuit temperature control failure.

Stratification

Stratification is essentially layering of hot and cold water within a water heater, with the hottest water naturally rising to the top of the cylinder and the coldest water collecting at the bottom of the cylinder. This effect can be both desirable and undesirable, and the point of view depends on the circumstances and operational requirements on the cylinder at any given time.

From the anti-Legionella perspective, stratification is to be avoided, and during an anti-Legionella purge cycle, a top-to-bottom recirculation system is run to take hot water from the top of the cylinder back and return it to the cooler base of the water heater, continually mixing the water so that a uniform temperature is maintained throughout. This will prevent a cooler layer of water forming at the bottom of the cylinder that might otherwise not reach the required pasteurisation temperature for the required length of time during an anti-Legionella cycle and so risk creating a region in which Legionella bacteria could thrive.

Stratification is however a useful effect in that it ensures the hottest water is always available at the draw-off point at the top of the tank. Stratification may be useful in solar circuits, where it may be beneficial to have a cooler lower part of the cylinder where the solar coil is located. This is because the solar circuit only operates when the calculated temperature differential (the measured collector temperature minus the store temperature measured at the solar coil) is at, or greater than, the programmed temperature differential (typically 3 to 5°C). Therefore the lower the store temperature in the vicinity of the solar coil, the lower the collector temperature can be for the solar circuit still to operate and input solar energy into the store. Which means that even on cold days with little sunlight, the solar system can make an effective contribution to water heating, helping to drive up system efficiencies and making savings on fossil fuel usage possible all year round.

Air Supply and Ventilation

An adequate supply of fresh air for ventilation must be provided for water heating equipment as well as for combustion air for open vented gas fired appliances, in accordance with BS5440 and BS6644. Refer to specific range brochures for details.

Flues (Dorchester Ranges only)

Dorchester direct-fired water heaters each have flue requirements specific to their range. Hamworthy provide recommended flue terminals for appropriate flue schemes for the Dorchester DR-FC Evo, DR-TC and DR-RS ranges only. Flue terminals for Dorchester DR-SA/SE, DR-LA/LP and DR-PF, and all flue pipework between water heater and terminals are not Hamworthy supply.

However Hamworthy works in partnership with Midtherm Engineering to provide a comprehensive flue design and installation package for all of the Dorchester range of water heaters. Contact your Hamworthy Area Sales Manager about your bespoke flue requirements, and get peace of mind on your next project: Tel: 0845 450 2865 Email: [email protected]

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Hot Water InformationRegulatory InformationInstallationThe installation of all water heaters, calorifiers and storage tanks MUST be in accordance with the relevant requirements of Gas Safety Regulations, I.E.T. Regulations and the bye-laws of the local water undertaking. It should also be in accordance with any relevant requirements of the local gas region, local authority and relevant recommendations of the following documents:

British Standards

BS 5440 Part 1 Flueing and ventilation for gas appliances of rated input not exceeding 70kW net. Installation of gas appliances to chimneys, and for maintenance of chimneys.

BS 5440 Part 2 Flueing and ventilation for gas appliances of rated input not exceeding 70kW net. Installation and maintenance of ventilation provision for gas appliances.

BS 6644: Installation of gas-fired hot water boilers of rated inputs of between 70kW net and 1.8MW net.

BS 6700: Design, installation, testing and maintenance of services supplying water for domestic use.

BS 6798: Installation and maintenance of gas-fired boilers of rated input not exceeding 70kW net.

BS 6880: Part 1, 2 & 3: Code of practice for low temperature hot water heating systems of output greater than 45 kW.

BS 6891: Installation of low pressure gas pipework of up to 28mm in domestic premises.

BS 7074 Part 1: Application, selection and installation of expansion vessels and ancillary equipment for sealed water systems. Part 2: Code of Practice for low and medium temperature hot water heating systems.

BS 7671: Requirements for electrical installations. IET Wiring Regulations. Seventeenth Edition.

BS EN ISO 4126-1: Safety devices for protection against excessive pressure. Safety valves.

BS EN 1111: Sanitary tapware. Thermostatic mixing valves (PN10). General technical specification.

BS EN 1287: Sanitary tapware. Low pressure thermostatic mixing valves (PN10). General technical specifications

BS EN 806-2: Specification for installations inside buildings conveying water for human consumption - Part 2: Design.

BS EN 12828: 2003 Heating systems in buildings. Design for water-based heating systems.

BS EN 14336: 2004 Heating systems in buildings. Installation and commissioning of water based heating systems.

CP 342: Centralised hot water supply. Part 2: Buildings other than individual dwellings.

Building Regulations

The Building Regulations 2000 Approved Document G - Hot Water and Water Efficiency

The Building Regulations 2010 (Revised 2013):

Approved Document L2A 2013 Edition: Conservation of fuel and power (New building other than dwellings)

Approved Document L2B 2010 Edition: Conservation of fuel and power (Existing buildings other than dwellings), and Amendments to the Approved Documents, November 2013.

CIBSE PublicationsCIBSE Guide G: Public Health EngineeringCIBSE TM13: Minimising the risk of Legionnaires’ disease.CIBSE Guide H: Building Control Systems.CIBSE Guide Energy Efficiency in Buildings.CIBSE Commissioning Code B: 2002.

Department of HealthHealth Technical Memorandum 04-01: The control of Legionella, hygiene, ‘safe’ hot water, cold water and drinking water systems. Part A Design, installation and testing. Part B Operational Management Department of Health (DH).

Health and Safety Executive (HSE)L8. Legionnaires’ disease. The control of legionella bacteria in water systems. Approved Code of Practice and guidance on regulationsINDG436 Safe management of industrial steam and hot water boilers BG01 Guidance on Safe Operation of BoilersHSG274 Legionnaires' disease Technical guidance, Part 2. The control of legionella bacteria in hot and cold water systems

European Standards

I. Gas. E. PublicationsIGE/UP/1: Soundness testing and purging of industrial and commercial gas installations.IGE/UP/1A: Soundness testing and direct purging of small low pressure industrial and commercial natural gas installations.IGE/UP/2: Gas installation pipework, boosters and compressors in industrial and commercial premises.IGE/UP/10: Installation of gas appliances in industrial and commercial premises

Statutory InstrumentThe Water Supply (Water Fittings) Regulations 1999Water industry England and Wales.

Third edition of the 1956 Clean Air Act MemorandumDepartment of the Environment, Scottish Development Department & Welsh Office.

Solar Safety (For Trigon and Dorchester DR-TC systems)ENV 1991-2-3 Eurocode 1—Basis of design and actions on structures—Part 2-3: Actions on structures–Snow loads.ENV 1991-2-4 Eurocode—Basis of design and actions on structures—Part 2-4: Actions on structures–wind actions.

COSHHApplicable to storage and use of heat transfer fluid and water treatment chemicals.

Planning Permission for Solar InstallationSeeking the opinion of the local authority on planning matters prior to starting work on a solar installation is advised. However planning permission is generally only required for installations in conservation areas or on listed buildings.

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Hot Water InformationSizing and Hamworthy ServicesHot Water System Sizing Sizing a hot water system requires an understanding of the peak and continuous hot water flow requirements of the application, which is easier to determine in some applications than in others.

A relatively simple example is for an industrial process requiring a specific amount of hot water, in a specified time at a specified temperature. All that is required is the lowest cold water supply temperature and then the heater(s) output can be directly related to the amount of hot water required. If the load is continuous the heater or heaters must be sized to cope with the full amount. If the load is intermittent consideration can be given to a smaller heater installed in conjunction with a suitably sized storage tank.

A more complex but still predictable application might be a sport and leisure facility where a known number of people will use showers, baths etc. at a known time. However with many other commercial and industrial applications the hot water demand can be more difficult to predict, and so a balance may need to be struck between what is the maximum expected demand that the system must satisfy, and for how long it must be sustained at a given temperature.

It is clear that if the water heater can cope with the peak demand, the remaining demand will be adequately catered for. However, the heater would not normally be sized based on all outlet appliances all running at the same time and at their maximum continuous flow rates for a time longer than the peak period duration, as this would result in gross over-sizing of heaters.

To help with sizing, the sizing guidance notes included in the individual Hamworthy Dorchester and Powerstock range brochures list typical flow rates estimates for various outlet types and for different applications.

Having established the number of appliances, the usage, and the quantity of hot water required, the output of the heaters must be related to the hot water storage temperature. Any decrease in the cold water supply temperature or increase in the hot water storage temperature will result in a decreased output from the heater.

Various factors need to be taken into account to determine appropriate storage capacity requirements for the application, and how much if any, additional storage may be required. These include general consumption throughout the day, recovery times, over how many hours the peak load is spread, and whether a larger storage buffer than the water heater’s own storage is required to guard against the possibility of high flow rates at peak times. Any additional storage will require a bronze loading pump to transfer hot water from the water heater into the storage tank.

Solar Circuit SizingIn addition to sizing a hot water system with solar contribution for conditions of no available solar energy, Dorchester DR-TC and Trigon solar systems must be appropriately sized to make best use of the solar energy when it is available. It is not simply a case of maximising the number of collectors to fit the available installation area. On the contrary, there are probably more disadvantages than advantages to having an oversized collector field.

Apart from the additional material cost and increased payback time, having an oversized collector field with too many collectors can result in a system that cannot dissipate

heat to the store faster than it can absorb heat, and when the required store temperature has been satisfied and solar pump consequently switched off, collector temperatures could quickly rise above the stagnation temperature at which the solar fluid boils which can have a detrimental effect on the usable lifetime of the solar fluid, and also put equipment under undesirable thermal stresses.

An undersized solar system, with too few collectors, may make savings in terms of the capital cost of equipment and installation, and there will be a reduced risk of stagnation in the collector field, extending the life of the solar fluid. However overall operating costs will increase as gas usage will be greater than it needs to be to satisfy demand, when compared with a correctly optimised system.

An optimum sized solar system allows for maximum operating time of the solar circuit, which will achieve the best efficiency and return on investment. The solar circuit operation may be set to deliver water at a higher temperature than the gas circuit, and so extend the capacity of the hot water store due to higher resulting mixing requirements at the points of use.

Hamworthy Sizing Support Whether it is for a water heater, calorifier, or solar system, or a DHW system with a combination of heating sources, Hamworthy can assist with sizing and selection of appropriate hot water products to suit the application.

We have extensive knowledge and years of experience in commercial hot water systems we can draw upon to help our customers obtain the appropriate sized solution to suit their needs. We can also assist in the selection and specification of the solar circuit equipment for a specific application based on energy simulation using an industry recognised solar sizing program, which will give results that include projections of solar efficiency, carbon reduction and energy saving.

DeliveryDorchester water heaters and Powerstock calorifiers are delivered factory assembled and mounted within frames, shrink-wrapped and on a timber pallet base. Dorchester DR-FC and DR-RS models are equipped with a steel pallet base which is fitted permanently to the unit. Draught diverters on DR-LA and DR-LP models are supplied packaged separately for fitting on site. Trigon collectors are supplied shrink wrapped on timber pallet base with ancillary equipment boxed separately for fitting on site. All Hamworthy products are delivered to site on a tail-lift vehicle, and deliveries are closely co-ordinated with the customer, to suit the site construction programme. Standard delivery is to ground level from the tail-lift vehicle. All water heaters and calorifiers should be kept vertical when transporting to installation point. To enquire about special delivery services, please contact our customer services team.

Commissioning and ServicingHamworthy Heating Ltd strongly recommends that all water heaters are commissioned by their service department, who will issue an appliance log-book that details the initial operating settings, and which can be used to record all future maintenance work. Service contracts are also available and can be tailored to the requirements of the customer.

For more information on commissioning and service contact Hamworthy Heating Service Department. Tel: 0845 450 2866 Email: [email protected]

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Customer Service Centre

Hamworthy Heating Limited Fleets Corner, Poole, Dorset BH17 0HH

Telephone: 0845 450 2865 Email: [email protected] Web: www.hamworthy-heating.com

Hamworthy reserves the right to make changes and improvements which may necessitate alteration to the specification without prior notice.

Dorchester, Powerstock and Hamworthy are registered trademarks of Hamworthy Heating Limited.

500002371 J

Hamworthy Heating Accreditations

ISO 9001 Quality Management System

ISO 14001 Environmental Management System

OHSAS 18001 Health & Safety Management System

The printed version of this brochure is produced using environmentally friendly print solutions

in partnership with our suppliers

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