A Guide to Commercial Hot Water from Hamworthy

A Guide to Commercial Hot Water
from Hamworthy
Introducing 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
A Guide to Hot Water from Hamworthy
Overview
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
Hamworthy 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: sales@hamworthy-heating.com
Powerstock Storage Tanks . . . . . . 17
Talk to Hamworthy
Powerstock Options . . . . . . . . . 17
With 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.
Trigon Solar & Dorchester DR-TC . 18
Solar Hot Water Solutions . . . . . . 18
General Information . . . . . . . . . 20
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.
Regulatory Information . . . . . . . . 22
Let Hamworthy help you make the right choice.
Solar Systems Block Diagram . . . . . 19
Hot Water Information . . . . . . . 20
Sizing and Hamworthy Services . . . 23
Dorchester DR-FC Evo
Fully Automatic
Condensing, DirectFired 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 l/h
■■ Reduced energy costs
■■ Low noise
■■ Can be
installed
close
to the point
of use
2
Dorchester DR-TC Solar
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 l/h
■■ Saves space
■■ Prioritises
solar
energy
over gas
Dorchester DR-LA/LP
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.
■■ 13 models
■■ Continuous outputs
620–2103 l/h
■■ Permanent pilot option
(DR-LP)
■■ Simplifies installation in
replacement
projects
■■ Horizontal
or vertical
flue
connection
Dorchester DR-RS
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 l/h
■■ Ideal for plant rooms
with restricted
ventilation or locations
without a plant room
Direct and Indirect Solutions
Direct-Fired and Indirect-Fired
Powerstock Indirect-Fired Solutions
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.
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.
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 directfired 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.
Dorchester DR-PF
Power Flame, Gas or
Oil, Direct-Fired Water
Heaters
Dorchester DR-SA/SE
Fully Automatic SingleTube 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.
The lowest output water
heaters in the Dorchester
range, these are ideal for
smaller applications.
■■ 6 models
■■ Continuous outputs
1012–3241 l/h
■■ Greater flexibility with
smaller flue diameter
requirements
■■ Choice of
fuel supply
■■ 4 models
■■ Continuous outputs
369–392 l/h
■■ Permanent pilot option
(DR-SE)
■■ Ultra quiet operation
■■ DR-SE can operate
without an electrical
supply
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 indirectfired 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.
Powerstock
Indirect-Fired Heating
and Hot Water Storage
Trigon Solar
Solar Thermal Hot
Water System
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.
A complete package,
which delivers everything
required for an integrated
solar hot water solution.
Calorifiers
■■ 7 models
■■ Continuous outputs
569–1858 l/h
■■ Capacities
160–958 l
■■ Vertical or horizontal
collectors
■■ On-roof or A-frame
installation
■■ Standard or advanced
controls
■■ Integrates with
Dorchester water
heaters or Powerstock
calorifiers
Storage
Tanks
■■ 4 models
■■ Capacities
300–990 l
3
Dorchester Water Heaters
Introduction
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 preheated water for input to two Dorchester DR-FC Evo 25 water heaters—each fitted with top-to-bottom recirculation kit and unvented kit options.
4
Dorchester Water Heaters
Dorchester Water Heaters
Specification
Construction
All 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.
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.
Burner assembly
Cover
Hot water outlet
Air supply hose
Controller
Pressure switch
Flue gas test point
Control panel
Top store
temperature sensor
Electrical connector
block
Plate heat exchanger
supply (not used)
Anode
Combustion
chamber
Heat exchanger
Mid store
temperature sensor
Tank
Recirculation
connection
Concentric flue pipe
Plate heat exchanger
return (not used)
Condensate trap
Solar coil inlet
Clean out door
Drain valve
Solar heat exchanger
Solar coil
temperature sensor
Base
Cold water inlet
Solar coil outlet
Insulation layer
Cutaway of a Dorchester DR-TC showing a down-firing pre-mix burner and condensing
heat exchanger, with solar coil below.
5
Dorchester DR-FC Evo
Ultra-Quiet
<45dBa
Fully Automatic, Condensing
Direct-Fired Water Heater
Features
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 l/h
■■ Reduced energy costs
■■ Low noise
■■ Can be installed close
to the point of use
W
98%
H
■■ 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
■■ 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
D
Dorchester DR-FC Evo Model
Energy
Water
Specification
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
Continuous output with 44°C ∆Tl/h
600
630
970
1200
1700
2000
2400
Continuous output with 50°C ∆Tl/h
530
560
850
1100
1500
1700
2100
Storage capacity
227
Maximum operating water pressure,
open vented water supply
bar
Maximum operating water pressure,
unvented water supply
bar
NG
LPG
Gas
386
504
8 bar
3.5 bar (=cold feed pressure reducing valve preset in unvented kit option)
Maximum water temperature
°C
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
Heating up time, ∆T = 50°C
min
26
42
27
23
21
18
15
kW/24h
4.2
4.7
4.7
4.7
6.7
6.7
6.7
8.3
10.1
12.3
6.1
7.4
9.0
Standby losses
Dimensions
l
Gas G20 inlet pressure–nominal mbar
Gas G20 flow rate–maximum
@1013.25 mbar and 15°C
m3/h
LPG G31 inlet pressure–nominal mbar
LPG G31 flow rate–maximum
@1013.25 mbar and 15°C
kg/h
80
20
3.1
3.2
5.0
6.0
37
2.3
2.3
3.7
Width (W)
mm
925
Depth (D)
mm
850
Height (H)
mm
1485
4.4
1000
900
2005
2060
Flue spigot diameter
mm
Gas inlet connection–type/diameter
inch
100/150
Rp ¾"
Hot water outlet–type/diameter
inch
R 1½"
Cold water inlet–type/diameter
inch
R 1½"
Weight when empty
kg
202
Power consumption-maximum
W
45
Electrical supply
VAC
130/200
239
45
75
480
115
95
145
240
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.
6
Up to 30kW of
solar heating
Fully Automatic Solar Water Heaters with Integral
Direct-Fired Condensing Gas Burner
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 l/h
■■ Saves space
■■ Prioritises
solar energy
over gas
H
D
W
Water
Energy
DR-TC 40
DR-TC 60
Continuous output with 44°C ∆Tl/h
820
1200
Continuous output with 50°C ∆Tl/h
730
Storage capacity
NG
LPG
Gas
1100
l
Maximum operating water pressure,
open vented water supply
bar
Maximum operating water pressure,
unvented water supply
bar
388
8
3.5 bar (=cold feed pressure reducing valve preset in unvented kit option)
Maximum water temperature
°C
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
min
18
Heating up time, ∆T = 50°C
Standby losses
Solar
■■ 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
Dorchester DR-TC Model
Specification
Dimensions
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
■■ For open vented or unvented*
water supplies
98%
80
13
kW/24h
5.3
Gas G20 inlet pressure–nominal mbar
20
Gas G20 flow rate–maximum
@1013.25 mbar and 15°C
m3/h
LPG G31 inlet pressure–nominal mbar
LPG G31 flow rate–maximum
@1013.25 mbar and 15°C
Maximum pressure, solar circuit
kg/h
4.2
6.0
37
3.1
4.4
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)
Width (W)
mm
850
Depth (D)
mm
925
Height (H)
mm
2055
Flue spigot diameter
mm
100/150
Gas inlet connection–type/diameter
inch
Rp ¾"
Hot/cold water connections–type/diameterinch
R 1½"
Solar coil supply/return–type/diameter
Rp 1"
inch
Weight when empty
kg
Power consumption-maximum
W
Electrical supply
VAC
245
60 + solar control (max 700)
120 + solar control (max 700)
230 V 1Ph 50Hz
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.
7
Dorchester Water Heaters
Dorchester DR-TC
Dorchester DR-LA/DR-LP
Easy fit replacement
water heater for open
flued applications
Fully Automatic Multiple-Tube
Direct-Fired Water Heaters
A natural replacement for
existing water heaters,
the Dorchester DR-LA (or
permanent pilot option DR-LP)
is compatible with most
existing flue designs.
■■ 13 models
■■ Continuous outputs
620–2103 l/h
■■ Simplifies installation in
replacement projects
■■ Horizontal or vertical
flue connection
Exceeds
Minimum
Requirements
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
H
W
D
■■ 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
■■ Clean out door
Dorchester DR-LA/LP Model
Energy
Water
Specification
NG
LPG
Gas
DR-LA
110
Continuous output with 44°C ∆Tl/h
620
819
964
1197
1425
1836
2103
Continuous output with 50°C ∆Tl/h
545
721
848
1053
1254
1615
1851
Storage capacity
324
374
312
351
291
265
264
l
Maximum operating water pressure,
open vented water supply
bar
Maximum operating water pressure,
unvented water supply
bar
8
3.5 bar (=cold feed pressure reducing valve preset in unvented kit option)
Maximum water temperature
°C
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
Heating up time, ∆T = 44°C
min
31
27
19
17
12
8
7
Heating up time, ∆T = 50°C
min
35
31
22
20
14
10
8
15.7
17.2
18.6
22.4
24.1
29.8
60.0
9.4
12.1
13.7
6.4
8.1
9.3
Standby losses
Dimensions
DR-LA/LP DR-LA/LP DR-LA/LP DR-LA/LP DR-LA/LP DR-LA/LP
30
40
45
60
75
95
kW/24h
Gas G20 inlet pressure–nominal
mbar
Gas G20 flow rate–maximum
@1013.25 mbar and 15°C
m3/h
LPG G31 inlet pressure–nominal
mbar
LPG G31 flow rate–maximum
@1013.25 mbar and 15°C
kg/h
Width (W) (with 45° draft diverter)
mm
Depth (D) (with 45° draft diverter)
mm
Height (H) (with 45° draft diverter)
mm
73
20
4.0
5.4
6.3
7.9
37
2.7
3.7
4.5
5.6
710
745
800
1900
2100
1900
Flue spigot diameter
mm
Gas inlet connection–type/diameter
inch
Hot water outlet–type/diameter
inch
Rp 1 ½"
Cold water inlet–type/diameter
inch
R 1 ½"
Weight when empty
kg
Power consumption
W
Electrical supply
150
2040
2000
180
2025
225
Rp ¾"
195
221
209
VAC
2085
Rp 1"
238
30
244
270
329
60
230 V 1Ph 50Hz
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.
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, refer to the Dorchester DR-LA/LP technical brochure 50002519.
8
Easy fit replacement
water heater for room
sealed applications
Room Sealed, Fully Automatic
Direct-Fired Water Heaters
Features
Dedicated room sealed
water heater range
with multi-tube heat
exchanger.
■■ 5 models
■■ Continuous outputs
507–1960 l/h
■■ Ideal for plant rooms
with restricted
ventilation or
locations without a
plant room
■■ 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
H
D
Dorchester DR-RS Model
Water
Energy
DR-RS 25
DR-RS 40
DR-RS 65
DR-RS 85
Continuous output with 44°C ∆Tl/h
507
811
1293
1740
1960
Continuous output with 50°C ∆Tl/h
446
714
1138
1531
1725
Storage capacity
324
312
265
265
265
NG
LPG
l
Maximum operating water pressure,
open vented water supply
bar
Maximum operating water pressure,
unvented water supply
bar
DR-RS 105
8
3.5 bar (=cold feed pressure reducing valve preset in unvented kit option)
Maximum water temperature
°C
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
73
Heating up time, ∆T = 44°C
min
38
23
12
9
8
Heating up time, ∆T = 50°C
min
43
26
14
10
9
kW/24h
9.0
10.4
8.3
9.0
9.9
10.8
12.2
7.9
No LPG variant,
Natural gas
only
Standby losses
Gas
■■ Controls: ON/OFF, thermostat
(control, limit and safety), power
indicator, lockout and reset, volt
free-contacts
■■ Corrosion protection:
Magnesium sacrificial anode or
optional electrical anode
■■ Clean out door
W
Specification
Dimensions
Exceeds
Minimum
Requirements
Gas G20 inlet pressure–nominal mbar
Gas G20 flow rate–maximum
@1013.25 mbar and 15°C
m3/h
LPG G31 inlet pressure–nominal mbar
LPG G31 flow rate–maximum
@1013.25 mbar and 15°C
kg/h
Width (W)
mm
Depth (D)
mm
Height (H)
mm
Flue spigot diameter
mm
Gas inlet connection–type/diameter
inch
20
3.1
5.0
7.9
37
2.2
3.4
5.5
755
1000
1995
80/125
2020
100/150
130/200
Rp 1”
Hot water outlet–type/diameter
inch
Rp 1½"
Cold water inlet–type/diameter
inch
Rp 1½"
Weight when empty
Power consumption
Electrical supply
kg
2 x 130 (twin duct)
Rp ¾"
230
W
245
295
100
VAC
320
320
275
300
230 V 1Ph 50Hz
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 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.
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, refer to the Dorchester DR-RS technical brochure 500002629.
9
Dorchester Water Heaters
Dorchester DR-RS
Dorchester DR-PF
Rapid recovery:
Only 6 mins for
DR-PF 145
Power flame, Gas or Oil, Direct-Fired
Fully Automatic Water Heaters
Features
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.
■■ 6 models
■■ Continuous outputs
965–2816 l/h
■■ Greater flexibility with
smaller flue diameter
requirements
■■ Choice of fuel supply
W
Dorchester DR-PF Model
Energy
Water
Specification
DR-PF 55
DR-PF 65
DR-PF 75
DR-PF 95
DR-PF 115
DR-PF 145
Continuous output with 44°C ∆Tl/h
965
1207
1448
1850
2172
2816
Continuous output with 50°C ∆Tl/h
850
1062
1274
1628
1911
2478
Storage capacity
NG
LPG
Oil
l
Maximum operating water pressure,
open vented water supply
bar
Maximum operating water pressure,
unvented water supply
bar
338
333
296
271
8
3.5 bar (=cold feed pressure reducing valve preset in unvented kit option)
Maximum water temperature
°C
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
kW/24h
8.7
8.7
8.7
8.7
8.7
8.7
12.2
14.3
18.5
Standby losses
Gas and Oil
reset. Air and gas proving
■■ Power flame Riello burner
switches
■■ Fully automatic ignition with
■■ Combustion products safety
flame detection
discharge device
■■ Natural Gas, LPG or Oil
■■ Corrosion protection:
■■ For B23 open flue schemes*
Magnesium sacrificial anode
■■ For open vented or
or optional electrical anode
unvented** water supplies
■
■
Clean out door
■■ Controls: ON/OFF, thermostat
(control, limit and safety),
power indicator, lockout and
H
D
Dimensions
Exceeds
Minimum
Requirements
Gas G20 inlet pressure–nominal mbar
Gas G20 flow rate–maximum
@1013.25 mbar and 15°C
m3/h
LPG G31 inlet pressure–nominal mbar
LPG G31 flow rate–maximum
@1013.25 mbar and 15°C
kg/h
Oil flow rate–maximum, with
maximum viscosity@20°C=6mm2/skg/h
80
20
6.3
7.9
9.5
37
4.7
5.8
7.0
8.9
10.5
13.6
5.3
6.3
7.4
9.5
11.6
16.9
Width (W)
mm
Depth (D) (excluding burner)
mm
Height (H)
mm
Flue spigot dia. (without adaptors)
mm
Gas inlet connection–type/diameter
inch
Rp ¾"
Hot water outlet–type/diameter
inch
Rp 1½"
Cold water inlet–type/diameter
inch
Weight when empty
Power consumption
Electrical supply
705
725
1900
150***
1990
200
250***
Rp 1½"
kg
230
W
180
VAC
240
265
385
305
390
230 V 1Ph 50Hz
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.***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.
10
Fully Automatic Single-Tube
Direct-Fired Water Heaters
H
D
Water
Energy
NG
LPG
■■ Controls: ON/OFF, thermostat
(control and safety),
lockout and reset. Power
indicator (DR-SE only)
■■ Combustion products safety
discharge device
■■ Corrosion protection:
Magnesium sacrificial anode or
optional electrical anode
■■ Clean out door
Dorchester DR-SA/SE Model
DR-SA/SE 16
DR-SA/SE 19
Continuous output with 44°C ∆Tl/h
369
392
Continuous output with 50°C ∆Tl/h
325
345
Storage capacity
278
372
l
Maximum operating water pressure,
open vented water supply
bar
Maximum operating water pressure,
unvented water supply
bar
8
3.5 bar (=cold feed pressure reducing valve preset in unvented kit option)
Maximum water temperature
°C
80
80
Input power, gross–maximum
kW
24.7
26.2
Output power–maximum
kW
18.9
20.1
Heating up time, ∆T = 44°C
min
45
57
Heating up time, ∆T = 50°C
min
51
65
Standby losses
Gas
■■ Atmospheric burner
■■ Ignition: Fully automatic
with flame detection (DRSA) 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
W
Specification
Dimensions
Exceeds
Minimum
Requirements
Features
The lowest output water
heaters in the Dorchester
range, these are ideal for
smaller applications.
■■ 4 models
■■ Continuous outputs
369–392 l/h
■■ Permanent pilot option
(DR-SE)
■■ Ultra quiet operation
■■ DR-SE can operate
without an electrical
supply
DR-SE
Needs no power
supply
kW/24h
Gas G20 inlet pressure–nominal mbar
Gas G20 flow rate–maximum
@1013.25 mbar and 15°C
m3/h
LPG G31 inlet pressure–nominal mbar
LPG G31 flow rate–maximum
@1013.25 mbar and 15°C
kg/h
Width (W)
mm
11.3
N/A
20
2.4
2.5
37
1.6
1.8
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)
VAC
230 V 1Ph 50Hz
230 V 1Ph 50Hz***
Electrical supply
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. *** Basic DR-SE requires no power
supply—230V mains supply only required if any electrical options are to be used.
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, refer to the Dorchester DR-SA/SE technical brochure 500002630.
11
Dorchester Water Heaters
Dorchester DR-SA/DR-SE
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
12
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.
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.
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,
Typical top-to-bottom recirculation kit
Including DR-TC Solar Options
Close Temperature Control Kit
(DR-LA and DR-RS only)
For applications requiring above
average temperature control, an
optional electronic thermostat kit
can be fitted. This will provide close
control of the flow temperature within
±2.5°C, dependant on the operating
conditions.
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 antifreeze
protection to -18°C.
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.
Close temperature control kit
Time Clock Control (DR-SE only)
Dorchester TX1 solar transfer station
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.
An array of two Trigon 2.3V solar collectors
Remote Monitor/BMS Interface
(DR-FC Evo/DR-TC only)
Dorchester Solar Transfer Stations
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
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
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
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.
13
Dorchester Water Heaters
Dorchester Options
Dorchester Water Heaters
Range & Model Comparisons
Key to Tables
Dorchester DR-SA/SE
Dorchester DR-TC
Dorchester DR-PF
HeaterDR-FC
Models
by Increasing
Output DR-RS
Power
Dorchester DR-LA/LPDorchester Water
Dorchester
Evo
Dorchester
Table 1. Dorchester Water Heaters in Order of Increasing Maximum Output Power (kW)
160.0
144.1
Max. Output Power / kW
140.0
120.0
100.0
80.0
60.0
40.0
20.0
18.9 20.1
31.7 32.0
25.9 30.5
41.5 41.9 41.9
49.3 49.3 49.4
66.2
59.3 59.3 61.2 61.7
72.9 74.1
82.6
89.0
100.3
93.9 94.7 98.7
107.6 111.1
119.4
Dorchester Water Heater Models by Increasing Continuous Output
0.0
Dorchester Models
Table 2. Dorchester Water Heaters in Order of Increasing Maximum Continuous Outputs (Litres/Hour)
2816
Max. Continuous Output / Litre/hour
3000
2400
2500
2000
1700 1740
1500
1293
1197 1200 1200 1207
1000
500
369
392
507
600
620
630
811
819
820
964
965
1836 1850
1960 2000
2103 2172
1425 1448
970
Dorchester Water Heater Models by Increasing Recovery Time
0
Dorchester Models
Table 3. Dorchester Water Heaters in Order of Increasing Recovery Time (Minutes)
57
Max. Recovery Time / Minutes
60
50
45
37
40
30
20
10
6
7
8
8
8
9
10
11
12
12
13
14
16
16
17
17
19
19
20
21
23
23
24
27
38
31
Dorchester Water Heater Models by Increasing Storage Volume
0
Dorchester Models
Table 4. Dorchester Water Heaters in Order of Increasing Maximum Storage Volume
600
Max. Storage Volume / Litre
504
500
400
300
227
264
265
265
265
265
271
278
291
296
296
312
312
324
324
333
200
100
0
Dorchester Models
14
338
338
351
372
374
386
386
386
388
388
504
504
Powerstock Calorifiers and Tanks
The efficient generation of hot water for use in commercial
buildings can be achieved using direct or indirect-fired heating
solutions.
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.
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.
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.
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.
Seven models available in the Powerstock range of calorifiers
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 prewired 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-tobottom pump recirculation kit, electrical anode protection and
an electric immersion heater.
Twin coils in Powerstock calorifiers enable two independent energy
sources to be used to heat a common store.
15
Powerstock Calorifiers and Tanks
Introduction
Powerstock Calorifiers
Exceeds
Minimum
Requirements
Indirect-Fired Heating and Hot Water Storage
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.
■■ 7 models
■■ Continuous outputs
501–1635 l/h
■■ Capacities
160–958 l
Features
■■ No burner—Heat exchanger
coils supplied by external heat
source(s) heat the stored water
■■ Twin coils for independent
external heat sources
■■ For open vented or unvented*
water supplies
■■ Controls: control and limit
stats to control DHW flow
temp via a three-port valve
(not HHL supply)
H
W
■■ Corrosion protection:
Magnesium sacrificial anode or
optional electrical anode
■■ Clean out door
■■ Kit to connect twin coils in
series
■■ Immersion heater kit options
D
Powerstock Calorifier PS Model
PS160
Single
coil
PS200
Single
coil
PS300
Twin coil
PS400
Twin coil
PS500
Twin coil
PS750
Twin coil
PS1000
Twin coil
Continuous output with 44°C ∆Tl/h
569
682
1173
1460
1760
1627
1858
Continuous output with 50°C ∆Tl/h
501
600
1032
1285
1549
1432
1635
Storage capacity
160
200
292
380
470
731
958
Water
Specification
Maximum operating water pressure,
open vented water supply
bar
Maximum operating water pressure,
unvented water supply
bar
Energy
Maximum water temperature
10 bar
3.5 bar (as per preset pressure reducing valve setting in unvented kit)
°C
Input power gross-maximum** (from
coil’s heat source eg. boiler/solar)
kW
Output power–maximum approx.
110°C (primary coil), 70°C (stored water)
29.2
35.6
61.2
76.2
91.8
85.0
97.0
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
min
20
20
17
18
18
31
36
kW/24h
1.44
1.92
2.4
2.9
3.12
3.6
4.8
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)
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
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
Standby losses
Dimensions
l
Weight empty
kg
Power consumption
W
Electrical supply
VAC
2025
R 1"
70
80
130
185
215
217
275
230 V 1Ph 50Hz
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 50002488.
16
Powerstock Tanks
Exceeds
Minimum
Requirements
Hot Water Storage
Features
■■ For open vented or unvented*
water supplies
■■ 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
H
■■ 4 models
■■ Capacities
300–990 l
W
D
Powerstock Tank ST Model
Specification
Water/Energy
Storage capacity
l
ST300
ST500
ST750
ST1000
300
502
750
990
Maximum operating water pressure,
open vented water supply
bar
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)
°C
95°C
Maximum water temperature Standby losses
Width (W)
Dimensions
■■ Clean out door
■■ Fully insulated
■■ Immersion heater kit options
10 bar
kW/24h
2.4
3.12
3.6
4.8
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/diameterinch
Cold water inlet– type/diameter
inch
R 1½"
R 2”
R 1"
n/a
Tank Charging Outlet (to calorifier)
–type/diameterinch
R 1½"
R 2”
Tank charging inlet (from calorifier)–
type/diameterinch
R 1½"
R 2”
Weight empty
kg
Power consumption
W
n/a
VAC
n/a
Electrical supply
87
111
195
248
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. or full details, refer to the Powerstock technical brochure 50002488.
Powerstock Options
The following options are available for Powerstock calorifiers
and tanks.
■■ Immersion heaters
■■ Unvented supply kit
■■ Top-to-bottom recirculation kit
■■ Electrical anode protection
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).
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.
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.
Immersion Heater Option
The immersion heater can be wired for single phase 230V or
three phase 415V.
Hamworthy can supply an electrical immersion heater as an
17
Powerstock Calorifiers and Tanks
Powerstock tanks can
be easily coupled to
any indirect or directfired water heater
system to augment hot
water storage volumes
to suit large demand
applications.
Trigon Solar and Dorchester DR-TC
Solar Hot Water Solutions
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
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.
For more detailed information on the Trigon system refer to
the Hamworthy Trigon brochure: 500002597.
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.
18
Trigon Solar & Dorchester DR-TC
Solar Systems Block Diagram
Dorchester
Trigon System
DR-TC System
Dual Field of Collectors
Single Field of Collectors
Single Field of Collectors
1 to 10 collectors per field
(max. 20m2 per field), any
array combination
1 to 30 collectors (60m2 in a single field),
any array combination
1 to 15 collectors (max.30m2 in a
single field), any array combination
Trigon Solar Collectors
Single
aspect
roof
Dual aspect
roof
Single
aspect
roof
■¬
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.
40% propylene glycol/water
solar fluid circuit
40% propylene glycol/water
solar fluid circuit
Standard Controller
DeltaSol BS/2
WMZ Heat meter
Solar
Transfer
Station
DL2 Datalogger
ST3 ADV
Advanced
ST2 ADV
Solar
Advanced
ST1
ADV
Transfer
Solar
Advanced
Station
Transfer
Solar
Station
Transfer
Advanced Controller
DeltaSol M
with integral heat meter
DL2 Datalogger
Station
TX2
Dorchester DR-TC Controls
ST1 DUAL ADV Advanced
Solar energy to
two series-linked coils
in Powerstock
calorifier
Dorchester
DR-TC
flowmeter
Remote Display
Powerstock
calorifiers
Ref. Schemes
A, B, C & D
Dorchester
DR-TC solar
water heater
with integrated
gas burner
Solar Duty
DHW System
Powerstock calorifier +
Powerstock water storage tanks
Ref. Schemes E & F
Dorchester DR-LA
or equivalent
water heaters
with solar
preheated
cold feed
Ref. Schemes
G&H
Ref. Brochure
500002598
Aux. Boiler
Aux. Boiler
Trigon
Solar
Pre-heat
DHW
System
Solar
Transfer
Station
Remote Monitors
V40
flowmeter
Solar energy
to one coil in
Powerstock
calorifier
TX1
Dorchester DR-TC
Controller
Solar Transfer Station
for dual aspect/dual field (with two
pumps, one per aspect/field)
Trigon
Solar Duty
DHW
Systems
Dorchester
DR-TC
Solar
Transfer
Stations
Trigon/Dorchester DR-TC Solar
Trigon Controls
Trigon Solar
Transfer
ST3 STD
Stations
Advanced
ST2
STD
Solar
ST1 STD
Transfer
Standard
Station
Powerstock
calorifiers with
solar pre-heated
cold water feed
Ref. Scheme J
Solar pre-heated cold water feed
For referenced schemes A to J refer to the Trigon brochure 500002597
19
Hot Water Information
General Information
Controlling Legionella
Limescale
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.
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.
Regular cleaning of the system will help to avoid the buildup 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.”
20
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.
Hot Water Information
General Information
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-tobottom 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: sales@hamworthy-heating.com
21
Hot Water General Information
Maintenance
Hot Water Information
Regulatory Information
Installation
Department of Health
The 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 byelaws 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:
Health 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).
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
CIBSE Publications
CIBSE Guide G: Public Health Engineering
CIBSE TM13: Minimising the risk of Legionnaires’ disease.
CIBSE Guide H: Building Control Systems.
CIBSE Guide Energy Efficiency in Buildings.
CIBSE Commissioning Code B: 2002.
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Health & Safety Commission (HSC)
L8. Approved Code of Practice & Guidance—Legionnaires’
disease The control of Legionella bacteria in water systems.
Health and Safety Executive
Guidance note PM5—Automatically controlled steam and hot
water boilers.
European Standards
I. Gas. E. Publications
IGE/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 Instrument
The Water Supply (Water Fittings) Regulations 1999
Water industry England and Wales.
Third edition of the 1956 Clean Air Act
Memorandum
Department 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.
COSHH
Applicable to storage and use of heat transfer fluid and water
treatment chemicals.
Planning Permission for Solar Installation
Seeking 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.
Hot Water Information
Sizing and Hamworthy Services
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 oversizing 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 Sizing
In 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.
Delivery
Dorchester 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 Servicing
Hamworthy 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: service@hamworthy-heating.com
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Hot Water General Information
Hot 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.
Hamworthy Heating Accreditations
ISO 9001 Quality Management System
Customer Service Centre
Hamworthy Heating Limited
Fleets Corner, Poole,
Dorset BH17 0HH
Telephone: 0845 450 2865
Email: sales@hamworthy-heating.com
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.
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