Wimborne GM series Instruction Manual

IMPORTANT NOTE
THESE INSTRUCTIONS MUST BE READ
AND UNDERSTOOD BEFORE INSTALLING,
COMMISSIONING, OPERATING OR
SERVICING EQUIPMENT
Wimborne GM Boilers
Gas/Oil Fired Cast Iron Sectional Boilers
420kW to 1070kW
Installation, Commissioning
and Servicing Instructions
NATURAL GAS
I
2H
CLASS D (35 sec fuel oil)

Technical Enquiries 01202 662527/662528
To supplement the detailed technical brochures, technical advice on the application and use of products in the
Hamworthy Heating range is available from our technical team in Poole and our accredited agents.
Site Assembly 01202 662555
Hamworthy offer a service of site assembly for many of our products in instances where plant room area is restricted.
Using our trained staff we offer a higher quality of build and assurance of a boiler built and tested by the manufacturer.
Commissioning 01202 662555
Commissioning of equipment by our own engineers, accredited agents or specialist sub – contractors will ensure the
equipment is operating safely and efficiently.
Maintenance Agreements 01202 662555
Regular routine servicing of equipment by Hamworthy service engineers inspects the safety and integrity of the plant,
reducing the risk of failure and improving performance and efficiency. Maintenance agreements enable our customers to
plan and budget more efficiently.
Breakdown service, repair, replacement 01202 662555
Hamworthy provide a rapid response breakdown, repair or replacement service through head office at Poole and accred-
ited agents throughout the UK.
Spare Parts 01202 662525
A comprehensive spare parts service is operated from our factory in Poole, providing replacement parts for both current
and discontinued products. Delivery of parts and components is normally from stock within seven days. However, a next
day delivery service is available for breakdowns and emergencies.
Customer Services

HAMWORTHY HEATING LTD Page 500001113/D
Wimborne GM
Wimborne GM Boilers
Gas/Oil Fired Cast Iron Sectional Boilers
420kW to 1070kW
Installation, Commissioning
and Servicing Instructions
NATURAL GAS
I
2H
CLASS D (35 sec fuel oil)
THE WIMBORNE BOILER IS INTENDED FOR USE AS A COMMERCIAL APPLIANCE.
THE GAS FIRED VARIANTS ARE FOR USE ON GROUP H NATURAL
GAS (2ND FAMILY) I2H . THE OIL FIRED VARIANTS ARE FOR USE ON
CLASS D (35 sec FUEL OIL). PLEASE ENSURE RELEVANT
INFORMATION REQUIRED WITHIN DOCUMENT IS FOUND
RELATING TO SPECIFIC FUEL TO BE FIRED BEFORE OPERATING
THE BOILER.
PUBLICATION NO. 500001113
ISSUE 'D’
FEBRUARY 2005
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CONTENTS PAGE
1.0 INTRODUCTION 1
1.2 Packing Lists
1.3 Sectional Boilers
1.4 Hydraulic Testing
1.5 Boiler Set
1.6 COSHH Information
2.0 TECHNICAL DATA 4
3.0 GENERAL REQUIREMENTS 6
3.1 Related documents
3.2 Feed water quality
3.3 Adequate water flow
3.4 Time clock control
3.5 Minimum system water pressure
4.0 LOCATION 7
5.0 GAS/OIL SUPPLY 8
5.1 Gas Service pipes
5.2 Gas Meters
5.3 Gas supply pipes
5.4 Boosted Gas supplies
5.5 Boiler house Gas control valve
5.6 Oil supply
6.0 FLUE SYSTEM 9
6.1 General requirements
6.2 Design waste gas volume and temperature
6.3 Materials
6.4 Suction
6.5 Disconnection
6.6 Flue discharge
6.7 Surface temperature
6.8 Flue system location
6.9 Condensate discharge
7.0 AIR SUPPLY 10
7.1 Air supply by natural ventilation
7.2 Air supply by mechanical ventilation
8.0 WATER CIRCULATION SYSTEM 11
8.1 General
8.2 Pressure relief valve
8.3 Open vent and cold feed pipe
8.4 Altitude gauge (Water pressure gauge)
8.5 Thermometer
8.6 Drain valves
8.7 Circulating pump
8.8 Minimum water flow rates
8.9 Waterside pressure drop
8.10 Control schemes
8.11 Unvented systems
8.12 Modular boiler control schemes
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CONTENTS PAGE
9.0 ELECTRICAL SUPPLY 13
9.1 Site wiring
9.2 Indication signals and volt free contacts
10.0 BOILER ASSEMBLY AND INSTALLATION 17
10.1 Preparation
10.2 Dismantling
10.3 Assembly of boiler casing
10.4 Fitting the Burner
11.0 COMMISSIONING AND TESTING 22
11.1 Electrical installation
11.2 Gas installation
11.3 Water circulation system
11.4 Commissioning the boiler
11.5 External Controls
11.6 Installation noise
11.7 Users instructions
12.0 FAULT FINDING 26
13.0 SERVICING 26
13.1 Initial Inspection
13.2 Burner Service Procedure
13.3 Boiler Service Procedure
14.0 REPLACEMENT OF FAILED COMPONENTS 27
14.1 Control & High / Low Thermostat/s
14.2 Temperature Limiter (Limit Thermostat)
15.0 RECOMMENDED SPARES 29
FIGURES PAGE
Figure A Typical schematic boiler installation layout 3
Figure B Performance and General Information 4
Figure C Boiler Dimensions 5
Figure D Water Connections 5
Figure E Mechanical ventilation flow-rates 10
Figure F Cold feed and vent pipe sizes 11
Figure G Control panel wiring details (High/ Low Burner Control) 14
Figure H Composition of sections within heat exchanger 15
Figure I Composition of heat exchanger assembly—exploded view 15
Figure J Applying the sealant 16
Figure K Composition of Boiler casing assembly 23
Figure L Exploded view of boiler 28
Figure M Matched burner/ boiler combinations gas 33
Figure N Matched burner/ boiler combinations oil 34
Figure O.1 Riello Oil nozzle selection 35
Figure O.2 Nu-Way Oil nozzle selection 35
Figure P Combustion target Figures 36
Figure Q Combustion chamber and burner data 36
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1.0 INTRODUCTION
1.1 Boiler Range
The Wimborne GM boiler range consists of 10 gas or
oil fired cast iron sectional boilers with outputs
ranging from 420kW to 1130kW. Refer to Section
2.0 for details on Natural Gas and Oil firing.
Wimborne GM boilers can be used individually, or in
a multi-boiler configuration, and are suitable for use
on either open-vented or sealed low temperature hot
water heating systems. For hot water production they
can be used in conjunction with calorifiers or indirect
hot water cylinders.
Portland pressurisation units are available from
Hamworthy Heating Ltd for sealed systems.
1.2 Packing Lists
Packing List
Accessory Pack
1.3 Sectional Boilers
Wimborne GM sectional boilers are supplied ready
for on-site assembly.
The heat exchanger consists of:
a. A front section
b. Plain intermediate sections.
c. A rear section
These sections are connected to each other using
nipples and ‘O’ rings and are held together by short
lacing bolts.
The section to section flue gas seal is made by a
mastic strip located in a groove around the inner and
outer perimeter of each section.
The boilers are of the reverse flame design with the
first two passes in the combustion chamber. The final
pass uses turbulator tubes to increase the heat
exchange area and thus enhance thermal efficiency
in use.
Burner Model - Packing List Quantities
GM
6 7 8 9 10 11 12 13 14 15
Intermediate
section 4 5 6 7 8 9 10 11 12 13
Front
section 1 1 1 1 1 1 1 1 1 1
Rear
section 1 1 1 1 1 1 1 1 1 1
Rear flue cover
250mm dia. 1 1 1 1 - - - - - -
Rear flue cover
350mm dia. - - - - 1 1 1 1 1 1
Hinged
front door 1 1 1 1 1 1 1 1 1 1
Casing
pack 1 1 1 1 1 1 1 1 1 1
Insulation
Pieces 1 1 1 1 1 1 1 1 1 1
Flue tube insert
pack (22 off) 1 1 1 1 1 1 1 1 1 1
Control Panel
Assembly. 1 1 1 1 1 1 1 1 1 1
Installers Guide
500001113 1 1 1 1 1 1 1 1 1 1
Accessory
pack 1 1 1 1 1 1 1 1 1 1
Description
Burner Model - Accessory Pack Quantities
GM
6 7 8 9 10 11 12 13 14 15
Guide
Ring 10 12 14 16 18 20 22 24 26 28
`O` Ring
7.3mm 10 12 14 16 18 20 22 24 26 28
Boiler
Cement
Pack
5 5 6 7 8 9 10 10 11 11
Silicon
Sealant
Tube
9 11 12 13 15 16 18 19 20 21
Primer -
Silicon 2 2 2 3 3 3 3 3 4 4
Tie Bolt
M12 x 230 20 24 28 32 36 40 44 48 52 56
Self-Tapping
Screw 70 110 110 110 130 130 130 150 150 150
Description
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Wimborne GM boilers have an operating efficiency of
over 82% based on gross CV.
The heat exchanger assembly is completed by cast
iron front and rear combustion chamber plates and
access plates for the cleaning and inspection of the
heat exchanger flue ways (rear only), all of which are
internally lined with a fibre insulation board. The
burner mounts onto the front plate which is hinged,
suitable for left or right hand operation.
The flow and return water connections are located on
top and to the rear of the boiler. Refer to Figure D for
details.
The Wimborne GM boiler is available with high/low
burners for operation on Class D (35 second) fuel
oil, Natural Gas I2H (Second Family).
The boiler is supplied with a pre-wired control panel
which contains:
a. A fuse
b. An illuminated mains on/off switch
c. Boiler control thermostats (On/Off) & (High/Low)
d. Boiler run, (High/Low) and lockout lamps.
e. A temperature limiter (overheat thermostat) to shut
down the boiler should the water temperature in the
heat exchanger exceed 110°C - with manual reset.
f. An overheat lamp
g. A water temperature thermometer (temp. gauge)
h. Flying leads and plugs to connect to the burner
i. Volt free relay contacts for normal run, overheat
and lockout.
The boiler is housed in a powder coated sheet steel
casing which is supplied flat-packed for on-site
assembly. Refer to Section 10.3 for casing assembly
procedure.
1.4 Hydraulic Testing
All Wimborne GM boiler sections are hydraulically
tested, ensuring the Wimborne GM boiler is suitable
for use on systems with maximum working pressures
of up to 6 bar.
1.5 Boiler Set
The boiler is normally supplied as a set of equipment
comprising the following:
a. Cast iron sections mounted on pallets
b. Accessory kit and tie rods
c. Casing panels
d. Insulation blankets
e. Flue tubes - 22 off
f. Control panel
g. Matched burner: fuel oil or gas
h. Burner mounting plate, drilled ready to accept
burner
i. Oil burner nozzle/s where applicable.
1.6 COSHH Information
Irritant
The boiler insulation blankets are non-
carcinogenic, mineral wool fibre, and may
cause inflammation and irritation on
immediate or repeated or prolonged
contact with the skin or if inhaled. The use of suitable
protective clothing is highly recommended. Avoid
contact with skin and direct inhalation
1.6.1 In case of contact with the eyes, rinse
immediately with plenty of water and seek medical
advice.
1.6.2 In case of contact with skin, wash immediately
with plenty of water.
1.6.3 In case of inhalation, retire to clean air supply
and seek medical advice.
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Expansion pipe
valve
Safety
Drain
Feed
pipe
valve
Feed &
expansion
tank
(
alternative
(
valve
Drain
position
Circulation pump
P
gauges
Pressure &
Temperature
T
Valve
Mains water
Float
Automatic
Air Vent
Hamworthy Modular Boilers
Module
1
Module
2
Module
3
Circulation pump
Heating load
Valve
Module
4
T
‘Marshall HE‘
Water Flow
Temperature
Sensor
Temperature Sensor
'Marshall HE‘ Outside Air
Temperature Sensor
'Marshall HE‘ Room
T
T
T
'Hamworthy Marshall HE‘ boiler
Sequence Control System
Figure A - Typical schematic boiler installation layout
T
valve
Safety
Drain
(
alternative
(
valve
Drain
position
Circulation pump
P
gauges
Pressure &
Temperature
Valve
Automatic
Air Vent
Hamworthy Modular Boilers
Module
1
Module
2
Module
3
Circulation pump
Heating load
Valve
Module
4
T
‘Marshall HE‘
Water Flow
Temperature
Sensor
Temperature Sensor
'Marshall HE‘ Outside Air
Temperature Sensor
'Marshall HE‘ Room
T
T
T
Lockshield
valve
Drain
valve
Pressurisation
Hamworthy
Unit
fill line
Tem p o r a ry
Expansion
Air Vent
Automatic
Valve
vessel
valve
check
Double
valve
LockshieldLockshield
valvevalve
Lockshield
Mains water
Boiler Safety Shutdown Circuit Connection
'Hamworthy Marshall HE‘ boiler
Sequence Control System
VENTED SYSTEM
UN-VENTED SYSTEM
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WIMBORNE GM GM6 GM7 GM8 GM9 GM10 GM11 GM12 GM13 GM14 GM15
No. OF SECTIONS 6 7 8 9 10 11 12 13 14 15
BOILER OUTPUT Gas - maximum kW 420 480 550 630 720 800 880 950 1020 1070
INPUT RATE - Natural Gas (G20) m3/h 49.3 56.3 64.6 73.9 84.5 93.9 103.3 111.5 119.7 125.6
BOILER OUTPUT Oil - maximum kW 440 510 580 670 760 840 925 1000 1070 1130
INPUT RATE - Oil (35SR1) l/h 49.7 57.6 65.5 75.7 85.9 94.9 104.5 113.0 120.9 127.7
FLUE DATA
NOMINAL FLUE DIA. mm 258 358
FLUE DRAUGHT REQUIRED
AT BOILER OUTLET
mbar 0.1 - 0.3 suction
in.wg 0.04 - 0.12 suction
COMBUSTION CHAMBER
RESISTANCE
mbar 3.75 3.75 5.5 7.3 5.7 7 6 7.2 5.6 6.2
in.wg 1.5 1.5 2.2 2.9 2.2 2.8 2.4 2.8 2.2 2.4
APPROX. FLUE GAS TEMP (net) °C 200 (Gas) ~ 220 (Oil)
APPROX. FLUE GAS VOLUME
@ NTP (wet) - (m3/h)
Gas 650 776 882 1008 1146 1246 1392 1505 1610 1700
Oil 753 899 1022 1168 1328 1444 1613 1744 1866 1970
GAS DATA consult burner manufacturers manual
WATER DATA
CONNECTIONS - FLOW and RETURN Flanged PN6 80 Flanged PN6 100 Flanged PN6 125
HYDRAULIC RESISTANCE @ 11°C mbar 28 40 50 65 82 110 130 145 150 180
HYDRAULIC RESISTANCE @ 20°C mbar 4.8 6.1 6.8 7.5 8.6 9.8 11 11.5 11.8 12.4
DESIGN FLOW RATE @ 11°C l/m 547 625 717 821 938 1042 1147 1238 1329 1394
MINIMUM FLOW RATE @ 20°C l/m 301 344 394 452 516 573 631 681 731 767
MAXIMUM WATER PRESSURE bar g. 6
MAXIMUM FLOW TEMPERATURE °C 90
MINIMUMRETURN TEMPERATURE °C 50
WATER CONTENT l 285 330 375 420 465 510 555 600 645 690
WEIGHT (FULL) WITHOUT BURNER kg. 1745 1985 2225 2455 2695 2935 3175 3470 3710 3955
DIMENSION - L (boiler overall length) mm 1255 1435 1615 1795 1975 2155 2335 2515 2695 2875
DIMENSION - B (base overall length) mm 970 1150 1330 1510 1690 1870 2050 2230 2410 2590
ELECTRICAL SUPPLY 400V 3 ph 50 Hz (Burner) – 230V 1 ph 50 Hz (Boiler Panel)
Matched Burner - Nuway (Hi/Lo) Gas XGN650 XGN650 XGN
1000
XGN
1000 BG 700 BG 700 BG 700 BG 700 XGN 2100
XGN
2100
Oil NOL
25T
NOL
25T
NOL30
25T
NOL30
25T
NOL50
28T
NOL50
34T
NOL50
34T
NOL50
34T
NOL50
34T
NOL50
34T
Gas Booster Required - ** ** ** **
Matched Burner - Riello (Hi/Lo) Gas RS50 RS70 RS70 RS100 RS100 RS100 RS100 RS100 RS130 RS130
Oil RL50 RL50 RL70 RL70 RL100 RL100 RL100 RL130 RL130 RL130
Gas Booster Required - ** ** ** ** **
CLEARANCES - refer to Figure D.
Riello 670 930 930 930 930 930 930 930 930 930
Nuway 823 975 975 1275 1275 1275 1275 1275 1275 1275
Dimension B - in front of boiler Riello 1080 1340 1340 1340 1340 1340 1340 1340 1340 1340
Nuway 1233 1385 1385 1683 1683 1683 1683 1683 1683 1683
Dimension C - rear of boiler 1000 - all models
Dimension A - side of boiler (see note#)
Figure B - Performance and general information
Note:- For matched burner/boiler combinations refer to Figure M.
For combustion target figures, refer to Figure O.
# if boilers are to be installed adjacent to each other, the minimum spacing can
be reduced to 200mm, provided that the doors hinge in opposite directions.
2.0 TECHNICAL DATA
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4-7 sections
8-11 sections
12-15 sections
12-15 sections
(alternative)
200
100
1405
205 195
258 358
690
L
B
120 110
1070
REAR VIEW SIDE VIEW FRONT VIEW
Clean out covers
Return connection
Flow connection(s)
Drain R ¾
B
CAA
Figure C - Boiler dimensions
Figure D - water connections
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3.0 GENERAL REQUIREMENTS
3.1 Related Documents.
Gas Safety (Installation and Use) Regulations
1994 – (As amended). It is the law that all gas
appliances are installed by competent persons, in
accordance with the above regulations. Failure to
install appliances correctly could lead to prosecution.
It is in your own interest, and that of safety, to ensure
that this law is complied with.
The installation of the boiler MUST be in accordance with
the relevant requirements of the Gas Safety Regulations,
Building Regulations, Fire Regulations, I.E.E. Regulations
and the bylaws of the local water undertaking.
The installation should also be in accordance with any
relevant requirements of the local gas region and local
authority and the relevant recommendations of the
following documents :-
British Standards
BS 5410 Code of practice for oil firing.
Part 2 Installations of 44 kW and above
capacity for space heating, hot water
and steam supply purposes.
BS 5854 Code of practise for flues and flue
structures in buildings.
See paragraph 5 (3.6).
BS 6644 Specification for installation of gas fired
hot water boilers of rated inputs between
60kW & 2MW.
BS 6700 Design, Installation, testing and
maintenance of services supplying water
for domestic use.
BS 6880 Code of practice for low temperature hot
water heating systems of output greater
than 45kW.
Part 1 Fundamentals & design considerations.
Part 2 Selection of equipment.
Part 3 Installation, commissioning and
maintenance.
BS 7074 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 systems.
BS CP342 Code of practice for centralised hot
water supply.
Part 2 Buildings other than individual dwellings.
I. Gas. E. Publications
IGE/UP/1 Soundness testing and purging of
industrial and commercial gas I
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
Pt 1 flued appliances.
Health and Safety Executive
Guidance note PM5 Automatically controlled steam
and hot water boilers.
CIBSE Publications
"CIBSE Guide"
It is impractical in this document to specify all relevant
information, but the following extracts from the above
references are emphasised since failure to comply with
these requirements will almost certainly result in an
unsatisfactory installation.
3.2 Feed Water Quality
If the boiler feed water has a high degree of
hardness, it is recommended that the water be
treated to prevent precipitation of scale or sludge in
the boiler water passageways. Details of additives
can be obtained from any reliable manufacturer of
water treatment products or the local water authority.
It should be noted however, that even if the boiler water is
of average hardness, not requiring treatment, subsequent
draining of the system for repair or constant make-up
water due to an undetected leak will cause additional
deposits and gradual build-up of scale. It is essential
therefore, that leaks are attended to promptly and
draining is kept to an absolute minimum.
It is recommended that the system be flushed out at least
twice before any water treatment is added. If any doubt
exists regarding the internal cleanliness of an old system,
consideration should be given to the fitting of a coarse
filter in the return pipework to the boiler/s.
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3.3 Adequate Water Flow
Care should be taken in the initial design and layout
having due regard for adequate water flow through the
boilers and the influence of the system controls.
It is recommended that the system design should ensure
a minimum return temperature of 50 °C.
If the temperature/flow-rates of the application
cannot meet those given in Figure B, it may be
necessary to incorporate mixing valves and shunt
pumps to ensure that the boiler will operate
satisfactorily. Figure B shows recommended and
minimum water flows required with the associated
pressure losses. The control system and valves,
where fitted, should be regulated to avoid lower flows
occurring.
3.4 Time Clock Control
In order to avoid local overheating and progressive
calcium deposition at zero flow conditions where
boilers are operated from time clocks, provision
should be made for a 5 minute circulating pump
over-run after the last boiler has ceased firing.
NOTE:- Time clocks should not interrupt live, neutral or
earth connections, see Section 9.0: Electrical Supply for
details.
See Figure G for wiring details.
3.5 Minimum System Water Pressure
To comply with guidance note PM5 (Health and Safety
Executive), the minimum pressure requirements at the
boiler are given below as examples :-
1) Single installed boiler running at 82°C flow
temperature. Minimum head required is not less than 2
metres or 0.2 bar.
2) Single installed boiler running at 95°C flow
temperature. Minimum head required = 5.1 metres or
0.5 bar. See Section 8.10.1 for details.
3) Modular boiler installation running at 82°C flow
temperature and 11°C rise across system. Minimum
head required = 4.3 metres or 0.42 bar.
4) Modular boiler installation running at 82°C flow
temperature and 15°C rise across system. Minimum
head required = 9.4 metres or 0.92 bar. See Section
8.11 for Pressurised Water Systems.
4.0 LOCATION
The boiler location must permit the provision of a
satisfactory flue system, and provide adequate space
around the boiler for servicing and air circulation.
Sufficient space must be provided at the front of the
boiler to allow the removal of the burner assembly for
servicing/replacement, and at the rear for installation
of pipes, valves and flue.
Sufficient clearance around the boiler must also be
provided to allow access for servicing. Refer to
Figures C & D for recommended clearances.
The boiler room, or compartment, housing the boiler/
s - whether specifically constructed for the purpose,
or a modification of an existing space - should be in
accordance with the requirements of either BS 6644,
or BS 5410 Part 2, as appropriate.
The compartment housing the boiler must have
permanent air vents communicating directly with the
outside air at both high and low level. Refer to
Section 7.0 for details.
Where a separate purpose built boiler room is not
available, measures should be taken to protect the
boiler or boilers from damage, and the boiler should
be sited such that extraneous material cannot be
stored next to, or against it.
The boiler must be installed on a suitable level non-
combustible surface, capable of withstanding
temperatures of 65°C and able to support the weight
of the boiler (including pipework and ancillary
equipment) when filled with water. A steel sheet can
be placed beneath the boiler cradle to facilitate
movement of the boiler during assembly. The plinth
must be level, non-combustible, 80mm nominal
height, and must be equal in width to the boiler
casing dimensions.
IMPORTANT:- the plinth must not protrude from the
rear of the boiler to enable fitting of the extension
turrets on the rear return connections.
See Figures C & D for plinth dimensions.
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5.0 GAS / OIL SUPPLY
5.1 Gas Service Pipes
The local gas region should be consulted at the
installation planning stage to either determine the
feasibility of providing a gas supply or, where there is
an existing supply, to ensure that the meter capacity
is adequate for the rated input of the proposed new
boiler. An existing gas service pipe must not be
used without prior consultation with the local gas
region.
5.2 Gas Meters
A new gas meter will be connected to the service pipe by
the local gas region, or a local gas region contractor. An
existing meter should be checked, preferably by the gas
region, to ensure that it is adequate to deal with the rate
of gas supply required.
5.3 Gas Supply Pipes
Supply pipes must be fitted in accordance with IM/16.
Pipework from the meter to the boiler must be of
adequate size. Do not use pipes of a smaller size than
the boiler gas connection. The complete installation
must be purged and tested for soundness as described
in IM/2 and IM/5 as appropriate.
A manual shut off valve must be fitted on the incoming
gas supply pipe, adjacent to each boiler, in an easily
accessible position.
5.4 Boosted Gas Supplies
Where it is necessary to employ a gas pressure booster,
the controls must include a low pressure cut-off switch at
the booster inlet. The local gas region must be consulted
before a gas pressure booster is fitted.
5.5 Boiler House Gas Control Valve
A manual valve for boiler house isolation shall be fitted in
the gas supply line. It shall be clearly identified and
readily accessible for operation, preferably by an exit.
5.6 Oil Supply
The oil storage & supply system should be designed
and installed in accordance with BS5410:Pt.2, as
appropriate.
The following notes are given as guidance :-
5.6.1 Oil Storage Tank
The oil storage tank should be of sufficient capacity
to permit economic deliveries of oil to be taken.
Reference should be made to oil distributor for
advice.
The tank should be installed such that:
a. The oil outlet should be higher than the top of the
oil burner pump. If site conditions prevent this, then
a suction lift (or 'two-pipe') fuel supply system must
be used.
b. The maximum head on the suction side of the oil
pump should not exceed 4 metres (14 feet).
c. The base should be sloped away from the outlet
and towards a drain cock to allow draining of any
water or sediment from the tank.
d. It is sited outside, if possible, and complies fully
with the requirements of the relevant British
Standards and Local Authority Regulations.
5.6.2 Oil Supply Lines
The oil supply line/s between storage tank and
burner should be run in copper, steel or aluminium
pipe. Galvanised pipes and fittings should not be
used. All pipework and fittings must be oil-tight, with
any screwed joints made good with an oil resistant
compound. The supply line should terminate
adjacent to the burner with an isolating valve and
metal bowl filter (with replaceable filter element). All
burners are supplied with flexible oil pipes to make
the final connection between the oil supply pipe and
the burner
5.6.3 Gravity Feed Supply
Where the delivery connection of the storage tank is
above the level of the pump inlet on the burner a
'single pipe' gravity feed system can be used. At no
point in this system should the supply pipework be
higher than the lowest level of fuel in the tank.
5.6.4 Suction Lift Supply
Where the delivery connection of the tank is below
the level of the pump inlet on the burner a 'two-pipe'
fuel supply system MUST be used. This system
uses the burner pump to provide a circulation of oil to
and from the tank.
NOTE:- Burner pumps can be supplied ready for use
on a 'single-pipe' system. For use on a 'two-pipe'
system it may be necessary to fit the pump with a
by-pass plug. Refer to technical information supplied
with burner.
The return line should terminate within the oil tank at
the same level as the suction line, in which case a
non-return valve is not required. If the return line
terminates above the fuel level, a non-return valve
MUST be fitted.
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6.0 FLUE SYSTEM
6.1 General Requirements
Detailed recommendations for flue systems are given in
BS 6644, & IGE UP/10. The following notes are intended
to give general guidance only.
The boiler should be connected to a single flue
system in the case of a single boiler, or a common
flue header in the case of a multiple boiler installation.
Flue systems must be self supporting, contain access
for cleaning and contain a maintenance joint near the
boiler outlet to allow for removal of the flue box
during servicing.
6.2 Design Waste Gas Volume and Temperature
It is recommended that the volume and temperature
of the waste gases used for design of the flue system
are as shown in Figure B.
6.3 Materials
Materials used for the flue system must be mechanically
robust, resistant to internal and external corrosion, non-
combustible and durable under the conditions to which
they are likely to be subjected.
Consideration should be given to possible freezing of
condense water traps and pipework. This must be
avoided at all times. Insulate condense pipes if freezing
temperatures are likely to be encountered.
Chimneys should be lined with a non-porous acid-
resistant material in accordance with BS 5854,
e.g. a flexible flue liner or similar British Gas
Approved material. The internal diameter of the liner
must not be less than the recommended flue size and
the number of joints should be kept to a minimum.
Any joint between the flexible liner and the flue pipe
from the boiler should be made using a purpose
made connector. Existing chimneys should be
thoroughly swept before use and any register plates,
dampers, or restrictions removed.
If the boiler/s is not connected to a chimney system,
but is connected directly to outside by a standard
stainless steel flue (either single or twin wall) it is
particularly important to ensure that the point at which
it exits the building is fully weatherproofed.
6.4 Suction
The flue system should be designed to maintain
atmospheric pressure or a slight suction at the boiler flue
connection at all times (0.1 - 0.3 mbar).
It is recommended that a draught stabiliser is fitted to the
flue system where the suction is likely to exceed 0.3
mbar.
6.5 Disconnection
Provisions should be made for disconnection of the flue
pipe for servicing. It is advisable that bends are fitted with
removable covers for inspection and cleaning as
appropriate.
NOTE:- The flue system must be self supporting and not
present a risk to people in or around the building.
See Section 13.0: Servicing for further information.
6.6 Flue Discharge
The flue system must ensure safe and efficient operation
of the boiler to which it is attached, protect the
combustion process from wind effects and disperse the
products of combustion to the external air.
The flue must terminate in a freely exposed position and
be situated so as to prevent the products of combustion
entering any opening in a building. Consideration should
be given to the fitting of a flue discharge terminal or grille
to stop the ingress of birds etc.
The flue system should be designed such that the
flue terminates at least 1 metre above the roof
surface, or above the level of any nearby structure
which is within 2.5 metres of the flue.
6.7 Surface Temperature
Combustible materials in the vicinity of the boiler and flue
shall not exceed 65 °C during boiler operation. The flue
shall not be closer than 50mm to any combustible
material, except where it passes through such material
with a non-combustible sleeve when the air gap may not
be less than 25mm.
6.8 Flue System Location
The flue system must not be placed or fitted where there
is undue risk of accidental damage to the flue pipe or
undue danger to persons in the vicinity.
NOTE:- The flue MUST be self supporting. Check that
the flue and chimney are clear from any obstruction.
6.9 Condensate Discharge
When designing the flue system, care must be taken
to ensure that any condensate which may form within
the system, can be safely drained to a suitable waste
point and, that the flue material used is resistant to
the corrosive effects of that condensate.
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7.0 AIR SUPPLY
Detailed recommendations for air supply are given in
BS 6644.
The following notes are intended to give general
guidance.
In all cases there must be provision for an adequate
supply of air for both combustion and general ventilation,
in addition to that required for any other appliance.
7.1 Air Supply by Natural Ventilation
The boiler room must have, or be provided with,
permanent air vents directly to the outside air, at high
level and low level.
For an exposed boiler house, air vents should be fitted
preferably on all four sides, but at least on two sides.
Air vents should have negligible resistance and must not
be sited in any position where they are likely to be easily
blocked or flooded or in any position adjacent to an
extraction system which is carrying flammable vapour.
Grilles or louvres must be so designed that high velocity
air streams do not occur within the space housing the
boiler.
The air supplied for boiler house ventilation shall be such
that the maximum temperatures within the boiler house
shall be as follows:
1) At floor level (or 100 mm above floor level) = 25 °C.
2) At mid-level (1.5 m above floor level) = 32 °C.
3) At ceiling level (or 100 mm below ceiling level) = 40°C
Where both low and high level openings are used, the
grilles shall have a total minimum free area of :-
Low Level (inlet) 540cm²plus 4.5cm²per kW
in excess of 60 kW total rated input (gross).
High Level (outlet) 270cm²plus 2.25cm²per kW
in excess of 60kW total rated input (gross).
7.2 Air Supply By Mechanical Ventilation
Air supplied to the boiler room by mechanical means
should be as follows :-
1) Mechanical inlet and mechanical extract can be utilised
providing design extraction rate does not exceed one
third of the design inlet rate.
2) Mechanical extract ventilation with natural inlet
ventilation MUST NOT be used.
NOTE:- For mechanical ventilation systems an automatic
control should be provided to cut off the gas supply to the
boiler, in the event of failure of air flow in either inlet or
extract fans.
Figure E - Mechanical ventilation Flow Rates
Flow Rate per 1000 kW
total rated heat input (gross)
Inlet air
(Combustion
Ventilation)
Extract air
(Ventilation)
m3/s m3/s
Volume 0.9 0.6
Forced Draught
Boilers
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HAMWORTHY HEATING LTD Page 500001113/D
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8.0 WATER CIRCULATION SYSTEM
8.1 General
Recommendations for the water circulation system
are given in BS 6644 and CP 342. The following
notes are of particular importance:-
1) In a combined central heating and hot water
system, the hot water storage vessel must be of the
indirect cylinder or calorifier type. The hot water
storage vessel should be insulated preferably with not
less than 75mm (3 in) thick mineral fibre, or its
thermal equivalent.
2) Circulating pipework not forming part of the useful
heating surface should be insulated to help prevent
heat loss and possible freezing, particularly where
pipes are run through roof spaces and ventilated
cavities. Cisterns situated in areas, which may be
exposed to freezing conditions, should also be
insulated. Insulation exposed to the weather should
be rendered waterproof.
3) Drain valves must be located in accessible
positions which permit the draining of the whole
system, including the boiler and hot water storage
vessel.
4) Each boiler has PN6 Flanged flow and return
connections located on the top/ rear section of the
boiler.
5) Multiple boilers should be connected by flow and
return headers. Headers should be connected to the
system in a "reverse return" arrangement (the water
flow in each header is in the same direction) to
ensure equal flow in each module.
Figure F - Cold Feed and Vent Pipe Sizes (mm)
8.2 Pressure Relief Valve (Safety Valve)
The most important single safety device fitted to a
boiler is its safety valve and each boiler, or in the
case of a modular installation, each bank of boilers,
must be fitted with a pressure relief valve to BS 759
or BS 6759 Pt.1 (ISO 4126) and sized as shown in
BS 6644.
BS 6644 provides comprehensive information for the
selection and location of safety valves and attention is
drawn to the higher capacity requirements of safety
valves for pressurised hot water systems.
8.3 Open Vent and Cold Feed Pipe
(See BS 6644 for further information.)
Every boiler or group of boilers should have an open
vent pipe and cold feed pipe installed between the
boiler and the first water isolating valve. The
minimum bore (mm) of these pipes per installation is
as follows:-
The vent pipe must rise continually, must not be
valved except by a design which when closed for
maintenance the boiler is open to atmosphere. The
pipe shall be protected against freezing where this
might occur.
8.4 Altitude Gauge (Water Pressure Gauge)
Every boiler or group of boilers should be provided
with a gauge complete with isolating valve. See
Figure A for typical position.
8.5 Thermometer
See Figure A for typical position.
A thermometer complete with pocket should be fitted
in the pipework to indicate water flow temperature.
8.6 Drain Valves
Each boiler should have ¾” NB drain valve fitted (not
H.H.L. supply), to drain the boiler only. A plugged Rc
¾” connection is provided for a drain valve at the
bottom of the front boiler section.
The heating system in total should have drain valves
as recommended by BS 6644. See Figure A for
recommended positions.
Boiler Output Feed Vent
60kW to 150kW 25 32
150kW to 300kW 32 38
300kW to 600kW 38 50
600kW & above 50 65
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8.7 Circulating Pump
One or more circulating pumps will be required to
circulate water around the boilers and heating
system. The pump should be sited to facilitate
servicing. It is also important that the existing system
be flushed through twice to remove any loose matter,
which may have accumulated. If in any doubt
regarding the cleanliness of the system, a coarse
filter should be fitted in the return pipework to the
boilers.
NOTE:- If boilers are run off time clock control, a
pump overrun (not H.H.L. supply) should be fitted
which must run for a minimum of 5 minutes on shut-
down of the last boiler.
8.8 Minimum Water Flow Rates
Minimum water flow rates are shown in Figure B.
These flow rates should be maintained through the
boiler at all times whilst the boiler is firing. If the
water flow rate is allowed to fall below the minimum,
the boiler heat exchanger could fail due to the
resultant scale formation. Particular attention should
be paid to the restriction of external flow circuits
during periods of low heat demand.
8.9 Waterside Pressure Drop
The waterside hydraulic resistance (Pressure drop) is
shown in Figure B.
8.10 Control Schemes
8.10.1 Temperature Controls
An adjustable control thermostat is supplied with each
boiler and should be set to operate within the range 65-
90°C for standard applications. A temperature limiter,
(hand reset limit thermostat) is also fitted to the boiler and
must be set at 100°C.
NOTE:- The minimum difference between control
thermostat and temperature limiter MUST NEVER be
less than 10°C.
Where the system is operating on a ∆T of 20°C, care
should be taken to ensure that the return temperature
does not fall below 50°C.
8.10.2 Water Flow Controls
Any external mixing valve/shunt pump or similar controls
should ALWAYS ENSURE that the minimum water flow
rate as shown in Figure B is maintained.
8.10.3 Frost Protection
Consideration should be given to fitting a frost thermostat
set at approximately 4°C.
8.11 Unvented Systems
See Figure A for typical layout of a Unvented
(Pressurised) Hot Water System.
For system design refer to BS 7074 Pt.2.
In order to correctly size a pressurisation unit for any
heating system certain parameters are required :-
1) Static height of highest component in system
(metres).
2) System volume - if it is not known a general rule of
thumb of 10 litres/kW of installed boiler power can be
used.
3) Maximum flow temperature (°C).
4) Maximum system hot working pressure, generally
given in bar g.
From the above information Hamworthy Heating can
size the pressurisation unit and also the expansion
vessel required. Care must be taken in sizing
expansion vessels to ensure maximum acceptance
factors are not exceeded. Normally manufacturers of
vessels impose a limit of 0.5. This value must not be
exceeded at any time during the operation of the
boiler: this includes the over pressure condition should
a safety valve lift.
Consideration should also be given to sizing of the
safety valve/s in the system.
See BS 6759:Pt.1, for information.
See also BS 6880:Pt.1,for design considerations.
8.12 Modular Boiler Control Schemes
For modular boiler installations, Hamworthy Heating
can supply a unique boiler management control
system called the ‘Marshall HE’. This system
comprises: a wall mounted master control unit, which
houses the main interface processor and will control
up to 8 stages. For further information, contact
Hamworthy Heating for details.
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9.0 ELECTRICAL SUPPLY
WARNING: THIS APPLIANCE MUST BE EARTHED
9.1 Site Wiring
Wiring external to the boiler must be installed in
accordance with the I.E.E Regulations and any local
regulations which apply. Wiring must be completed in
heat resistant cable. (For size, refer to the Technical
Instructions supplied by the burner manufacturer). The
boiler control panel requires a 230V, single phase 50 Hz
supply.
Fuse ratings for individual boilers are marked on the
appliance data plate. The control panel is supplied
with flying lead and plugs for direct connection to
corresponding sockets supplied with the burner.
Should non-standard connecting wiring be
necessary due to particular burners or contract
conditions, space is provided in Appendix A of these
instructions for a wiring diagram to be included.
Note a 3 phase 4 wire (including neutral) supply
is required from which the 3 phase should be
wired direct to the burner with a single phase
and neutral spurred off to the boiler control
panel.
The method of connection to the mains electricity supply
must facilitate complete electrical isolation of the single
boiler/battery with a contact separation of at least 3 mm
in all poles.
The appliance must be isolated from the mains
electricity supply in the event of electric arc welding
being carried out on any connecting pipework.
A mains isolator must be provided adjacent to the boiler
in a readily accessible position. The supply should only
serve the boiler.
NOTE:- Volt free contact electrical supplies must also be
isolatable where fitted (see note in control panel).
Further details regarding connection to the electricity
supply are given in BS EN 60335 Pt.1 or
BS 3456 Pt. 201.
9.2 Indication Signals and Volt Free Contacts
Control panels are fitted with v.f.c.’s (volt free contacts)
to enable external indicator lights or alarms to derive
signals for normal run, overheat and lockout.
NOTE:- These external circuits MUST be isolated
before any service or maintenance procedures are
carried out.
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14
H2 LB5B4N NN B4B5L1 E N T1T2S3B4B5T6T7T8
21
CC
12
C1 C2C3 C4 9 11 12 13 14 15 16 L N E
2
C
1
L1 E N T1 B4T2S3 T6B5 T8T7
13
2
HIGH / LOW THERMOSTAT
TEMPERATURE LIMITER
CONTROL THERMOSTAT
HIGH FIRE LOW FIRE
OVERHEAT
GREEN GREEN
RED
FUSE 6.3A MAX
POWER ON
(RED)
BLACK BLACK BLACK BLACK 2 8 7 H 1
1
13 12 11 5 4 3 2 H
BLACK BLACK
8 7
HIGH FIRE LOW FIRE
METER HOURS RUN METER HOURS RUN
BURNER
CONNECTIONS
8 7
8 7
PLUG MALE 4 PIN
PLUG MALE 7 PIN
L BLACK
9 14 6
GN/YE
COMMISSIONING / REMOTE LINKS
LOW HIGH
OVERHEAT
LOCKOUT
NORMAL RUN
SUPPLY IN
GN
/
YE
GN
/
YE
BOILER ON/OFF
VOLT FREE CONTACTS (if fitted)
LOCKOUT
230V ~ 50Hz through an isolator in accordance with Section 9.1
NOTE: THIS DIAGRAM SHOWS THE CONTROL PANEL WIRING 230V ~ 50Hz. SUPPLY. THE SUPPLY TO THE BURNER IS DEPENDANT UPON THE MODEL SELECTED; - REFER TO BURNER MANUFACTURERS INSTRUCTIONS.
Figure G - High / Low Burner Control Panel Wiring Diagram
Note: For modulating burner operation the 4 pin burner plug must be disconnected from terminals
B5, T6, T7 and T8 and discarded.

HAMWORTHY HEATING LTD Page 500001113/D
Wimborne GM
Item Description
6 7 8 9 10 11 12 13 14 15
2 Intermediate section 4 5 6 7 8 9 10 11 12 13
6 Guide ring 10 12 14 16 18 20 22 24 26 28
7 ‘O’ ring (7.3mm) 10 12 14 16 18 20 22 24 26 28
45 Boiler cement (packs) 5 5 6 7 8 9 10 10 11 11
46 Silicone sealant (tube) 9 11 12 13 15 16 18 19 20 21
47 Primer—silicone 2 2 2 3 3 3 3 3 4 4
56 Section tie bolts M12 x 230 20 24 28 32 36 40 44 48 52 56
73 Self tapping screw - casing 70 110 110 110 130 130 130 150 150 150
No. of sections
Figure H - Composition of heat exchanger
Figure I - Composition of heat exchanger assembly
15