Potterton Housewarmer 45 Installation and maintenance instructions

Potterton Housewarmer 45 - G.C. No. 44 590 18
Potterton Housewarmer 55 - G.C. No. 44 590 19
Installation & Service Instructions
Housewarmer 45 & 55
Gas Fired Electronic Back Boilers
BB45001B
THE GAS SAFETY (INSTALLATION AND USE) REGULATIONS 1994 (as amended).
‘‘ In your own interest, and that of safety, it is 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.’’
Installation must be in accordance with these installation & Service Instructions and the rules in force.
The polythene bags used for packaging are a potential hazard to babies and young children
and MUST BE DISPOSED OF IMMEDIATELY.
LEAVE THESE INSTRUCTIONS WITH THE USER FOR USE ON FUTURE CALLS
For Use With Natural Gas
(G20) Only At 20mbar
For Use in GB & IE
IMPORTANT
PLEASE READ THIS BOOK
BEFORE INSTALLING,
OPERATING OR SERVICING
THIS APPLIANCE.

Contents – Page 2
1. Technical Data.................................3
2. General.............................................4
3. Installation Requirements..............6
3.1 TheSystem .............................................6
3.2 Fireplace Opening & Hearth.................10
3.3 Chimneys & Flues ................................11
3.4 Electricity Supply..................................12
3.5 Gas Supply...........................................12
3.6 Air Supply & Ventilation........................12
4. Installation.....................................12
4.1 Pre-Installation Checks.........................12
4.2 Install the Boiler....................................12
4.3 Electrical Connections..........................16
5. Commissioning............................ 18
5.1 Commission the Boiler..........................18
5.2 Final Adjustments.................................18
5.3 Final Checks.........................................19
5.4 Re-check Flue Efficiency......................19
5.5 Install the Fire Front..............................19
5.6 Instruct the User...................................19
6. Servicing & Replacement Of Parts... 20
6.1 Preparation................................................20
6.2 Burner/Gas Valve Assembly......................20
6.3 Main Burner Injector..................................20
6.4 Lint Guard..................................................21
6.5 OxyPilot/Electrode Assembly.....................21
6.6 Burner........................................................21
6.7 Gas Valve..................................................22
6.8 Overheat Thermostat.................................22
6.9 Control Thermostat....................................22
6.10 Electronic Control Box...............................22
6.11 User Control Box .......................................22
6.12 Heat Exchanger.........................................22
7. Fault Finding...................................... 24
8. Electrical Diagrams ........................... 25
9. Flow Diagrams................................... 26
10. Short List Of Spares.......................... 27
Gas Fires
The Potterton Housewarmer 45 & 55 Back Boiler Units can be fitted with a variety of approved Potterton
Housewarmer Gas Fires. The range comprises of Radiant, Live Fuel Effect and Inset Decorative Models.
Accessories
The following Potterton Myson controls are recommended for use with your boiler:-
Electronic Programmer EP2002, EP3002 or EP6002
Cylinder Thermostat PTT2 or PTT100
Room Thermostat PRT2 or PRT100
Frost Thermostat PRT100 FR
Motorised Zone Valve MSV222 or MSV228
Motorised Diverter Valve MSV322
Thermostatic Radiator Valve
Data sheets describing these products are available on request.

1. Technical Data – Page 3
Potterton Potterton
Housewarmer 45 Housewarmer 55
Heat Input 16.8kW (57,300Btu/h) 20.4kW (69,620Btu/h)
Heat Output 13.2kW (45,000Btu/h) 16.1kW (55,000Btu/h)
Gas Rate 1.6m³/h (56.5ft³/h) 1.95m³/h (68.78ft³/h)
Inlet Pressure 20mbar 20mbar
Burner Pressure 13.4mbar (5.36in wg) 15.5mbar (6.20in wg)
Classifications I2H & B11 AS I2H & B11 AS
Burner Aeromatic 7 Blade Aeromatic 8 Blade
Burner Injector Multihole 1 off - 7 x 1.25mm Multihole 1 off - 6 x 1.45mm
Pilot Burner SIT OxyPilot SIT OxyPilot
Spark Gap 3 to 6mm 3 to 6mm
Ignition Intermittent Pilot Intermittent Pilot
Electrical Supply 230-240v ~ 50HZ 230-240v ~ 50HZ
Fuse Rating - External 3A 3A
Packed Weight 41kg (90.5lbs) 41kg (90.5lbs)
Water Capacity 4 litres (0.9 gal) 4 litres (0.9 gal)
Gas Supply Connection 15mm Compression 15mm Compression
Flow Connection Rc1 Rc1
Return Connection Rc1 Rc1
Injector Tee 28/22mm 28/22mm
Maximum Flow Temperature 82°C 82°C
Design Temperature Rise 11°C 11°C
Maximum Static Head 30.5m (100ft) 30.5m (100ft)
Minimum Static Head 0.9m (3ft) 0.9m (3ft)
Head Loss at 11°C Temp. Rise:-
without Injector Tee 0.05m (1.9in) 0.06m (2.7in)
with Injector Tee 0.28m (11.0in) 0.40m (16.0in)
Recommended Flow through Boiler 17.3 litres/min (3.8 gals/min) 20.9 litres/min (4.6 gals/min)
Flue Size 125mm (5in) 125mm (5in)

2. General – Page 4
Please read these Installation & Service Instructions and the
one supplied with the Gas Fire before installing the boiler.
This Potterton boiler is part of a combined back boiler and
gas fire unit, which should be fitted in a fireplace or standard
builder's opening, at the base of a chimney.
This appliance is for use on Natural Gas (G20) only and
MUST NOT be used on any other gas.
The combined appliance will be delivered in 2 or 3 packages
depending on the chosen gas fire. One pack contains the
boiler, the other contains the gas fire. If the fire chosen is an
inset decorative then the facia will be the third pack.
Samples of the Potterton Housewarmer back boiler have
been examined by British Gas Plc, a United Kingdom
Notified Body, and the range is certified to comply with the
essential requirements of the G.A.D. and is permitted to
carry the CE Mark.
The installation must be in accordance with the following:-
Local Building Regulations
Latest edition of I.E.E. Regulations
By-Laws of the Local Water Undertaking and the Current
Edition of the following standards:-
BS 5440:1 Flues (for gas appliances of rated input not
exceeding 60kW)
BS 5440:2 Air Supply (for gas appliances of rated input
not exceeding 60kW)
BS 5449:1 Forced Circulation Hot Water Systems
BS 5546 Installation of Gas Hot Water Supplies for
Domestic Purposes
BS 5871 Installation of Gas Fires, Convectors and
Fire/Backboilers
BS 6400 Specifications for Installation of Domestic
Gas Meters (2nd family gases)
BS 6644 Boilers of Rated Input not exceeding 60kW
BS 6798 Specification for Installation of Gas fired Hot
Water Boilers
BS 6891 Low Pressure Installation Pipes
British Gas Specifications for Wet Domestic Central Heating
Systems.
524
241
Gas
Fire
Wall
Face
213
176
352
358
148
400
333
355
550
30
127
30
248
BB45002B
122
145
Fig. 1

2. General – Page 5
fig 2
IMPORTANT
This appliance has been certified for safety. It is therefore important that no external control device (e.g. flue dampers,
economisers, etc.) be directly connected to the appliance unless covered by these Installation & Service Instructions or
otherwise recommended in writing.
Any direct connection of a control device not approved by Potterton Myson Ltd, could invalidate the
CE Certification and normal appliance warranty.

3. Installation Requirements – Page 6
3.1 The System
The boiler must be used on INDIRECT hot water systems
only. It is suitable for use on open vented gravity domestic
hot water/pumped central heating systems or, fully pumped
systems which may be sealed or open vented.
The system should be designed so that the maximum static
head does not exceed 30.5m (100ft) and a minimum on fully
pumped systems of 0.9m (3ft). See Fig. 5.
Gravity domestic hot water circuits should have a minimum
circulating head of 1.2m (4ft). See Fig. 4.
To prevent reverse circulation in the gravity circuit when the
pump is running an injector tee is provided - See Fig.14. The
orientation of the tee is not important.
The pump should preferably be fitted in the flow, though
installation in the return is acceptable providing care is taken
to ensure air is not drawn into the system due to the
negative pressure effects of the pump. Isolating valves must
be fitted as close as possible to allow replacement without
system draining.
Drain off taps should be fitted in the pipework close to the
boiler and in the low points of the system.
Combined Gravity Hot Water Pumped Central Heating
Systems.
Where a cylinder thermostat and zone valve is used to
control the temperature of the hot water it is recommended
that a by-pass be installed in the gravity circuit. A suggested
method of doing this is shown in Fig. 4. where the bathroom
radiator is connected into the gravity circuit and is fitted with
two lockshield valves. Mechanically operated thermostatic
domestic hot water temperature control valves which allow
the boiler to operate when the valve is closed or partially
closed MUST NOT BE FITTED.
Note: Flow connections can be fitted to either upper
tappings, return connections to either of the lower tappings.
When not using the Injector Tee, the flow and return
connections must be fitted on the same side.
Fully Pumped Systems
We recommend that if possible the pump be wired directly to
the terminal block (See Fig. 17) as it will allow the pump to
be controlled by the over-run device. This will ensure that the
pump will continue to run after boiler shut down thus
preventing nuisance operation of the overheat thermostat.
If the pump is not wired directly to the terminal block, then a
by-pass circuit is not necessary.
If a three port diverter valve is used as shown in Figs.5 & 6,
a by-pass is not necessary since one circuit is always open.
Where a pair of two port valves are used, a by-pass is
necessary. It should be fitted with a lockshield valve and be
adjusted to maintain a minimum flow through the boiler of
4.5 litres/min (1 gal/min) see Figs. 5 & 6.
Systems fitted with controls which allow the boiler to operate
when both the hot water and central heating circuits are
closed i.e. mechanically operated thermostatic control
valves, must be fitted with a by-pass circuit capable of:-
1. Dissipating a minimum of 1kW (3,400 Btu/h)
2. Maintaining a minimum water flow through the boiler
of 9 litres/min (2 gal/min).
A suggested method of meeting these requirements by using
a bathroom radiator fitted with two lockshield valves is
shown in Figs. 5 & 6.
Diagrammatic layouts of a fully pumped system and a
combined pumped central heating/gravity hot water system
are shown in Figs. 4 & 5.
Sealed Systems (Fully Pumped)
Installation
The installation must comply with the requirements of BS
6798; 1987 and BS5449: Pt 1. The British Gas publication
"British Gas Specification for Domestic Wet Central Heating
Systems" should also be consulted.
Safety Valve
A non-adjustable spring-loaded safety valve, preset to
operate at 3 bar (45lbf/in²) shall be used. It must comply with
BS 6759: Pt 1. and include a manual testing device. It shall
be positioned in the flow pipe either horizontally or vertically
upwards and close to the boiler. No shut-off valves are to be
placed between the boiler and the safety valve. The valve
should be installed into a discharge pipe which permits the
safe discharge of steam and hot water such that no hazard
to persons or damage to electrical components is caused.
Pressure Gauge
A pressure gauge incorporating a fill pressure indicator,
covering the range 0 - 4 bar (60 lbf/in²) shall be fitted to the
system. It should be connected to the system, preferably at
the same point as the expansion vessel. Its location should
be visible from the filling point.
Expansion Vessel
A diaphragm type expansion vessel to BS4814: Pt 1. shall
be fitted close to the inlet side of the pump. The connecting
pipework should not be less than 15mm. Pipework
connecting the expansion vessel should not incorporate
valves of any sort. Methods of supporting the vessel are
supplied by the vessel manufacturer. The nitrogen or air
charge pressure of the expansion vessel shall not be less
than the hydrostatic head, (height of the top point of the
system above the expansion vessel).

3. Installation Requirements – Page 7
To size the expansion vessel it is first necessary to calculate
the volume of water in the system in litres. The following
volumes may be used as a conservative guide to calculating
the system volume.
Boiler Heat Exchanger: 4litres
Small Bore Pipework: 1 litre per kW of system
output
Micro Bore Pipework: 7 litres
Steel Panel Radiators: 8 litres per kW of system
output
Low Water Capacity Radiators: 2 litres per kW of system
output
Hot Water Cylinder: 2 litres
If the system is extended, the expansion vessel volume may
have to be increased unless provision has been made for
extension. Where a vessel of the calculated size is not
available, the next available larger size should be used.
The boiler flow temperature is controlled at approximately
82°C.
The vessel size can now be determined from the information
in Table 1 where V = System volume in litres.
Cylinder
The hot water cylinder must be an indirect coil type or a
direct cylinder fitted with an immersion calorifier suitable for
operating at a gauge pressure of 0.3 bar (5 lbf/in2) in excess
of safety valve setting. Single feed indirect cylinders are not
suitable for sealed systems.
Method of Make-up
Provision shall be made for replacing water loss from the
system either:
i) from a make-up vessel or tank mounted in a position
higher than the top point of the system, and connected
through a non-return valve to the system on the return
side of the hot water cylinder or the return side of all
heat emitters. or
ii) where access to a make-up vessel would be difficult by
using the mains top up method or a remote automatic
pressurisation and make-up unit as shown in
Figs. 7 & 8.
Mains Connection
There shall be no connection to the mains water supply or to
the water storage tank which supplies domestic hot water
even though a non-return valve, without the approval of the
Local Water Authority.
Vessel Charge Pressure (bar) 0.5 1.5 Filling Point
Initial System Pressure (bar) 1.0 1.0 The system shall be fitted with a filling point at low level
Expansion Vessel Volume (litres) V x 0.11 V x 0.087 which incorporates a stop valve to BS 1010 and a double
Table 1. check valve (approved by the National Water Council) to be fitted in this order from the system mains, see Fig. 7.
FlowFlow
ReturnReturn
Central
HeatingCentral
Heating
Injector
Tee
Injector
Tee
1.2
Metres
Min.
30.5
Metres
Max.
Water Level
Heat
ExchangerHeat
Exchanger
Flow
Return
Central
Heating
Flow
Return
Central
Heating
Heat
Exchanger
30.5M Max.
0.9M Min.
Water Level
Flow
Fully
Pumped
System
Return
Heat
Exchanger
Heat
Exchanger
BBU Open Vented
System Variants
All Systems Illustrated
Can Be Fitted To The
Other Side Of the Boiler
On Combined Gravity
D.H.W. Pumped Heating
Systems The Injector
Tee Is To Be Fitted
Directly To The Boiler.
The Tee On The
Combined Flows Is
To Be Fitted As Close
To The Boiler As Possible
BB45004C
Injector Tee
can be installed
in any direction
see Fig 14
Fig 3

3. Installation Requirements – Page 8
Flow
Return
Injector
Tee
Min
Circulating
Head 1.2m
(4ft)
Optional
Zone
Valve
By-pass Using Bathroom
Radiator Connection Into
Gravity Circuit & Fitted
With Two Lockshield
Valves To Be Installed
When A Zone Valve Is
Fitted In Gravity Circuit
Open Vented Gravity Domestic
Hot Water & Pumped Central
Heating System
BB45005C
An Anti Gravity Check Valve,
Or Some Other Mechanical
Device (E.G. Motorised Valve,
Gate Valve), Should Be Fitted
To The Radiator Circuit Where
It Is Required To Prevent
Gravity Circulation When
The Pump Is Not Operating.
Fig. 4
Flow
Return
Max. 30.5m (100ft)
Min. 0.9m (3ft)
Top Of
Heat
Exchanger
Alternative By-pass
arrangement Using
The Bathroom
Radiator Fitted With
Two Lockshield Valves
Open Vented
Fully Pumped
System
Fitted With
A Combined
Feed & Vent
Water Level
Optional
Zone
Valves
Optional
3 Port
Valve
BB45006B
Vent
By-pass
Balancing
Valve
If The Pump Is Not Wired Directly To The Terminal Block,
Then A By-Pass Is Not Necessary
Fig. 5

3. Installation Requirements – Page 9
Flow
Return
Alternative By-pass
arrangement Using
The Bathroom
Radiator Fitted With
Two Lockshield Valves
Fully Pumped
Sealed System
Optional
Zone
Valves
Optional
3 Port
Valve
Vent
Make Up
Vessel
By-pass
Balancing
Valve
Filling
Point
Pressure
Gauge
Safety
Valve
Expansion
Vessel
BB45007A
Fig. 6
Double
Check
Valve
Stop
Valve
Mains Water
Supply
(Service Pipe)
Temporary
Hose
Filling A Sealed Water System
(Method 1)
Note: This Method Of Filling A
Sealed System May Only Be
Used If Acceptable To local
Water Undertaking
Mains Topping-Up Method
Heating
System
Hose
Union
BB45008A
Fig. 7
Overflow
Mains
Water
Supply
Cistern
Stop
Valve
Filling A Sealed Water System
(Method 2)
Note: Cistern To Be Supplied
Through A Tempory Connection
From A Service Pipe Or
Cold Water Distributing Pipe
Cistern Filling Method
Heating
System
Pressure Pump
Reducing Valve
(If Required)
BB45009A
Fig. 8

3. Installation Requirements – Page 10
3.2 Fireplace Opening & Hearth
For all installations the boiler requires a standard builder's
brickwork opening (fireplace recess) irrespective of the fire
model fitted. The builders opening must measure a minimum
of 406mm wide x 560mm high x 362mm deep having a front
opening (which may be a fire surround) to the same
minimum width and height dimensions. The base of the
opening and the top of the hearth must be flat and level.
Allowance for the pipework in the opening should be taken
into account before installation.
For the maximum width and height dimensions refer to the
Installation & Service Instructions supplied with the fire.
If the surround depth is too deep care must be taken to
ensure that the flue connection can be made. See Fig. 1 for
relevant dimensions.
The flat surface area and hearth requirements are shown in
the Installation & Service Instructions supplied with the fire.
Note: If the fireplace opening is to be newly constructed, it
is advisable to use the maximum dimensions shown in the
gas fire Installation & service Instructions.
On certain installations it may be convenient to run the gas
or electricity supply through from the inside of the fireplace.
Using the dimensions given in Fig. 1., ascertain the best
position for the pipework to enter the fireplace and make the
appropriate openings.
350mm
300mm
350mm
Illusion/Stratton/Presence/
Illusion 2/Presence 2/Firestar/
Knightsbridge
Allure/Brava/
Brava 2/Charm/Decor
Mainflame/Legend/
Harmony/Pageant
Gas Fire Name Min. Dimension
650mm
700mm
700mm
Illusion/Stratton/Presence/
Illusion 2/Presence 2/Firestar/
Knightsbridge
Allure/Brava/
Brava 2/Charm/Decor
Mainflame/Legend/
Harmony/Pageant
Gas Fire Name Min. Dimension
BB45010d
406
362
560
All Dimensions Quoted In This Diagram
Are In mm And Are Of Minimum Dimension
Non
Combustible
Material
(Min. 12mm)
50
Min
Floor
Level
Fig. 9

3. Installation Requirements – Page 11
3.3 Chimneys & Flues
1) A flue system (lined throughout its
length) must be provided to evacuate the
flue products of combustion from the
boiler. Reference should be made to the
building regulations and BS 5440:1. and
the flue system efficiency should be
checked in accordance with BS5440.
2) Ideally a flue should rise vertically and
any terminal or termination point shall be
positioned so that combustion products
can disperse safely at all times.
Therefore for practical purposes, the flue
should have the shortest possible run to
external atmosphere, with as near
vertical rise as possible, 90° bends
should be avoided. The terminal must be
at least above roof level and of a type
approved by British Gas.
3) There must be at least 2.5m equivalent
of vertical flue from the boiler flue socket.
4) Horizontal runs should be avoided,
however if a near horizontal flue run is
unavoidable, the total vertical height
necessary should be calculated in
accordance with BS 5440:1.
5) If an existing chimney is used, ensure
that it is thoroughly swept before lining or
connecting the boiler. The liner must
have an internal diameter of 125mm and
be acceptable by British Gas.
6) Care should be taken to avoid
condensation in the flue.
7) Where a flue liner is necessary (use a
non-porous acid resistant type) slide the
liner into the chimney to finish at a height
of 547mm above the hearth level on
which the boiler will stand. Fit an
approved outlet terminal to the top of the
liner, seal and clamp as shown. A
sealing plate should also be fitted and
sealed to close off the base of the
chimney.
8) In the case of a pre-lined chimney, it
must be connected to the socket of the
boiler flue hood with a length of liner.
9) Where a chimney lined with a vitreous
enamelled flue liner is used, connect and
seal a short length of flexible liner into
the base of the flue, to finish at the
correct height above the hearth level.
10) A precast concrete flue block system
may be used provided the cross
sectional area is at least 129cm sq. and
the precautions outlined in BS 5440:1
are observed.
Seal
Seal
Liner
Approved
Terminal
Cement
SealSealing
Plate
Set Into
Chimney
362
Seal
Seal
Pre-lined
FlueLiner
362
BB45011A
Fig. 10

3. Installation Requirements – Page 12
3.4 Electricity Supply
A 230-240v ~ 50 Hz, single phase electricity supply fused to
3A, must be provided in accordance with the latest edition of
the I.E.E. Wiring Regulations and any other local regulations
which may apply.
The current rating of the wiring to the boiler must be at least
3A in accordance with BS6500, Table 16, and have a cross-
sectional area of at least 0.75mm sq. (24/0.20mm). Heat
resistant cable should be used to wire the boiler.
The method of connection to the mains electricity supply
must facilitate complete isolation of the boiler together with
any external controls fitted in the system preferably by the
use of a fused 'three pin' plug and shuttered socket outlet;
both complying with the requirements of BS1363.
Alternatively, a fused double pole switch, having a 3mm
contact separation in both poles and serving only the boiler
and external controls may be used.
3.5 Gas Supply
The gas meter and supply pipe should be checked to ensure
that they are adequate for the boiler and any other appliance
already fitted; your Local Gas Region will assist in this
matter.
The recommendations of BS 6891 & BS 6400 must be
observed. Any part of the gas supply pipe running within the
chimney recess, should be suitably protected, (e.g. coated or
wrapped with PVC tape).
3.6 Air Supply & Ventilation
The ventilation of the room containing the boiler shall include
air for combustion and draught diverter dilution.
A permanent air vent must be fitted either directly to the
outside of the building or into a room or space containing a
permanent air vent of the same effective area. The air vent
must not enter the room through the builders opening.
The minimum effective area of the air vent required is as
follows:- 45 Back Boiler and Gas Fire: 73cm²
55 Back Boiler and Gas Fire: 89cm²
Any air grille and/or duct should be so sited and of a type not
to become easily blocked or flooded and should offer low
resistance to air flow.
If an extraction fan is fitted in any position which could affect
the air supply to the boiler, then a spillage test with the fan
running as detailed in BS5440:1 must be carried out.
4. Installation – Page 12
4.1 Pre-Installation Checks
Before installing the boiler check that:-
1) All register or restrictor plates and dampers from the flue system have been removed.
2) That the chimney has been swept.
3) That all rubble has been removed from the fireplace opening.
4) That if one is to be used the fire surround and hearth have been fitted and sealed to the wall.
5) That the base of the opening is horizontal and level.
6) That all necessary openings have been made in the fireplace for pipework and gas or electricity supplies.
7) That the flue has been lined (if required).
4.2 Install the Boiler
Important
If the gas supply is to come in on the left hand side, read
paragraph 7 now.
1) Make the required fittings to the boiler.
2) Undo the two wing nuts and remove the combustion
chamber front cover.
3) Remove the burner/gas valve assembly - 1 screw and
put safely to one side.

4. Installation – Page 13
4) Locate the boiler in the fireplace opening ensuring that
the 'V' in the front plate is about the centreline of the
opening and horizontally aligned with the front
opening.
5) Offer the spigot hood up to the flue hood to ensure it
will fit inside the front opening.
6) Mark the position of the fixing holes, move the boiler
clear of the marked points then drill and plug the
holes.
7) Position the boiler back over the holes and secure to
the floor with the 2 No. 8 x 1" Pozi Woodscrews
provided.
8) Run the gas supply preferably from the right hand side
of the opening. If the gas supply comes in from the left
it must cross to the right, behind the boiler if possible.
If crossing the front of the boiler, ensure that it will not
obstruct removal of the burner tray (when
Centre
Line
Before Securing
The Boiler Check
To See If It Is
Central By
Placing The
Flue Hood
Extension
In Position
Line The Boiler
Up With The
Front Of The
Fire Place
Opening
Fixing
Holes
BB45013A
Fig. 12
fitted).The gas
supply pipe in the opening should be protected by
wrapping in PVC tape.
Note: The flue hood can be removed (4 nuts) to improve
access when connecting the system pipework. Ensure
the rope seal is correctly aligned on re-assembly.
Remember ! The burner/gas valve assembly will be fitted
later, ensure the system pipework will not pass through this
area.
9) Connect the system pipework to the boiler. A drain
off tap should be installed close to the boiler if it is
in a low point of the system.
Note: On combined Gravity DHW Pumped Heating
Systems the injector tee must be fitted directly to
the boiler. The tee on the combined flows is to be
fitted as close to the boiler as possible.
10) Effectively seal all openings around the system
pipework
Fit Flow
Connection
Fit Return
Connection
Draft
Diverter
Flue
Liner
Flue Liner
Securing
Screw
BB45014A
Fig. 13
11) Connect the flue liner to the socket on the flue hood
using the 2 screws fitted to the socket. Seal the
joint with a suitable material.
12) Remove the top two screws from the draft diverter,
locate the flue hood extension and secure using the
screws removed.
Injector Tee
28mm (O/D)
D.H.W.
Gravity Return
28mm
BB45015C
22mm (O/D)
C.H. Return
Can be
installed
in any
direction
Fig. 14

4. Installation – Page 14
Main Burner
(45 Model)
Burner
Securing
ScrewGas
Valve
Combustion
Chamber
Gas Fire
Supply
Pipe
OpenClosed
BB45016B
Boiler
Gas
Service
Cock
Fig. 15
13) Loosely fit the gas service cock to the gas valve.
14) Re-fit the burner/gas valve assembly and secure with
the screw previously removed.
15) Re-fit the combustion chamber front cover and secure
using the wing nuts previously removed.
16) Connect the mains gas supply to the gas service cock.
17) Connect the gas fire supply pipe to the gas valve. This
is supplied with the fire.
18) Fully tighten all gas joints.
Refer to Fig. 16.
19) Attach the gas fire mounting bracket to the boiler using
the wing nuts supplied on the boiler. The bracket is
supplied with the fire.
20) Insert the gas fire isolation tap through the hexagonal
opening in the gas fire mounting bracket and
Main Burner
(55 Model)
Burner
Securing
ScrewGas
Valve
Combustion
Chamber
Gas Fire
Supply
Pipe
OpenClosed
Boiler
Gas
Service
Cock
BB45033B
Fig. 15A
secure using the locknut. Connect the gas fire supply
pipe to the isolation tap. The gas fire isolation tap
complete with locknut is supplied with the boiler.
Important
Ensure the isolation points on both the boiler gas
servicecock and the gas fire isolation tap are in the OFF
position.
21) Secure the electronic control box to the gas fire
mounting bracket using the screws provided.
22) Secure the user controls to the gas fire mounting
bracket using the screws provided.
23) Push the coiled overheat stat sensor into the right
hand socket. Secure using the plastic screw. If the
boiler is to be used on a Gravity DHW system the
overheat sensor must be repositioned as shown.
24) Connect the electrics as shown in section 4.3.
.Important:
Do not switch on the electric supply

4. Installation – Page 15
Insert
Screws
Into User
Control
User
Control
For Illusion, Illusion 2, Straton, Presence Presence 2, Firestar & Knightsbridge -
See The Installation & Service Instructions Supplied With The Fire
Illusion Bracket
Fig. 16

4. Installation – Page 16
4.3 Electrical Connections
The boiler and all external control circuit wiring must be
supplied from the same single isolating switch or plug and
socket, and should be fused at 3A.
Care must be taken to ensure that all wiring to the boiler will
not contact any sharp edges or hot surfaces.
We recommend that the supply be routed within the opening
and clipped to the side of the recess.
Use Fig. 17. as a reference for connecting the following
components:-
1) Connect the user controls plug onto its socket on the
electronic control box and secure the harness using the
cable clips.
2) Connect the electrode lead plug onto its socket on the
electronic control box.
3) Connect the gas valve plug onto its socket on the
electronic control box and secure the harness using the
cable clips.
4) Connect the control stat plug onto its socket on the
electronic control box.
5) Route a 4 core cable under the cable clamp and
connect to the 6 way terminal block as follows:-
Systems Using Pump Overrun Facility
Re-position link LK1 on the electronic control box so the link
wires are to the top of the board (Gravity Link Broken).
Permanent live to terminal marked MAINS 'L'.
Neutral to terminal marked MAINS 'N'.
Earth to terminal marked ' '.
Switched live from external controls to terminal marked
MAINS 'SwL'.
Following the pump manufacturers instructions, connect the
pump supply wires to the terminals marked 'Pump' L, N &’
‘on the terminal block and secure using the cable clamp.
Note: Ensure that the earth connector is longer than the L, N
& SwL from the point of anchorage, so that the current
carrying conductors become taut before the earth conductor.
Systems NOT Using Pump Overrun Facility
Switched live from external controls to terminal marked
MAINS 'SwL'.
Neutral to terminal marked MAINS 'N'.
Earth to terminal marked ' '.
The link LK1 should be left with the link wires to the bottom
of the board (Gravity Link Connected).

4. Installation – Page 17

5. Commissioning – Page 18
5.1 Commission the Boiler 9) With the main burner running, check for gas
soundness around the boiler using leak detection fluid.
Important
The commissioning and boiler adjustment must only
be carried out by a suitably qualified personnel.
Potterton Myson offer this service on a chargeable basis.
10) Allow the system to reach maximum working
temperature and examine for leaks. Set the boiler
switch to 'Off' and drain the system whilst still hot.
Important
When checking for gas soundness open
all windows and doors in the room.
Extinguish all naked lights, cigarettes, pipes, etc.
Note: Should the boiler fail to operate correctly refer to the
Fault Finding Guide on Page 24, and the
boiler wiring diagram on Page 25 for further information.
Open Vented Systems - Remove the pump and flush the
system thoroughly with cold water. Re-fit the pump. Fill and
vent the system then check for leaks.
Sealed Systems - Note: The system can be filled using a
sealed system filler pump with a break tank or by any other
method approved by the Local Water Authority. Refer to
Section 3.1, 'The System' on Page 6 of these instructions.
Remove the pump and flush the system thoroughly with cold
water. Re-fit the pump. Fill and vent the system until the
pressure gauge registers 1.5 bar (21.5 lbf/in²) and check for
leaks. Raise the pressure until the safety valve lifts, this
should occur within ± 0.3 bar of the preset lift pressure of 3
bar. Release water to attain the correct cold fill pressure.
All Systems
1) The whole of the gas installation must be checked for
soundness and purged in accordance with BS 6891.
2) Set the timer switch on the electronic control box to
position '0'
3) Set the boiler switch on the user controls to 'Off'
4) Turn the boiler gas service cock to the 'On' position and
then turn On the main gas supply.
5) Ensure the system is full of water and that the pump
and radiator isolating valves are open.
6) Switch On the main electricity supply at the isolating
switch or plug and socket.
7) Ensure that the time control, if fitted, is in an ON
condition and that the room and cylinder. thermostat,
where fitted are set to high temperatures
11) Re-fill and vent the system making a final check for
leaks.
On sealed systems adjust to the correct cold fill pressure.
Set the pressure gauge pointer to the system design
pressure.
If a by-pass circuit is fitted the by-pass valve should be
adjusted with the boiler operating under minimum load
conditions to maintain sufficient water flow through the boiler
to ensure that the overheat thermostat does not operate
under normal conditions.
Preliminary electrical system checks must be carried out.
They are:- Earth Continuity, Short Circuit, Polarity &
Resistance to Earth.
5.2 Final Adjustments
1) Remove the screw and fit a pressure gauge to the
burner pressure test point on the burner feed pipe.
2) Turn the boiler on and allow to run for 10 minutes.
3) Check that the burner pressure is in accordance with
the information on the boiler data badge.
4) If burner pressure adjustment is required, remove the
cap on the side of the gas valve and turn the screw
underneath - clockwise to increase pressure.
5) Check at the Gas Meter that the heat input is correct.
6) Shut down the boiler, remove the pressure gauge, re-
fit the screw and check for gas soundness. Re-fit the
cap (snaps on) onto the side of the gas valve.
7) Set the timer switch to suit system reqirements. See
5.3, Timer Switch.
8) Set the slider control on the user controls to 'Hi' and the
boiler switch to 'On'.
First time lighting: The pilot will attempt to light, if the pilot
does not light within 60 seconds (due to air in the system)
the boiler controls will go to 'Lockout' and the LED on the
user controls will go Red. To re-start the lighting sequence
press the reset button on the user controls. There will be a
short delay before the lighting sequence starts.
When the pilot flame has established and the burner lights
the LED on the user controls will go Green.
Combustion
Chamber
Burner
Securing
Bracket
Main Burner
(45 Model)
Burner
Securing
Screw
Gas
Valve
Pressure
Test
Screw
BB45019B
Gas Pressure
Adjusting
Screw
Remove
Cap
Fig. 18

5. Commissioning – Page 19
5.3 Final Checks
OxyPilot Burner
The pilot is pre-set and no adjustment is required. When lit
the pilot flame envelope should just cover the electrode tip
and spark earthing post.
If the pilot flame is not as described, replace the OxyPilot as
covered in Section 6 - Servicing & Replacement of Parts.
Timer Switch
This switch is internally connected to the gas control valve
circuit and a timed pump over-run circuit.
At switch position '3' the main burner will remain off for
approximately 3 minutes following operation of the control
thermostat thereby preventing rapid cycling. Also, on fully
pumped systems where the pump is wired to the boiler
control board, the pump will operate for approximately 3
minutes following shut down of any system controls.
BB45035A
Pilot
Flames
Fig. 19
Switch position '1' provides timings of approximately 1
minute.
Switch position '0' eliminates timing delay and should only be
used during commissioning.
It is suggested that switch position '3' is used wherever
possible. However, if the time delay adversely affects hot
water recovery times on gravity systems, position '1' should
be used.
Other Boiler Controls
No further setting or checking is necessary as all boiler
mounted controls are designed so that if a fault should occur
they will fail safe.
External Controls
Check that any other external controls connected in the
system, such as clocks or thermostats, control the boiler as
required.
5.4 Re-check Flue Efficiency
Before installing the fire front perform the following:-
Control Thermostat
At its minimum and maximum settings, the thermostat
should control the water flow temperature at approximately
57°C - 82°C.
Set the boiler switch to 'Off' and check that the main burner
shuts down.
Overheat Thermostat
The overheat thermostat is pre-set and no adjustment is
possible. It will require manual re-setting if an overheat
condition occurs (the LED will go Red).
The re-set button is located at the bottom right of the user
control box.
Re-check the flue system efficiency in accordance with BS
5440 whilst the boiler is operating.
5.5 Install the Fire Front
Install the gas fire and check for spillage as detailed in the
Installation & Service Instructions supplied with the gas fire.
5.6 Instruct the User
On completion of the installation, the installer should
demonstrate the operation of the boiler and its associated
controls. Also hand over all the instructions.

6. Servicing & Replacement of Parts – page 20
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BB45021B
ON
OFF
3
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2
2
1
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Fig. 20
WARNING:
Before commencing work turn the fire off, turn the boiler
switch to 'OFF'' and Isolate the electricity supply to the boiler.
Allow the fire and boiler to cool.
IMPORTANT:
Always test for gas soundness after completing any
replacement of gas carrying components and carry out
functional checks of controls.
In the interests of hygiene, please wash your hands after
working on this appliance.
Re-assemble in reverse order unless otherwise stated.
If cleaning the heat exchanger at any time, proceed as
follows:-
Perform sections 6.1 and 6.2. Remove the spigot hood and
down draught diverter - 2 screws The heat exchanger. can
Main Burner
(45 Model)
Burner
Securing
ScrewGas
Valve
Combustion
Chamber
Gas
Valve
Nut
Close
Off Gas
Remove
Electrical
Connector
From
Electronic
Control Box
Remove
Gas
Pipe &
Boiler
Gas
Service
Cock
BB45022C
Fig. 21
now be brushed clean and any deposits falling through can
be swept out from the base of the boiler.
6.1 Preparation
1) Isolate the electrical supply to the boiler.
2) Isolate and remove the gas fire as shown in the gas fire
Installation & Service Instructions.
6.2 Burner/Gas Valve Assembly
1) Turn the gas supply Off at the boiler gas service cock
isolation point.
2) Disconnect the gas valve electrical connector from the
electronic control box and release the lead from the
clips.
3) Release the nut securing the gas service cock to the
gas valve.
4) Remove the two wing nuts and remove the combustion
chamber front.
5) Remove the screw securing the burner/gas valve
assembly to the base of the boiler.
6) Carefully withdraw the complete assembly away from
the boiler
Main Burner
(45 Model)
Gas
Valve
Main
Burner
Injector
BB45023B
Fig. 22
7) Re-assemble in reverse order. Ensure that the flange
on the burner end cap (See Fig. 24) locates under the
top hat bracket at the rear of the combustion chamber.
6.3 Main Burner Injector
1) Perform section 6.2
2) Unscrew the injector.
3) Re-assemble in reverse order.
Note: On re-assembly use a suitable sealing compound on
the threads. Take care not to block the injector
holes.