Potterton Profile User guide

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lOOe, fanned balanced flue gas fired boiler
THIS APPLIANCE IS FOR USE WITH NATURAL GAS (G20) ONLY
Installation and Servicing Instructions
LEAVE THESE INSTRUCTIONS ADJACENT TO THE GAS METER

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GAD (90/396/EEC)
POTTERTON PROFILE lOOe G.C. No. 41 -607-49 (S.I.T. Control Valve)
POTTERTON PROFILE lOOe G.C. No. 41-605-65 (White Rodgers Control Valve)
IMPORTANT This appliance must be installed and serviced by a competent person as stated in the Gas Safety (Installation
and Use) Regulations 1994.
Profile boilers are certified for safety, it is therefore important that no external control devices (e.g. flue dampers,
economisers, etc.) be directly connected to these appliances unless covered by these installation instructions or otherwise
recommended in writing. Any direct connection of a control device not approved by Potterton could invalidate the certificate
and the normal warranty.
LIST OF CONTENTS - Page 2
General
Optional Extras
Accessories
Installation Data
Boiler Dimensions
Page No. 2
Page No. 2
Page No. 3
Page No. 3
Page No. 3
Site Requirements
Technical Data
Installation Instructions
Commissioning
Health and Safely Information
Control Systems, Pipework and
Wiring Guide
User’s Instructions
Page No. 3
Page No. 6
Page No. 11
Page No. 18
Back Page
Supplied in
Literature Pack
GENERAL - Page 2
This Potterton Profile boiler is a fully automatically
controlled wall mounted fan powered balanced
flue appliance, using a cast iron heat exchanger
and is range rated from 23.44-29.3kW (80,000-
100,000 Btu/h) output.
The boiler which is designed to provide domestic
hot water and/or central heating must be used on
INDIRECT hot water systems only. The cast iron
heat exchanger, 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 boiler can be supplied with either of the following types
of flue system, these are packaged with the terminal and
associated flue components.
1) Standard Horizontal flue system Part No. 225542.
Suitable for a wall thickness from 100mm (4in.) to 51
0mm (2Oin.).
2) 1 metre horizontal flue system Part No. 225545. Which
provides a maximum flue length of 955mm (37 in.).
3) 1 metre vertical flue system Part No. 213050. Which
allows the flue to pass through a flat roof and terminate
at a maximum height of 980mm (38in.) measured from
top of the boiler case.
OPTIONAL EXTRAS - Page 2
The following are kits available as optional
extras:-
Internal Fitment Kit, Part No. 225184, which is
suitable for a maximum wall thickness of 510mm
(2Oin.) is to be used where access to the outside
wall is impracticable.
Pump Cover Kit, located on top of the boiler and
designed to conceal the pump, and/or any
motorised valves installed above the boiler (Note:
Pump cannot be fitted above the boiler if the
vertical flue kit is used).
The following sizes are available:-
6in. Part No.225418
7in. - l2in. Part No. 225419
l3in. - l8in. Part No. 225420
l9in. - 24in. Part No.225421
Terminal Wall Plate, Part No. 212280, where necessary
can be fitted to the outside wall face to improve the
appearance, after making good around the terminal.
Terminal Guard, Part No. 205792, to be used when the
terminal is fitted less than 2m above a balcony, above
ground or above a flat roof to which people have access.

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ACCESSORIES - Page 3
The following range of Potterton system controls are
also available and further information will be
provided on request.
Electronic Programmer E.P. 2001, E.P. 3001, E.P.
4001, E.P. 6000.
Programmable Electronic Thermostat PET 1.
Thermostatic Radiator Valve Myson
Electronic Cylinder Thermostat PTT2
Electronic Room Thermostat PRT2
Spring Return Zone Valve PMV2
Spring Return Diverter Valve PMV3
INSTALLATION DATA - Page 3
The installation of the boiler must be in accordance
with the latest relevant requirements of the Gas
Safety (Installation and Use) Regulations, local
building regulations, lEE Wiring Regulations and the
Byelaws of the Local Water Undertaking.
Detailed recommendations are contained in the
following British Standards and Codes of Practice.
B56798, B55440 Part 1
B55440 Part 2 B55449 Part1
BS5546 B54814. B56891.
BUILDING REGULATIONS.
MODEL WATER BYELAWS.
BRITISH GAS PUBLICATION DM2.
GAS SAFETY (INSTALLATION AND USE)
REGULATIONS.
BUILDING STANDARDS (SCOTLAND)
REGULATIONS.
BOILER DIMENSIONS - Page 3
SITE REQUIREMENTS - Page 3
The boiler is not suitable for external installation and
should not be fitted directly above a cooking
appliance. The boiler m be installed in any room,
although particular attention is drawn to the
requirements of the current I.E.E. Wiring Regulations
and in Scotland, the electrical provisions of the
Building Standards applicable in Scotland with
respect to the installation of the
appliance in a room containing a bath or shower.
Where a room-sealed appliance is installed in a room
containing a bath or shower, any electrical switch or
appliance control, utilising mains electricity should be so
situated that it cannot be touched by a person using the
bath or shower.

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Site Requirements - Page 4
FIG. 2 GENERAL ARRANGEMENT

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Site Requirements - Page 5
Where the installation of the boiler will be in an unusual
location, special procedures may be necessary and BS
6798 gives detailed guidance on this aspect.
Ensure that the gas supply pipe and meter are large
enough for this appliance and any others that may be run
off the same meter. Reference should be made to
B56891.
Boiler Mounting Surfaces
The boiler must be mounted on a flat wall, which may be of
combustible material and must be sufficiently robust to take
the weight of the boiler. The requirements of the local
authorities and the building Regulations must be adhered
to.
IMPORTANT NOTICE:
TIMBER FRAMED HOUSES
If the appliance is to be fitted in a timber framed building, it
should be fitted in accordance with British Gas Publication
‘Operational Procedures for Customer Service’ Part 19. If
in any doubt, advice should be sought from the local region
of British Gas.
Clearances Around the Boiler
The following minimum clearances must be maintained
after installation, for correct operation and servicing of the
boiler:
610mm (2 ft) at the front of the boiler
5mm (0.2 in) each side of the boiler
50mm (2 in) at the top (measured from the top of the boiler
case), except where the optional extra pump cover is to be
fitted, when 178mm (7 in) should be allowed.
100mm (4 in) at the bottom of the boiler.
Additional clearances to these are required during
installation for lifting the boiler and 127mm (5 in) is required
at the top of the boiler for access to the pipe connections.
Ventilation
If the boiler is to be installed in a confined space such as a
cupboard, the space will need ventilating. Openings must be
provided at the top and bottom of the cupboard each of
which should have a free area of 349 cm2, (54 in2). Further
details for installation of a boiler within a compartment are
giving in BS 6798.
If the openings draw air from outside the building the free
areas may be halved. Refer to BS 54401 Part 2 for further
guidance.
Balanced Flue Terminal and Ducting
The fresh air inlet and flue ducts can be run from either the
left, right, rear or top of the boiler to a miniature terminal on
the outside of the building.
The minimum spacings from the terminal to obstructions
and ventilation openings as shown in FIG. 3.. For
information appertaining to horizontal flue lengths
reference should be made to FIG. 4.
If a terminal is fitted less than 2m above a balcony, above
ground or above a flat roof to which people have access
then a suitable terminal guard should be fitted (P.l.L No.
205792).
Refer to B55440 Part 1 for further guidance.
Fig. 3 THE SITING OF BALANCED
FLUE TERMINALS
INFORMATION RELATING TO VERTICAL FLUING IS
PROVIDED WITH THE VERTICAL FLUE SYSTEM
PACK.
NOTE
Where a flue terminal is fitted less than 1000 from a plastic
or painted gutter or 500mm from painted eaves, an
aluminium sheild of 1000 length should be fitted to
underside of gutter or eaves.
Any car port or other add-on extension should consist of a
roof or a roof and one other wall. If it consists of a roof and
two other walls — the installation shall be treated as suspect
and further advice sought.
POSITION MINIMUM DISTANCE
mm
A. DIRECTLY BELOW AN OPENABLE
WINDOW, AIR VENT, OR ANY OTHER
VENTILATION OPENING. 300
B. BELOW GUTTER, DRAIN/SOIL PIPE 75
C. BELOW EAVES 200
D. BELOW A BALCONY OR CAR PORT ROOF 200
E. FROM VERTICAL DRAIN PIPES AND
SOIL PIPE 75
F. FROM INTERNAL OR EXTERNAL CORNERS 300
G. ABOVE ADJACENT GROUND OR BALCONY
LEVEL 300
H. FROM A SURFACE FACING THE TERMINAL 600
I. FACING TERMINALS 1,200
J. FROM OPENING (DOOR/WINDOW) IN
CARPOT INTO DWELLING 1,200
K. VERTICALLY FROM A TERMINAL ON
THE SAME WALL 1,500
LHORIZONTALLY FROM A TERMINAL ON
THE SAME WALL 300
M. ADJACENT TO OPENING 150

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REAR OR SIDE FLUEING - Page 6
FIG. 4 FLUE LENGTHS
MAXIMUM
LENGTH ‘X’
STANDARD FLUE
SYSTEM 510mm (20in)
1 METRE FLUE
SYSTEM 955mm (37in)
ELECTRICITY SUPPLY
A 240 volts ~ 50Hz, single phase electricity supply
fused to 3 amperes, must be provided in accordance
with the latest edition of the I.E.E. Wiring Regulations
and any other local regulations that may apply. The
current rating of the wiring to the boiler must exceed 3
amperes and have a cross sectional area of at least
0.75mm2 in accordance with BS 6500. Table 16.
The supply to the boiler and its associated
equipment should be controlled by a 3A fused
double pole switch (having at least 3mm contact
separation in both poles) so that complete isolation
from the supply can be achieved to enable servicing
work to be carried out in safety.
TECHNICAL DATA - Page 6
Maximum working head 30.5m (100 ft) Power consumption 80 watts
(excluding pump)
Minimum working head on
Fully Pumped systems 305mm (1 ft) Flow/Return connection 28mm copper
Minimum circulating head Gas supply connection Rc. 1/2 (1/2 in BSP
on Gravity systems 1.2m (4 ft) Female)
Gas supply pressure 20mbar Water Content 6.5 litre (1.43 gal)
Maximum Flow temperature 82ºCAppliance Weight-installed 63.5kg (140 Ibs)
Electricity supply 240v ~ 50Hz fused Appliance Weight-lift 54.5kg (120 Ibs)
at 3A
Internal Fuse T1A

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Technical Data - Page 7
INJECTOR
SIZE GAS RATE m3/h (ft3/h) INPUT kW(Btu/h) OUTPUT kW(Btu/h) BURNER PRESSURE mbar in wg
Min
Max
4.9mm 3.00(105.9)
3.31(117.0)
3.62(128.0)
32.1(109500)
35.4(121000)
38.8(132500)
23.5(80000)
26.4(90000)
29.3(100000)
10.0
12.0
14.0
4.0
4.8
5.6
CIRCULATION PUMP SELECTION
The resistance through the heat exchanger when operating
with a water flow rate producing an 11 0C temperature riseat
maximum boiler output are shown in TABLE 2. If other
controls, such as three-position valves are used in the
system, the resistance through them, quoted in their
manufacturer’s literature must be taken into account. The
pump may be fitted on either the flow or return and MUST
be wired directly to the boiler terminal block, see FIG. 24. It
must be fitted with two isolating valves which are positioned
as close to the pump as possible. Closing of any valve must
always leave the open vent unobstructed.
TABLE 2
WATER FLOW RATE BOILER RESISTANCE
WITH DISC WITHOUT DISC
litres/sec gal/min KN/m2 in wg KN/m2 in wg
0.637 8.4 17.8 72 5.2 21
NOTE: Great care should be taken when selecting a
pump to ensure that the correct flow rate is achieved.
Fully pumped systems should be designed so that the
system differential is no greater than 15ºC.
FIG. 5 PRESSURE LOSS ACROSS BOILER

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Technical Data - Page 8
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 are open
vented.
The system should be designed so that the maximum static head
does not exceed 30.5 m (lOOft) and a minimum on fully pumped
systems of 305 mm (1 ft). See FIG. 6.
Gravity domestic hot water circuits should have a minimum
circulating head of 1.2 m (4ft). See FIG. 8.
To ensure optimum boiler performance on both gravity hot water
and fully pumped systems a change-over switch is incorporated in
the boiler control box. The boiler is supplied with the switch set for
sealed or open vented fully pumped systems.
If the boiler is to be used on a system with gravity hot water the
switch should be set at the GRAVITY position. In addition the bulb
of the overheat thermostat should be repositioned as shown in
FIG. 21 b.
To prevent reverse circulation in the gravity circuit when the pump
is running an injector disc is provided to form an injector tee at the
return connection on the boiler. See FIG. 20.
On all systems the pump should be wired to the boiler terminal
block. To prevent nuisance operation of the overheat thermostat, it
is important that where electrically operated zone valves are used
the boiler is wired so it does not cycle when the zone valves are
closed. Also, systems fitted with controls that close both hot water
and central heating circuits while the boiler is still hot, must be fitted
with a by-pass circuit to dissipate the residual heat within the boiler.
Further information on by-pass arrangements is provided in later
notes and illustrations.
Drain off taps should be fitted in the pipework close to the boiler
and in the low points of the system.
Note: Although the system can be emptied using the drain off taps
installed in the pipework around the system, to empty the boiler it is
necessary to remove the drain off cap positioned within the boiler
case. See FIG. 2.
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 by installed in the gravity circuit. A suggested method of
doing this is shown in FIG. 8 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.
Fully pumped Systems
NOTE: Great care should be taken when selecting a pump to
ensure that the correct flow rate is achieved. Fully pumped systems
should be designed so that the system differential is no greater than
15ºC.
With the change-over switch in the control box set at the FULLY
PUMPED position, the pump will be controlled by an over-run
thermostat. This will ensure that the pump will continue to run after
boiler shut down if the water temperature in the boiler is high. If a
three port diverter valve is used as shown in FIG. 6, a by-pass is
not necessary since one circuit is always open.
temperature in the boiler is high, thus preventing nuisance
operation of the overheat thermostat. If a three port diverter
valve is used as shown in FIG. 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. The total length of the by-pass circuit taken from the
boiler connections should be greater than 4 metres of 22 mm
pipe. It should be fitted with a lockshield valve and be adjusted to
maintain a minimum flow through the boiler of 4.5, litres/mm (1
gal/mm) see Figs. 6, 7.
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 1 kW (3400 Btu/h)
2. Maintaining a minimum water flow through the boiler of 9
litres/mm (2 gal/mm).
A suggested method of meeting these requirements by using a
bathroom radiator fitted with two lockshield valves is shown in
FIGS. 6, 7.
Additional system information can be found in the Control
Systems, Pipework and Wiring Guide.
SEALED SYSTEMS (FULLY PUMPED)
InstallatIon
The installation must comply with the requirements of
BS 6798 and BS 5449 Part 1. The B.G. 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 Part
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 Part 1 shall be
fitted close to the inlet side of the pump. The connecting
pipework should not be less than 15 mm (1/2 in nominal).
Pipework connecting the expansion vessel should not
incorporate valves of any sort. Methods of supporting the vessel
are supplied by the 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). 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.

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Technical Data - Page 9
Boiler Heat Exchanger: 6.5 litres Cylinder
Small Bore Pipework: 1 litre per kW of The hot water cylinder must be an indirect coil type or a
system output direct cylinder fitted with an immersion calorifier
suitable for operating at a gauge pressure of 0.3 bar
Micro Bore Pipework: 7 litres (5lbf/in2) in excess of safety valve setting. Single feed
indirect cylinder are not suitable for sealed systems.
Steel Panel Radiators: 8 litres per kW of
system output Method of Make-Up
Low Water Capacity Radiators: 2 litres per kW of Provision shall be made for replacing water loss
system ouput from the system either:-
i) from a make-up vessel or tank mounted in a
Hot water Cylinder: 2 litres position higher than the top point of the system,
and connected through a non-return valve to the
If the system is extended, the expansion vessel volume system on the return side of hot water cylinder
may have to be increased unless previous provision has or the return side of all heat emitters.
been made for the extension. Where a vessel of the or
calculated size is not available, the next available larger
size should be used. The boiler flow temperature is ii) where access to a make-up vessel would be
controlled at approximately 82ºC. difficult by using the mains top up method or
a remote automatic pressurisation and make-up
unit as sillustrated in FIG. 7 METHODS 1 and 2.
The vessel size can now be determined from the following
table where V=System volume in litres. Mains Connection
Vessel Charge Pressure (bar) 0.5 1.0 There shall be no connection to the mains water
Initial System Pressure (bar) 1.0 1.0 supply or to the water storage tank which supplies
Expansion Vessel Volume (litres) Vx0.11 Vx0.087 domestic water even through a non-return valve,
without the approval of the local Water Authority.
Further guidance is given in BS 5449 Part 1 or BS 7074
Part 1. Filling Point
The system shall be fitted with a filling point at low
level which incorporates a stop valve to BS1010
and a double check valve (approved by the National
Water Council) to be fitted in this order from the
system mains, Refer to FIG. 7. Method 1.
FIG. 6 OPEN VENTED FULLY PUMPED SYSTEM
FITTED WITH A COMBINED FEED AND VENT

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Technical Data - Page 10
Fig 7
Fig 8

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INSTALLATION INSTRUCTIONS - Page 11
It is the law that all gas appliances are installed and serviced
by Competent persons as stated in Gas Safety (Installation
and Use) Regulations 1994.
For Health and Safety information see back page.
Electrical installation and servicing should be carried out by
a competent person in accordance with the I.E.E. Wiring
Regulations.
The boiler and its associated equipment will arrive on site in
two cardboard cartons. The contents of each carton is as
follows.
CARTON 1:-
Boiler
Template
Literature Pack Containing:-
Installation and Servicing Instructions
User’s Instructions
Control Systems Pipework and Wiring Guide
Auxiliary Pack Containing:-
Boiler Mounting Bracket
Gas Service Cock and Accessory Packs
Spring Clip
CARTON 2, FLUE SYSTEM PACK:-
STANDARD OR 1 METRE HORIZONTAL FLUE
SYSTEMS
Air/Flue Duct Assembly (length as ordered)
Flue Elbow Extension
Flue Terminal
Flue Sealing Collar
Rope Sealing Ring
Side Infill Panels-2 off
1 METRE VERTICAL FLUE SYSTEM (consists of two
cartons)
Air/Flue Duct Assembly
Flue Terminal
Side Inf ill Panels-2 off
Terminal Cowl
Vertical Flue Adapter
Accessory Pack
Flue Installation Instructions
Optional Components will be supplied in Separate
Cartons
Fig. 9 TEMPLATE
Place template in proposed boiler position ensuring it is level
(the minimum side clearances are automatically allowed for).
REAR FLUING
Mark holes ‘A’, ‘B’, ‘D’, age flue outlet hole and side of boiler
reference lines through slots ‘C’.
SIDE FLUING
Mark holes positions ‘A’, ‘D’ and side of boiler reference
lines through slots ‘C’.
Extend Horizontal line from top of the boiler to side wall.
Mark large flue outlet hole and holes ‘B’ using the thick lines
on the template for minimum clearance at the rear of the
boiler and the thin dotted lines for maximum clearance. See
NOTE on FIG. 1.
Fig. 10 BOILER MOUNTING PLATE
Remove template and carefully cut flue outlet hole
through wall. If necessary make good around hole to
enable holes ‘B’ to be drilled. (If internal flue fitment kit is
being used refer to instructions supplied with kit).
Drill holes ‘A’ using a 7 mm drill
Drill holes ‘B’ and ‘D’ using a 5 mm drill
Using wall plugs, screws and washers (accessory pack A)
attach boiler mounting plate to wall. Ensure that it is level
and the correct way up, i.e. to provide the clearance at the
rear of the boiler allowed for when marking out using the
template. See also NOTE on FIG. 1.
Insert wall plugs into holes ‘B’ (accessory pack B) and
hole ‘D’ (accessory pack D). Bend the tags to 90 deg. and
insert flue sealing collar into wall and secure with screws
and washers provided, (accessory pack B). Make good
the internal wall surface around flue sealing collar.

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Installation Instructions - Page 12
Fig. 11a SIDE FLUE
1. Measure from outside face of wall to the side of boiler
casing reference line (dimension ‘x’).
2. Take air/flue duct assembly and measuring from the
flanged end, mark and cut the outer duct and inner flue
duct to dimension ‘x’ plus 20mm. Ensure that both
ducts are cut squarely.
Fig. 11b REAR FLUE
1. Measure wall thickness (dimension ‘Y’).
2. Take air/flue duct assembly and measuring from the
flanged end, mark and cut the outer air duct and inner
flue duct to dimension ‘Y’, plus 45 mm. Ensure that
both ducts are cut squarely.
NOTE
Cutting length remains the same for minimum or
maximum clearance at the rear of the boiler.
Fig. 12 AIR/FLUE DUCT ASSEMBLY
1. Slide rope sealing ring on to air duct.
2. Engage the terminal on to the ends of the inner flue
duct and press fully home.
3. Engage four screws from accessory pack ‘C’ into the
pre-drilled holes in the terminal and screw fully home.
These screws which are self drilling will pierce the air
duct and secure the terminal to air duct.

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Installation Instructions - Page 13
FIG. 13 SECTIONAL VIEW OF AIR/FLUE
DUCT ASSY THROUGH WALL
4. Protect duct where it is likely to come into contact with
wet mortar by using adhesive tape provide (accessory
pack E).
5. Insert the assembly into the wall sliding the rope
sealing ring along the air duct into the flue sealing
collar. Bend the six tabs on flue sealing collar inwards
to retain the rope sealing ring. Ensure air duct flange
studs do not obstruct lifting of boiler onto mounting
bracket and that the vanes of terminal are pointing in
the desired direction.
FIG. 14 PREPARING BOILER
The controls cover should have been removed when
unpacking the boiler, if not remove controls cover by
opening the door covering the securing screw on the
underside of the controls cover, see FIG. 14. Undo
securing screw, pull controls cover forward 10mm, lower to
release from the four side fixings and pull forward clear of
the thermostat knob.
Remove door by undoing the two lower fixing screws and
lift door off the two upper hinge brackets.
Remove the screws securing the combustion chamber front
panel and remove panel.
Disconnect the fan supply leads from the connector
adjacent to the fan. Leaving in place the three screws
identified with a red circle or adjacent ‘F’ mark in Fan
Plate, remove the remaining screws securing the fan
mounting plate and remove the mounting plate complete
with fan.
Disconnect the two flexible tubes from the flue elbow.
Remove the four brass securing nuts and lift off the flue
elbow, taking care not to damage the gasket.
NOTE:
If side fluing, loosen the two brass securing nuts beneath
the flue elbow outlet and remove the other two. Tilt the
flange and withdraw the elbow.
The boiler is supplied with the left hand flue outlet sealing
plate removed. If another flue outlet direction is required,
remove the appropriate flue outlet sealing plate and
transfer it to the left hand position.

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Installation Instructions - Page 14
LIFTING THE BOILER
Lift the boiler onto its mounting bracket.
FIG. 15
Position boiler on its mounting bracket so that the sides of
the boiler line up with the reference lines ‘C’ on the rear
wall.
Undo the two screws securing the transportation foot and
discard foot. Vertical alignment with rear wall can be
corrected using the adjustment screws at the rear of the
boiler. See FIGS. 16 & 17.
FIG. 16 TRANSPORTATION FOOT
Locate the studs on the air duct flange through the boiler
casing and secure using four wing nuts (accessory pack
F).
Fig. 17 SECURING BOILER
Rotate the left hand adjustment screw to align one of the
holes in the base plate with hole ‘D’ in the wall. Working
through the hole in the leg, secure the base plate to the
wall using the screw from accessory pack ‘D’.
Make good the wall surface around the flue terminal. Fit
optional terminal wall plate if required.
Fig. 18 FLUE ELBOW EXTENSION
When side fluing, slide the elbow extension on to the elbow
and ensure that it is pushed on fully. Engage the screw
from accessory pack ‘C’ into the pre-drilled hole in the
elbow extension and screw fully home. The screw which is
self drilling will pierce the elbow and secure the extension
to the elbow.
When rear fluing, the elbow extension should be discarded.

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Installation Instructions - Page 15
FIG. 19 LOCATION OF PRESSURE
SENSING TUBES
If the boiler is to be used on a gravity DHW system
refer to Page 16, overheat thermostat positioning
before fitting the flue elbow.
Slide the flue elbow into the flue duct and locate the
flange over the studs on the fluehood ensuring that
the sealing gasket is in place. Secure the elbow to
fluehood using the four brass securing nuts.
Reconnect flexible tubes to elbow. ENSURE THEY
ARE NOT KINKED. NOTE: Red tube connects the
front aluminium tube in upper chamber to the lower
connection on elbow, each being identified with a
red ring.
FIG. 20B
FIG 20. PIPE CONNECTIONS
Connect system pipework to the boiler, compression
fittings are recommended. A drain off tap should be
installed close to the boiler if it is in a low point of the
system.
On combined gravity hot water/pumped central heating
installations the flow and return pipes for both the gravity
hot water circuit and pumped central heating circuit must
be connected to tees fitted directly to the flow and return
pipes on the boiler
The gravity circuit should be installed in 28mm copper
pipe. 28mm tees should be used.
The injector disc (accessory pack H) must be positioned in
the pumped return branch of the tee and the pipes
connected to the tees as illustrated in Figs. 20 and 20B.
Two discs are provided, use the larger and discard the
other.
Connect the gas supply pipe to the inlet of the gas cock,
connect the boiler service cock to the inlet of the gas valve.
Ensure that the gas cock is in a position where it can be
easily operated when the controls cover is removed.
WARNING: UNDER NO CIRCUMSTANCES SHOULD A ‘REDUCING SET’ BE FITTED

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16
Installation Instructions - Page 16
OVERHEAT THERMOSTAT POSITIONING
Fig. 21A FULLY PUMPED POSITION Fig. 21B GRAVITY DHW POSITION
If the boiler is fitted with a right hand flue, remove flue
elbow as described in Section 1 preparing the Boiler for
Servicing operations F, G, page 22.
NOTE: This boiler is dispatched with the overheat
thermostat bulb positioned for FULLY PUMPED OPEN
VENTED OR SEALED systems. ONLY if the boiler is to be
used on a GRAVITY DHW system should the bulb of the
overheat thermostat be repositioned as described below, to
prevent nuisance operation of the overheat thermostat. If
boiler is fitted to a fully pumped system the spring clip in the
auxiliary pack can be discarded.
1. Remove split pin retaining overheat thermostat (Fig.
21A) and pull bulb from pocket along with spacer,
discard spacer and split-pin.
2. Carefully remove excess heat conductive paste from
bulb.
3. Remove split grommet at the top right hand side of the
casing (Fig. 21 B).
4. Carefully uncoil capillary and pass bulb through
grommet retaining hole, then attach to return pipe
using spring clip contained in auxiliary pack.
5. Refit grommet ensuring that it makes a good seal
around the capillary. Ensure that the capillary is secure
in clips provided. Refer to Fig. 2.
6. ENSURE that the system change-over switch in the
control box is set in GRAVITY DHW position.
ELECTRICAL
The boiler and all external control circuit wiring must be
supplied from the same single isolating switch and should
be fused at 3A.
Care must be taken to ensure that all wiring to the boiler is
kept clear of sharp edges and hot surfaces.
FIG. 22 PRINCIPLE OF WIRING
FIG. 23 ACCESS TO THE BOILER ELECTRICAL
TERMINAL BLOCK
The boiler terminal block which is situated in the control
box is not designed to accept wiring from all the on site
controls and therefore the installer will usually need to
incorporate a suitable junction box. This may not be
required if a Potterton Electronic Programmer is used as
this incorporates a junction box. The principle of wiring is
shown in FIG. 22.
Further information on wiring of system controls can be
found in the Control System, Pipework and Wiring Guide.
Remove control box securing screw and lower the control
box to gain access to the boiler terminal block.

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17
Installation Instructions - Page 17
FIG. 24 ROUTING OF ELECTRICAL WIRING
Following the pump manufacturer’s instructions connect the
pump supply wires to terminals marked PUMP L, N, on
the boiler terminal block. Route the cable through the
plastic bush in the rear of the control box as illustrated in
FIG. 24 and secure, using the cable clamp.
Route a four core cable through the plastic bush in the rear
of the control box and the cable clamp as illustrated in FIG.
24 and connect it to the boiler input terminals as follows:—
Fully Pumped Systems.
Permanent live to terminal marked MAINS ‘L’.
Neutral to terminal marked MAINS ‘N’.
Earth to terminal marked .’ ’ adjacent to cable clamp.
See NOTE.
Switched live from external controls to terminal marked
MAINS ‘SwL’.
If there are no external controls fitted connect the SwL
terminal to permanent live in the junction box.
Gravity Domestic Hot Water/Pumped Central
HeatIng Systems.
Switched live from external gravity domestic hot water
control circuit to terminal marked MAINS ‘SwL’. Switched
live from external pumped central heating control circuit to
terminal marked MAINS ‘L’.
Neutral to terminal marked MAINS ‘N’.
Earth to terminal marked ‘ ’adjacent to cable clamp.
See NOTE.
If there are no external controls fitted connect the SwL and
L terminals to permanent live in the junction box.
NOTE:
Ensure that the earth conductor is longer than the L, N &
SwL from the point of anchorage, so that the current
carrying conductors become taut before the earth
conductor if cable is pulled out of the cable clamp. When
the wiring has been completed close the control box and
replace the securing screw.
FITTING SIDE INFILL PANELS
If required, the gap between the casing sides and rear wall
can be closed off using the infill panels supplied.
Ensure the casing surface is FULLY CLEAN AND DRY.
Remove the protective backing paper from the adhesive
strip on the infill panel, carefully align and press into place,
applying FIRM EVEN pressure down the FULL LENGTH of
contact area between panel and case. If conditions are
near freezing, the boiler case should be warmed prior to
application of the infill panel.
FIG. 25

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COMMISSIONING - Page 18
Open Vented Systems
Remove the pump and flush out the system thoroughly with cold
water. Refit the pump. Fill and vent the system. Examine 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 ‘THE SYSTEM’ section Page 8 in these
instructions, also B56798 1987.
Remove pump and flush out the system thoroughly with cold
water. Refit the pump. Fill and vent the system until the pressure
gauge registers 1.5 bar (21.5 lbf/in2). Examine 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, and set the indicator on the water gauge
to this value.
All Systems
Refit the fan assembly and reconnect the fan supply leads,
(polarity of the fan leads is not important).
The whole of the gas installation including the meter should be
inspected and tested for soundness and purged in accordance
with the recommendations of BS 6891.
Test pilot unions for gas soundness as follows:—
Turn boiler thermostat to the ‘O’ position.
Unplug the gas control valve supply lead from the control box and
plug it into the test socket adjacent to the boiler thermostat knob,
see FIG. 24.
Turn on gas at the gas service cock.
Ensure that the time control if fitted is in an ON condition, and that
the room and/or cylinder thermostats where fitted are set to high
temperatures.
Switch on the external electricity supply to the boiler.
Gas will flow to the pilot only. It will not be ignited as the ignition
system is de-energised.
Using a leak detection fluid, check pilot unions for gas soundness.
Turn off the external electricity supply and gas service cock.
Remove gas control valve plug from the test socket and
refit the plug into the socket on the left hand side of the control
box see FIG. 24.
Refit the combustion chamber front panel.
Fit the case door into position by lifting it onto the top hinge
brackets and secure it with the lower two fixing screws.
Remove the temporary label from the front of the casing, having
checked compliance with the information it contains.
First Lighting
WARNING: Before lighting the boiler, ensure that the CASE
DOOR HAS BEEN CORRECTLY FITTED and that the sealing
strip fitted to the case door is forming a tight seal with the main
boiler casing. Before proceeding to light the boiler, check that the
external electricity supply to the boiler is switched off and that the
boiler thermostat is in the ‘0’ position.
Turn on the gas service cock.
Ensure that the pump and radiator isolating valves are open.
Ensure that the time control, if fitted is in an on condition, and that
the room and/or cylinder thermostats, where fitted are set to high
temperatures.
Switch on to the external electricity supply to the boiler.
After installation of the appliance, preliminary electrical system
checks must be carried out. The checks to be carried out are:-
A. Earth Continuity
B. Short Circuit
C. Polarity
D. Resistance to Earth
Refer to Fault Finding Chart FIG. 31
Turn the boiler thermostat on and to a high setting and after a
period of time the main burner will light, this can be observed
through the sight glass in the front cover of the boiler. The time
period can vary upwards of 45 seconds, depending on the amount
of air in the pipework.
Test for gas soundness around the boiler components using leak
detection fluid.
Turn the boiler thermostat to ‘0’.
NOTE:
There could be a delay in lighting if the control knob is switched
on and off and then on again rapidly.
SETTING AND CHECKING OF CONTROLS
With the controls cover removed.
Fit a pressure gauge to the pressure test nipple in burner supply
pipe. See FIG. 2.
Turn on the boiler thermostat and ensure that the main burner is
alight. Check that the burner pressure is in accordance with values
stated under TECHNICAL DATA.
The burner pressure is set to the maximum output at the factory.
If burner pressure adjustment is necessary proceed as follows,
referring to FIG. 26.
S.l.T. Valve - Remove the plastic cover from the valve and turn
the screw beneath clockwise to decrease the pressure or anti-
clockwise to increase the pressure.
White Rodgers Valve - Remove the brass cover screw from the
gas control valve and turn the screw beneath clockwise to
increase the pressure or anticlockwise to decrease the pressure.

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Commissioning - Page 19
FIG. 26 MAIN BURNER PRESSURES ADJUSTMENT
With the burner set to its correct pressure, the firing rate
given in TECHNICAL DATA should also be obtained and
this should be checked by meter reading at least 10
minutes after the main burner has been lit. When the
pressure and rate are correct, replace the adjustment
screw cover.
Shut down the boiler remove the pressure gauge and refit
the screw in the test nipple ensuring that a gas tight seal is
made.
Remove the self-adhesive arrow from the inspection ticket
tied to the burner supply pipe and stick it to the Data Plate
inside the controls cover to indicate the appropriate burner
setting pressure.
Refit the controls cover, and secure with screw.
Relight the boiler and heat the system to maximum. Check
for water leaks, turn the boiler off, drain the system whilst
hot.
Refill the system and 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 operating conditions.
Pilot Burner
The pilot is pre-set and no adjustment is required. The pilot
flame envelope should cover the electrode tip and spark
earthing strip see FIG. 30. If the pilot flame is not as
illustrated, remove and clean the pilot as described in the
Servicing Instructions Section 3, PILOT BURNER, Page
22.
Boiler Thermostat
At its minimum and maximum settings, the thermostat
should control the water flow temperature at approximately
55ºC-82ºC (130ºC-180ºF).
The thermostat has been calibrated by the makers and no
attempt should be made to re-calibrate it on site. Turn on
the boiler thermostat and ensure that the main burner is
alight. Turn the thermostat to the ‘O’ position and check
that the main burner shuts down.
Gravity Hot Water/Pump Over-Run Thermostat
The function of this thermostat is determined by the
position in which the GRAVITY/FULLY PUMPED SYSTEM
selection switch is set. The thermostat is preset and no
adjustment is possible.
On the FULLY PUMPED switch position it will operate as a
pump over-run thermostat and will keep the pump running
after the boiler has shut down, as long as the water
temperature within the boiler is above approximately 80ºC.
On the GRAVITY switch position it will operate in series
with the boiler thermostat when only the gravity domestic
hot water circuit is in operation.
It will over-ride the boiler thermostat when the water
temperature within the boiler is above 80ºC.
Overheat Thermostat
The overheat thermostat is pre-set and no adjustment is
possible. It will require manually resetting if an overheat
condition occurs. Access to the reset button is through a
hole in the underside of the controls cover, see
FIG. 2.
NOTE: Interruption of the electrical supply to the boiler may
also cause the overheat limit thermostat to operate.
Other Boiler Controls
All boiler mounted controls are designed so that if any fault
should occur they will fail safe. No further setting or
checking is necessary.
External Controls
Check that any other external control connected in the
system, such as clocks and thermostats, control the boiler
as required.
User’s Instructions
A User’s Instructions leaflet is provided with this boiler but
the householder must have the operation of the boiler and
system explained by the Installer. The householder must
also be advised of the importance of annual servicing and
of the precautions necessary to prevent damage to the
system and building, in the event of the system remaining
out of commission in frost conditions.

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Commissioning - Page 20
Fig. 27 FUNCTIONAL FLOW DIAGRAM
Fig. 28 BOILER WIRING DIAGRAM