Potterton Promax 15 HE Installation and maintenance instructions

Installation & Service Instructions Promax
15 HE & 24 HE
This is a Wall Mounted Powered Flue Condensing Boiler Gas Fired Central Heating Unit.
The boiler meets the requirements of Statutory Instrument “ The Boiler (Efficiency) Regulations 1993 No3083” and is
deemed to meet the requirements of Directive 92/42/EEC on the energy efficiency requirements for new hot water
boilers fired with liquid or gaseous fuels:-
Type test for purpose of Regulation 5 certified by:
Notified Body 0086.
Product/Production certified by:
Notified Body 0086.
For use with Natural Gas (G20) only at 20mbar and for use in GB/IE only.

Publication No. 5106451
2
Natural Gas
Potterton Promax 15 HE
G.C.No41 590 58
Potterton Promax 24 HE
G.C.No41 590 62

3
CONTENTS
Publication No. 5106451
0.0 Legislation 4
1.0 Introduction 5
2.0 General Layout 6
3.0 Appliance Operation 7
4.0 Technical Data 8
5.0 Dimensions and Fixings 9
6.0 System Details 10
7.0 Site Requirements 13
8.0 Installation 19
9.0 Electrical 25
10.0 Commissioning 27
11.0 Outer Case 28
12.0 Servicing 29
13.0 Changing Components 31
14.0 Fault Finding 38
15.0 Short Parts List 43
Section Page

0.0 LEGISLATION
4Publication No. 5106451
Codes of Practice, most recent version should
be used
IMPORTANT - Installation, Commissioning, Service & Repair
This appliance must be installed in accordance with the manufacturer’s
instructions and the regulations in force. Read the instructions fully before
installing or using the appliance.
In GB, this must be carried out by a competent person as stated in the Gas
Safety (Installation & Use) Regulations.
Definition of competence: A person who works for a CORGI registered
company and holding current certificates in the relevant ACS modules, or
valid ACoP equivalents, is deemed competent.
In IE, this must be carried out by a competent person as stated in I.S. 813
“Domestic Gas Installations”.
Lifting - This product should be lifted and handled by two people. For
recommended hand holds see section 8.3. Stooping should be avoided and
protective equipment worn where necessary. Carrying & lifting equipment
should be used as required, e.g. when installing in a loft space.
The addition of anything that may interfere with the normal operation of the
appliance without express written permission from the manufacturer or his
agent could invalidate the appliance warranty. In GB this could also infringe
the Gas Safety (Installation and Use) Regulations.
Warning - Check the information on the data plate is compatible with local
supply conditions.
“Benchmark” Log Book
As part of the industry-wide “Benchmark”initiative all Potterton boilers now
include an Installation, Commissioning and Service Record Log Book. Please
read the Log Book carefully and complete all sections relevant to the
appliance and installation. These include sections on the type of controls
employed, flushing the system, burner operating pressure etc. The details of
the Log Book will be required in the event of any warranty work. Also, there is
a section to be completed at each subsequent regular service visit. The Log
Book must be left with the user.
All CORGI registered installers carry a CORGI identification card and have a
registration number. Both should be recorded in your boiler Log Book. You
can check your installer is registered by telephoning [phone] or
writing to:-
1 Elmwood,
Chineham Business Park,
Crockford Lane,
Basingstoke. RG24 8WG
Potterton declare that no substances harmful to
health are contained in the appliance or used
during appliance manufacture.
The appliance is suitable only for installation in GB
and IE and should be installed in accordance with
the rules in force, and only used in a suitably
ventilated location.
In GB, the installation must be carried out by a CORGI
Registered Installer. It must be carried out in accordance
with the relevant requirements of the:
•Gas Safety (Installation & Use) Regulations.
•The appropriate Building Regulations either The
Building Regulations, The Building Regulations
(Scotland), Building Regulations (Northern Ireland).
•The Water Fittings Regulations or Water Byelaws in
Scotland.
•The Current I.E.E. Wiring Regulations.
Where no specific instructions are given, reference
should be made to the relevant British Standard Code of
Practice.
In IE, the installation must be carried out by a competent
Person and installed in accordance with the current
edition of I.S. 813 ‘Domestic Gas Installations’, the
current Building Regulations and reference should be
made to the current ETCI rules for electrical installation.
All systems must be thoroughly flushed and
treated with inhibitor (see section 6.2).
In GB the following Codes of Practice apply:
Standard Scope
BS 6891 Gas Installation.
BS 5546 Installation of hot water supplies for
domestic purposes.
BS 5449 Forced circulation hot water systems.
BS 6798 Installation of gas fired hot water boilers.
BS 5440 Part 1 Flues.
BS 5440 Part 2 Ventilation.
BS 7074 Expansion vessels and ancillary equipment
for sealed water systems.
BS 7593 Treatment of water in domestic hot water
central heating systems.
In IE the following Codes of Practice apply:
Standard Scope
I.S. 813 Domestic Gas Installations.
The following BS standards give valuable additional information;
BS 5546 Installation of hot water supplies for
domestic purposes.
BS 5449 Forced circulation hot water systems.
BS 7074 Expansion vessels and ancillary equipment
for sealed water systems.
BS 7593 Treatment of water in domestic hot water
central heating systems.

5
1.0 INTRODUCTION
Publication No. 5106451
1.1 Description
1. The Potterton Promax 15 HE and 24 HE are gas
fired room sealed fan assisted condensing central
heating boilers.
2. The maximum output of the Potterton Promax 15
HE is 52,000 Btu/hr. The maximum output of the
Potterton Promax 24 HE is 75,000 Btu/hr. Both
boilers automatically adjust their outputs down to
30,000 Btu/hr according to the system load.
3. It is designed for use on Natural Gas (G20).
4. The boiler is suitable for fully pumped open vented
central heating and domestic hot water systems and
sealed systems.
5. A label giving details of the model, serial number
and Gas Council number is situated on the top of the
outercase (Fig. 1).
6. The boiler data badge is positioned on the air box
door (Fig. 2).
7. The boiler is intended to be installed in residential /
commercial / light industrial E.M.C. environments on
a governed meter supply only.
8. The boiler must be installed with one of the
purpose designed flues such as the standard
horizontal flue kit, part no 236921.
1.2 Important Information
Man-made mineral fibre
•Some component parts of this appliance (insulation
pads, gaskets and rope seals) are manufactured
from man-made mineral fibre.
•Prolonged or excessive exposure to this material
may result in some irritation to the eyes, skin or
respiratory tract.
•It is advisable to wear gloves when handling these
items.
•Irritant dust will only be released from the items if
they are broken up or subjected to severe abrasion.
In these instances a suitable dust mask and goggles
should be worn.
•Always thoroughly wash hands after installation,
servicing or changing components.
•When disposing of any items manufactured from
man-made mineral fibre care must be exercised.
•If any irritation of the eyes or severe irritation of the
skin is experienced seek medical attention.
Fig. 1
Data Badge
Air Box Door
Fig. 2
Label

2.0 GENERAL LAYOUT
6Publication No. 5106451
2.1 Layout (Figs. 3,4 & 5)
1. Wall Plate
2. Flue Elbow
3. Heat Exchanger
4. Burner
5. Air Box
6. Fan Protection Thermostat
7. Fan Assembly
8. Condensate Trap
9. On/Off/Lockout Reset Switch
10. Gas Tap
11. Gas / Air Ratio Valve
12. Electronics Housing
13. Transformer
14. Flow Pipe Connection
15. Return Pipe Connection
16. Flow Temperature Safety Thermostat - Black
17. Flow Temperature Thermistor - Red
18. Flow Switch (dry fire protection)
1
2
3
4
5
6
7
9
8
10
11
12
13
17 16
14
15
18
Fig. 4
Fig. 3
Fig. 5
2.2 Optional Extras
KIT PART No
FLUE EXTENSION KITS (110/70)
Flue Extension 0.25M 241692
Flue Extension 0.5M 241694
Flue Extension 1M (Use two kits for 2M etc.) 241695
Flue Bend x 2 - 45°(Reduce overall length of flue
by 0.5m when fitting this bend) 241689
Flue Bend - 90°(Reduce overall length of flue
by 1m when fitting each bend) 241687
Horizontal Extended Flue (1.75M) 5111457
VERTICAL FLUE (110/70)
Vertical Flue Terminal 242802
Vertical Flue Adaptor 5106888

7
3.0 APPLIANCE OPERATION
Publication No. 5106451
3.1
1. Switched Live On: When the switched live
switches on pump overrun occurs.
2. Pump Overrun: The pump is on while the fan,
spark generator and gas valve are off. If at any stage
during pump overrun the flow temperature is less
than the set point and the flow switch is made then
fan purge occurs. After 1 minute of pump overrun
anti-cycle occurs.
3. Fan Purge: The pump and fan are on while the
spark generator and gas valve are off. After 5
seconds ignition occurs.
4. Ignition: The pump, fan, spark generator and gas
valve are on. If a flame is detected then burner on
occurs. If a flame is not detected within 5 seconds
and less than 5 ignition attempts have been made
then fan purge occurs. If a flame is not detected
within 5 seconds and 5 ignition attempts have been
made the ignition lockout occurs.
5. Burner On: The pump, fan and gas valve are on
while the spark generator is off. Flow temperature is
controlled by varying the fan speed (and thereby the
gas rate) to achieve optimum operation. If the flow
temperature is greater than the set point then pump
overrun occurs. If the TRVs all shut down then anti-
cycle occurs.
6. Anti-cycle: The pump, fan, spark generator and
gas valve are switched off. After 3 minutes pump
overrun occurs.
7. Ignition Lockout: The pump, fan, spark generator
and gas valve are switched off. The boiler can only
be reset by manually using the thermostat knob.
Mains On.
Flow
temperature less
than set point and flow
switch made ?
YES
5 second
Fan Purge.
Flame Detected ?
Burner On. Ignition
Lockout.
5 second
Ignition Period.
All TRVs
shut down ?
Flow temperature
greater than set
point ?
Ignition done and
5 attempts made ?
Ignition done
and less than 5
attempts made ?
Pump Overrun
Anti-cycle.
Pump Overrun
for 1 minute ?
YES
YES
YES
YES
YES
YES

4.0 TECHNICAL DATA
8Publication No. 5106451
Appliance Category CAT I 2H
Horizontal
Flue Terminal Diameter 110mm
Dimensions Projection 150mm
Outercase Dimensions
Overall Height Inc Flue Elbow - 750mm
Casing Height - 600mm
Casing Width - 390mm
Casing Depth - 320mm
Weights kg lb
Packaged Boiler Carton 40.7 89.6
Packaged Flue Kit 3.6 8.0
Weight Empty 38.2 84.1
Installation Lift Weight 31.5 69.3
Connections
Gas Supply - 1/2in BSPT
Central Heating Flow (HE15) - 28mm
Central Heating Flow (HE24) - 28mm
Central Heating Return (HE15) - 28mm
Central Heating Return (HE24) - 28mm
Condensate Drain - 1 in BSP
Recommended System
Temperature Drop
Normal 11°C20°F
Condensing 20°C36°F
Heat Input (see note) Max Min
15 HE kW 16.88 10.2
Btu/hr 57,600 34,840
24 HE kW 24.50 10.2
Btu/hr 83,600 34,840
Heat Output
(Non Condensing 70°C Mean Water Temp)
Max Min
15 HE kW 15.24 9.14
Btu/h 52,000 31,180
24 HE kW 22.0 9.14
75,000 31,180
Electrical Supply 230V~ 50Hz
(Appliance must be connected to an
earthed supply)
Power Consumption 80W
External Fuse Rating 3A
Internal Fuse Rating (BS 4265)
Fuse (2) 4 AT (Control Board)
Fuse (3) 2 AT (Ignition Board)
Max Gas Rate (Natural Gas)
(After 10 Mins)
Btu/hr 75,000 52,000
m3/h 2.31 1.64
ft3/h 83.3 52.1
Inlet Pressure at Gas Valve (Natural Gas)
Min 18.1 mbar
Max 22.5 mbar
(see Section 10.1)
Injector (Natural Gas)
6.3mm Diameter
Clearances
Both Sides 5mm Min
Above Casing 200mm Min
Below Casing 130mm Min
Front (For Servicing) 500mm Min
Front (In Operation) 5mm Min
0 10203040
20
40
60
80
100
120
140
160
180
200
220
Water Flow Rate (litres/min)
Pressure Drop (mbar)
8
17
25
33
42
50
58
66
75
83
91
Pressure Drop (in wg)
Hydraulic Resistance Chart
Appliance Type C13 C33
Nox Class 5
Heat Output
(Condensing 40°C Mean Water Temp)
Max Min
15 HE kW 16.49 10.1
Btu/h 56,260 34,520
24 HE kW 23.8 10.1
81.200 34,520
Water Content
litres 2.6
pints 4.6
Static Head
max 30 metres (100 ft)
min 1 metre (3.25 ft)
Low Head 0.2m (8 in) min
System Detail
fully pumped open vented & sealed systems
Gas Connection
RC1/2(1/2in BSPT)
Controls
installer preset boiler thermostat, safety
thermostat, flow switch, electronic flame
sensing,temperature protection thermostat
& condensate blockage sensor
The efficiency is
Promax 15 HE - 91.3%
Promax 24 HE - 91.0%
This value is used in the UK Government’s
Standard Assessment Procedure (SAP) for
energy rating of dwellings. The test data from
which it has been calculated has been
certified by 0086.
SEDBUK Declaration For
Potterton Promax 15 HE & 24 HE

9
5.0 DIMENSIONS AND FIXINGS
Publication No. 5106451
DIMENSIONS
A600mm
B320mm
C390mm
D125mm ØMin.
E150mm
F125mm
SIDE FLUE (left and right)
For every 1m of horizontal flue
length, the clearance above the
top of the flue elbow should be
55mm to incorporate the 3°
(1 in 20) fall in the flue from the
terminal to the elbow.
The 3°(1 in 20) fall provided by
the elbow is to allow condensate
to run back to the boiler, for
disposal through the condensate
discharge pipe.
Flue length (Y)
up to 1m
1m - 2m
2m - 3m
Clearance (X)
55mm
110mm
165mm
360°Orientation
Tube Ø110mm
DC
B
A
E
F
Y
3°
(1 in 20)
X
3°
(1 in 20)
Fig. 6
Fig. 7

6.0 SYSTEM DETAILS
10 Publication No. 5106451
6.1 Water Circulating Systems
1. The appliance is suitable for use with open vent
fully pumped systems and sealed systems .
The following conditions should be observed on
all systems:
•The static head must not exceed 30m (100ft)
of water.
•The boiler must not be used with a direct
cylinder.
•Drain cocks should be fitted to all system low
points.
•All gas and water pipes and electrical wiring
must be installed in a way which would not
restrict the servicing of the boiler.
•Position isolating valves as close to circulating
pump as possible.
•It is recommended that the return pipe is fitted
with an automatic air vent as close to the boiler
as is practical.
NOTE: Full TRV Systems (refer to section 6.4)
Where all the radiators are controlled by TRV’s then
pump protection will be required. This can be done by
either of the options opposite (see Fig A & B). The
option shown in Fig. A should only be used on a
full TRV system without a bypass. Fig. B shows a
system with a bypass that must be capable of
allowing a flow of at least 3 l/min.
6.2 Treatment of Water Circulating
Systems
•All recirculatory water systems will be subject to
corrosion unless an appropriate water treatment
is applied. This means that the efficiency of
the system will deteriorate as corrosion sludge
accumulates within the system, risking damage
to pump and valves, boiler noise and circulation
problems.
•When upgrading existing systems that exhibit
evidence of sludging, it is advisable to clean the
system prior to treatment in order to remove any
sludge and reduce the likelihood of these
deposits damaging new components.
•When fitting new systems flux will be evident
within the system, which can lead to damage of
system components.
•All systems must be thoroughly drained and
flushed out. The recommended flushing and
cleansing agents are Betz-Dearborn Sentinel
X300 or X400 and Fernox Superfloc Universal
Cleanser which should be used following the
flushing agent manufacturer’s instructions.
•System additives - corrosion inhibitors and
flushing agents/descalers should be suitable for
aluminium and comply to BS7593 requirements.
The only system additives recommended are
Betz-Dearborn Sentinel X100 and Fernox-Copal
which should be used following the inhibitor
manufacturer’s instructions.
Failure to flush and add inhibitor to the system
will invalidate the appliance warranty.
•It is important to check the inhibitor
concentration after installation, system
modification and at every service in accordance
with the manufacturer’s instructions. (Test kits
are available from inhibitor stockists.)
•For information or advice regarding any of the
above contact the Technical Enquiries.
Boiler
No demand
for hot water
Central
heating
load
All TRV’s shut down
(boiler flow switch
causes pump to stop)
Live feed
to pump
Switch live from
programmer, etc.
S/L N P/F
Fig. A Wiring to the pump feed connection of boiler
Fig. B Providing a 3 l/min bypass
Boiler
No demand
for hot water
Central
heating
load
All TRV’s shut down
(pump continues
around bypass)
Switch live from
programmer,
room stat, etc.
S/L
junction
S/L N P/F 3 l/min
bypass
Boiler
Connections
Boiler
Connections
NOTE: This boiler does not require a bypass.
This boiler does not require a permanent live.
These diagrams only refer to pump protection for fully TRV’d systems.

11
6.0 SYSTEM DETAILS
Publication No. 5106451
6.3 Pipework
1. The sizes of flow and return pipes from the boiler
should be determined by normal methods, according
to the requirements of the system. The connection to
the boiler is 28mm (compression).
2. Due to space requirements within the boiler
outercase, pipework should comprise of solder
fittings.
3. A 20 °C (36°F) drop in temperature across the
system is recommended for condensing boilers.
Existing radiators may be oversized and so allow
this, but where radiator sizing is marginal it may be
advisable to retain a system temperature drop of
11°C (20°F).
4. In systems using non-metallic pipework it is
necessary to use copper pipe for the boiler Flow and
Return. The copper must extend at least 1 metre
from the boiler and include any branches (Fig. 7a).
6.4 System Controls
1. For optimum operating conditions, the heating
system into which the boiler is installed should
include a control system.
2. Such a system will comprise of a timer control and
separate room or cylinder thermostats as
appropriate.
3. The boiler should be controlled so that it operates
on demand only.
4. Operation of the system under control of the
preset boiler thermostat & TRV’s only does not
produce the best results.
6.5 Low Head Installation
1. Using a close couple arrangement the minimum
head is as shown in the diagrams (Figs. 8 & 9)
subject to the following conditions:
a) The pump being adjusted to give an 20oC
drop across the boiler.
b) The pump must be fitted on the flow.
c) The pump must be fitted in accordance with
the pump manufacturer's instructions.
d) The open vent pipe must be taken up from a
tee in a horizontal section of the flow pipe.
An alternative Low Head Installation (Fig. 10)
2. For heads below 400mm then a combined vent
and feed pipe may be connected. This must be a
minimum of 22mm diameter. It is recommended that
an air separator is fitted when using a combined feed
and vent pipe.
6.6 Thermal Stores
1. The Promax 15 & 24 HE is suitable for fitting with
a Thermal Store, for details please contact Technical
Enquires (08706 049 049).
Typical Low Head Installation
If Conditions Require,
This System Possible
Alternative Low Head Installation
Boiler
500mm
45°
22mm
Open Vent
1000mm
Min
150mm
Max
15mm
Cold
Feed
400mm
Min Head
Return
Pump
Flow
Boiler
500mm
45°
22mm
Open Vent
400mm
Min Head
1000mm
Min
Automatic
Air Vent 15mm
Cold
Feed
150mm
Max
Return
Pump
Flow
Return
Pump
Flow
Boiler
200mm
Min
Air
Separator
22mm
Feed & Vent
Pipe
Fig. 8
Fig. 9
Fig. 10
Boiler
Flow
Return
Copper
0.5m
Copper
1m
Copper
0.5m
Fig. 7a

6.0 SYSTEM DETAILS
12 Publication No. 5106451
6.7 Sealed Systems (Fig. 11)
1. SAFETY VALVE - A safety valve complying with
the requirements of BS 6750 Part 1 must be fitted
close to the boiler on the flow pipe by means of a
horizontal or vertically upward connection with no
intervening valve or restrictions and should be
positioned to facilitate testing. The valve should be
pre-set and non-adjustable to operate at a pressure
of 3 bar (45 Ibf/in2). It must be arranged to discharge
any water or steam through a pipe to a safe outlet
position.
2. PRESSURE GAUGE - A pressure gauge of
minimum range 0-4 bar (0-60 Ibf/in2) with a fill
pressure indicator must be fitted to the system,
preferably at the same point as the expansion vessel
in an easily visible position.
3. EXPANSION VESSEL - An expansion vessel
complying with the requirements of BS 4814 must be
fitted to the system by means of a connection close
to the inlet side of the circulating pump in accordance
with the manufacturers instructions, the connecting
pipe being unrestricted and not less than 15mm (1/2
in) nominal size. The volume of the vessel should be
suitable for the system water content and the
nitrogen or air charge pressure should not be less
than the system static head (See Table. 1).
Further details of sealed system design can be
obtained from BS 5449 and the British Gas
publication entitled 'Specifications for Domestic Wet
Central Heating Systems'.
4. FILLING POINT - A filling point connection on the
central heating return pipework must be provided to
facilitate initial filling and pressurising and also any
subsequent water loss replacement / refilling.
The sealed primary circuits may be filled or
replenished by means of a temporary connection
between the primary circuit and a supply pipe
provided a ‘Listed’double check valve or some other
no less effective backflow prevention device is
permanently connected at the inlet to the circuit and
the temporary connection is removed after use.
The filling method adopted must be in accordance
with all relevant water supply regulations and use
approved equipment.
Your attention is drawn to, for GB: Guidance G24.2
and recommendation R24.2 of the Water Regulations
Guide. for IE: the current edition of I.S. 813
“Domestic Gas Installations”.
5. MAKE UP SYSTEM - A method of replacing water
lost from the system should be provided either by
means of a make up vessel of not more than 3 litres
(5 pints) capacity, mounted above the highest point of
the system, or by re-pressurisation of the system.
6. VENTING - A method of venting the system during
filling and commissioning must be provided by fitting
automatic air vents or by venting manually.
7. HOT WATER STORAGE - The hot water storage
vessel must be of the indirect coil type. All
components used in the system must be suitable for
operation at 110°C (230°F) and at the pressure
allowed by the safety valve.
Initial System
Pressure (Bar)
Vessel Charge
Pressure (Bar)
Multiply Total
Water Content Of
System By (Litres)
0.067
0.112
0.207
0.441
0.087
0.152
0.330
0.125
0.265
0.5
1.0
1.5
2.0
1.0
1.5
2.0
1.5
2.0
0.5
1.0
1.5
Example :-
Then :-
System Volume = 75 litres
Vessel Charge Pressure = 1.0 bar
Initial System Pressure = 1.5 bar
75 x 0.152 = 11.4 litres
Expansion Vessel Volume
Method of determining minimum
value of expansion vessel volume for
sealed systems using Baxi Boilers
NOTE
Where a vessel of the calculated size is not obtainable
then the next available larger size should be used.
Safety
Valve
Pressure
Gauge
Pump
Filling
Point
Air
Vent
3 Litre
Top Up Bottle
(if required)
Radiator
Circuit
Expansion
Vessel
System Drains
at Low Point
Max Boiler Flow
Temp = 82°C
Boiler
Fig. 11
Table. 1
Stop
Valve
Double
Check
Valve
DHW
Mains
Inlet
CH
Return
Temporary
Hose
Stop
Valve
Fig. 11a

13
7.0 SITE REQUIREMENTS
Publication No. 5106451
7.1 Location
1. The boiler may be fitted to any suitable wall with
the flue passing through an outside wall or roof and
discharging to atmosphere in a position permitting
satisfactory removal of combustion products and
providing an adequate air supply. The boiler should
be fitted within the building unless otherwise
protected by a suitable enclosure i.e. garage or
outhouse. (The boiler may be fitted inside a cupboard
- see Section 7.2).
2. If the boiler is sited in an unheated enclosure then
it is recommended to incorporate an appropriate
device for frost protection in the system controls.
3. If the boiler is fitted in a room containing a bath or
shower, it can only be fitted in zone 3, (Figs. A & B
shows zone dimensions for a bathtub. For other
examples refer to Section 601 of the Current I.E.E.
Wiring Regulations) reference must be made to the
relevant requirements.
In GB this is the current I.E.E. Wiring Regulations
and Building Regulations.
In IE reference should be made to the current edition
of I.S. 813 “Domestic Gas Installations”and the
current ETCI rules.
4. If the boiler is to be fitted into a building of timber
frame construction then reference must be made to
the current edition of Institute of Gas Engineers
Publication IGE/UP/7 (Gas Installations in Timber
Framed Housing).
7.2 Ventilation of Compartments
1. Where the boiler is installed in a cupboard or
compartment, no air vents are required for cooling
purposes providing that the minimum dimensions
below are maintained.
Sides 15mm
Top 200mm
Bottom 130mm
Front 30mm
2. If the boiler is installed in a smaller cupboard or
compartment it must be ventilated according to BS
5440 Part 2 and the minimum clearances given in
section 4.0 “Technical Data”maintained.
3. Any compartment should be large enough to
house the boiler only.
NOTE: The ventilation label on the front of the outer
case MUST NOT BE REMOVED when the
appliance is installed in a compartment or
cupboard.
Zone 2
Zone 1
Zone 0
Zone 2
Zone 3
Zone 3
Zone 2
Window
Recess
Window
Recess
0.6 m 2.4 m
Ceiling
Outside
Zones
Outside Zones
Zone 3
Zone 3
Zone 2
Zone 2
Zone 1
Zone 0
2.25 m
Zone 2
Window
Recess
3.0 m
2.4 m
0.6 m
Fig. A
Fig. B
In GB Only
In GB Only

7.0 SITE REQUIREMENTS
14 Publication No. 5106451
7.3 Clearances (Figs. 12 &13)
1. A flat vertical area is required for the installation of
the boiler.
2. These dimensions include the necessary
clearances around the boiler for case removal,
spanner access and air movement. Additional
clearances may be required for the passage of pipes
around local obstructions such as joists running
parallel to the front face of the boiler.
3. For unventilated compartments see Section 7.2.
7.4 Gas Supply
1. The gas installation should be in accordance with
the relevant standards. In GB this is BS 6891. In IE
this is the current edition of I.S. 813 “Domestic Gas
Installations”.
2. The connection to the appliance is a 1/2in BSPT
internal threaded connection located at the rear of
the gas service cock.
3. Ensure that the pipework from the meter to the
appliance is of adequate size.
Do not use pipes of a smaller diameter than the
boiler gas connection.
7.5 Electrical Supply
1. External wiring must be correctly earthed,
polarised and in accordance with relevant
regulations/rules. In GB this is the current I.E.E.
Wiring Regulations. In IE reference should be made
to the current edition of ETCI rules.
2. The mains supply is 230V ~ 50Hz fused at 3A.
NOTE: The method of connection to the
electricity supply must facilitate complete
electrical isolation of the appliance. Connection
may be via a fused double-pole isolator with a
contact separation of at least 3mm in all poles
and servicing the boiler and system controls only.
130mm
600mm
390mm
200mm
5mm Min
5mm Min
5mm
500mm
For Servicing
Purposes
Fig. 12
Fig. 13 In Operation
3°
(1 in 20)
320mm

15
7.0 SITE REQUIREMENTS
Publication No. 5106451
7.6 Condensate Drain
FAILURE TO INSTALL THE CONDENSATE
DISCHARGE PIPEWORK CORRECTLY WILL AFFECT
THE RELIABLE OPERATION OF THE BOILER
The condensate discharge pipe MUST NOT RISE at
any point along its length. There MUST be a fall of AT
LEAST 2.5°(50mm per metre) along the entire run.
NOTE: It is unnecessary to fit an air break in the
discharge pipe.
1. The condensate outlet terminates in a 1”BSP nut
and seal for the connection of 21.5mm (3/4in) plastic
overflow pipe which should generally discharge
internally into the household drainage system. If this is
not possible, discharge into an outside drain is
acceptable.
2. Ensure the discharge of condensate complies with
any national or local regulations in force.
BS 6798:2000 & Part H1 of the Building Regulations
give further guidance.
3. The discharge pipe should be run in a proprietary
drain pipe material e.g. PVC, PVC-U, ABS, PVC-C or
PP.
4. Metal pipework is NOT suitable for use in
condensate discharge systems.
5. The pipe should be a minimum of 21.5mm diameter
and must be supported using suitably spaced clips to
prevent sagging.
6. Any pipe fitted externally must be kept as short as
possible to minimise the potential of freezing.
7. Any condensate discharge pipework external to the
building (or in an unheated part of it e.g. garage) must
be insulated to protect against frost. It is also
recommended that the pipe diameter is increased to
32mm.
8. If the boiler is fitted in an unheated location the entire
condensate discharge pipe should be treated as an
external run.
9. In all cases discharge pipe must be installed to aid
disposal of the condensate. To reduce the risk of
condensate being trapped, as few bends and fittings as
possible should be used.
10. When discharging condensate into a soil stack or
waste pipe the effects of existing plumbing must be
considered. If soil pipes or waste pipes are subjected to
internal pressure fluctuations when WC's are flushed or
sinks emptied then back-pressure may force water out
of the boiler trap and cause appliance lockout.
Examples are shown of the following methods of
termination:-
i) to an internal soil & vent pipe
ii) via an internal discharge branch (e.g. sink waste)
iii) to a drain or gully
iv) to a purpose made soakaway
Boiler
2.5°Minimum fall
Termination to an internal soil
and vent pipe
450mm min
Boiler
2.5°Minimum fall
External termination via internal
discharge branch
e.g sink waste - downstream
Sink
Pipe must terminate
above water level but
below surrounding
surface
Boiler Pipe must terminate
above water level but
below surrounding
surface
2.5°Minimum fall
Termination to a drain or gully
Boiler
500mm min
2.5°Minimum fall
Termination to a purpose made
soak-away
Holes in the soak-away
must face away from the
building
50mm per metre of pipe run
50mm per metre of pipe run
50mm per metre of pipe run
50mm per metre of pipe run

7.0 SITE REQUIREMENTS
16 Publication No. 5106451
N
I
I
G
F
M
I
AAF
H
J,K
D
E
H
Likely flue positions requiring
a flue terminal guard
C
RA
I
J,K
I
L
S
B
7.7 Flue
NOTE: Due to the nature of the boiler a plume of
water vapour will be discharged from the flue. This
should be taken into account when siting the flue
terminal.
1. The following guidelines indicate the general
requirements for siting balanced flue terminals.
For GB recommendations are given in BS 5440 Pt.1.
For IE recommendations are given in the current
edition of I.S. 813 “Domestic Gas Installations”.
2. If the terminal discharges onto a pathway or
passageway, check that combustion products will not
cause a nuisance and that the terminal will not
obstruct the passageway.
3. Take into consideration the effect the plume of
vapour may have on neighbours when siting the flue.
4. Adjacent surfaces close to the flue terminal may
need protection from the effects of condensation.
Alternatively a flue deflector kit (part no. 248167) is
available.
5. For installation of the flue into an internal corner at
the 25mm dimension the flue deflector kit (part no.
248167) must be fitted.
6. * Reduction to the boundary is possible down to
25mm but the flue deflector kit (part no. 248167) must
be fitted.
7. If required a suitable terminal guard is available
from Potterton for use with the flue deflector.
8. For fitting under low soffits and eaves it is
acceptable for the flue to project up to 500mm from
the face of the wall to the inside of the air intake. This
can be painted if required using a suitable external
paint.
9. If a terminal is less than 2 metres (783/4in) above a
balcony, above ground or above a flat roof to which
people have access, then a suitable terminal guard
must be provided.
Fig. 17
Fig. 16
300 min
Terminal
Assembly
Top View Rear Flue
Property Boundary Line
NOTE: The distance from a fanned draught appliance
terminal installed parallel to a boundary may not be less
than 300mm in accordance with the diagram below
Table. 2
Terminal Position with Minimum Distance (Fig. 17) (mm)
AaDirectly below an opening, air brick, opening
windows, etc. 300
BaAbove an opening, air brick, opening window etc. 300
CaHorizontally to an opening, air brick, opening window etc. 300
D Below gutters, soil pipes or drain pipes. 25
E Below eaves. 25
F Below balconies or car port roof. 25
G From a vertical drain pipe or soil pipe. 25
H From an internal (i) or external (ii) corner. (i) 25 (ii) 115
I Above ground, roof or balcony level. 300
J From a surface or boundary line facing a terminal. 600
K From a terminal facing a terminal (Horizontal flue). 1200
From a terminal facing a terminal (Vertical flue). 600
L From an opening in carport (e.g. door, window)
into the dwelling. 1200
M Vertically from a terminal on the same wall. 1500
N Horizontally from a terminal on the same wall. 300
R From adjacent wall to flue (vertical only). 300
S From an adjacent opening window (vertical only). 1000
aIn addition, the terminal should be no nearer than 150 mm to an
opening in the building fabric formed for the purpose of accommodating
a built-in element such as a window frame. See BS 5440 Pt. 1.
*

17
7.0 SITE REQUIREMENTS
Publication No. 5106451
7.8 Flue Dimensions
See Section 2.2. The standard horizontal flue kit
allows for flue lengths between 270mm (105/8”) and
800mm (32”) from elbow to terminal
(Fig. 18).
The maximum permissible equivalent flue length
is: 4 metres (Fig. 18a).
NOTE: Each additional 45°of flue bend will
account for an equivalent flue length of 0.5m.
eg. 45°= 0.5m, 90°= 2 x 45°= 1m etc.
7.9 Terminal Guard (Fig. 19)
1. When codes of practice dictate the use of terminal
guards, they can be obtained from most Plumbers’
and Builders’Merchants.
2. There must be a clearance of at least 50mm
between any part of the terminal and the guard.
3. When ordering a terminal guard, quote the
appliance name and model number.
4. The flue terminal guard should be positioned
centrally over the terminal and fixed as illustrated.
7.10 Vertical Flue
1. Only a flue approved with the Potterton Promax 15
HE & 24 HE can be used.
2. For information on vertical flues consult the
Potterton Flue Guide Brochure or Guidance Notes
supplied with the vertical flue pack.
Fig. 18
Fig. 18a
Pictorial examples of flue runs where EQUIVALENT flue length equals 4m
Fig. 19
270mm 800mm
0.5m
1m
0.5m
0.5m

7.0 SITE REQUIREMENTS
18 Publication No. 5106451
Key Accessory Size Baxi Code
Number
Concentric Flue System 110mm diameter
A Horizontal flue kit 850mm 236921
B Straight extension kit 1000mm 241695
500mm 241694
250mm 241692
C Bend kit 93°241687
D Bend kit (pair) 45°241689
E Horizontal flue terminal 243013BAX
Clamp 110mm 243014BAX
Twin Flue System 80mm diameter
F Straight extension kit 1000mm 238690
500mm 238692
250mm 238694
G Bend kit 90°246139
H Bend kit (pair) 45°246138
Universal Vertical Flue Kits
J Twin flue adaptor kit 242757
K Vertical flue terminal 242802
L Universal roof tile 25°/50°243015
M Roof cover plate kit 243131
N Flat roof flashing 243016BAX
R Boiler vertical flue adaptor 5106888
Clamp 80mm 238684
7.11 Flue options
Concentric
The maximum equivalent lengths are 4m (horizontal)
or (vertical). These lengths exclude the standard
elbow and flue/terminal assembly (horizontal) and
terminal assembly (vertical).
Twin Flue
The total maximum equivalent flue length is 150m.
NOTE: Each 1m of flue duct should be calculated as
2m.
Any additional “in line”bends in the flue system must
be taken into consideration. Their equivalent lengths
are:
Concentric Pipes: 45°bend 0.5 m
93°bend 1.0 m
Twin Flue Pipe: 45°bend (air duct) 1.3 m
45°bend (flue duct) 2.6 m
90°bend (air duct) 4.8 m
90°bend (flue duct) 9.6 m
Detailed examples of equivalent flue length
calculation are given in the Installation Guidance
Notes for each flue system type.
(Documents 243501 and 243502 for concentric and
twin pipe respectively).
A - Standard Flue
D
E
B
C
K
L
D
M
J
F
J
N
HG
R

19
8.0 INSTALLATION
Publication No. 5106451
Check Site Requirements (section 7.0) before
commencing.
8.1 Initial Preparation
The gas supply, gas type and pressure must be
checked for suitability before connection (see
Section 7.4).
NOTE: If the boiler wall plate is to be pre-hung,
follow both these instructions and those on the
boiler pack.
1. Remove the fixing template (Fig. 20) from the
carton.
2. After considering the site requirements
(see Section 7.0) position the template on the wall
ensuring it is level both horizontally and vertically.
3. Mark the position of the centre hole for the wall
plate (Fig. 20).
4. Mark the centre of the flue hole (rear exit).
For side exit: project the horizontal side flue center
line into the corner of the room and along the wall to
where the flue hole will be drilled (Fig. 20).
The diagram (Fig. 21) shows the dimensions
required to ensure any horizontal flue is installed
with the correct fall to the boiler. Mark the offset (V)
dimension and if required, mark the position of the
gas and water pipes. Remove the template.
5. Cut the hole for the flue (minimum diameter
125mm, see table for wall thicknesses and flue
diameters).
6. Drill and plug the wall as previously marked.
Secure the wall plate using the centre hole.
7. Ensuring the wall plate is level both horizontally
and vertically, drill and plug at least 4 securing
positions at the top and bottom through the wall
plate. Utilising the slots available ensure the wall
plate is square and secure to the wall (Fig. 22).
8. Loosely route the condensate discharge pipe to
the lower left hand side of the wall plate.
Fig. 22
Wall Plate
Centralising
Screw
Wall Thickness
up to 227mm
up to 750mm
up to 1200mm
Flue Hole ø
125mm core drill
150mm core drill
175mm core drill
Fig. 20
Fig. 21
Horizontal
Side Flue
Centre Line
EXAMPLE: Boiler is 2 metres
away from corner of wall, flue
duct hole is 60mm up from
horizontal side flue centre line.
This will maintain the approx 3°
backfall to the boiler.
Wall Plate Template
Edge of Boiler
0.5
1.0
2.0
3.0
4.0
Distance in metres from boiler to the wall.
For pipe lengths greater than 4m increase the off-set by 52mm
for every additional metre to maintain approx 3°inclination.
V
Flue Duct Hole
Offset V (mm) 27 55 110 165 220
(metres)
(mm)
3°
Backfall to the Boiler, ie. 2m flue offset (V) position 110mm
Example
2m
Example
V = 110mm
125mm
Centre
Hole

8.0 INSTALLATION
20 Publication No. 5106451
8.2 Preparing The Boiler
1. Remove the outer carton.
2. Remove the internal packaging.
3. Lift the outercase upwards and remove
(Fig. 23).
Potterton declare that no substances harmful
to health are contained in the appliance or
used during appliance manufacture.
Outercase
Fig. 23