Potterton Promax HE Store 90 Litres Release note

© Baxi Heating UK Ltd 2006
About the Boiler See page 4 for models covered by these instructions.
This is a Floor Mounted Fan Assisted Balanced Flue Gas Boiler.
This boiler is for use with Natural Gas (G20) only at 20 mbar and for use in GB/IE only.
About Safety The Gas Safety (Installation and Use) Regulations.
‘‘ 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 the Installation & Service Instructions and the rules in
force.
Read these Instructions before installing or lighting the boiler
These Instructions include the Benchmark Commissioning Checklist and should be left
with the user for safe keeping.
Installation & Servicing Instructions Promax HE Store
Condensing Boilers with
Integrated Hot Water Storage
Promax Store

2© Baxi Heating UK Ltd 2006
Building Regulations and the Benchmark
Commissioning Checklist
Building Regulations (England & Wales) require
notification of the installation of a heating appliance to
the relevant Local Authority Building Control
Department. From 1 April 2005 this can be achieved via
a Competent Persons Self Certification Scheme as an
option to notifying the Local Authority directly. Similar
arrangements will follow for Scotland and will apply in
Northern Ireland from 1 January 2006.
CORGI operate a Self Certification Scheme for gas
heating appliances.
These arrangements represent a change from the
situation whereby compliance with Building Regulations
was accepted as being demonstrated by completion of
the Benchmark Logbook (which was then left on site
with the customer).
With the introduction of Self Certification Schemes, the
Benchmark Logbook is being withdrawn. However, a
similar document in the form of a commissioning
checklist and service interval record is incorporated at
the back of these instructions.
This company is a member of the Benchmark initiative
and fully supports the aims of the programme. Its aim is
to improve the standards of installation and
commissioning of central heating systems in the UK and
to encourage the regular servicing of all central heating
systems to ensure safety and efficiency.
Building Regulations require that installations should
comply with manufacturer's instructions. It is therefore
important that the commissioning checklist is completed
by the installer. The relevant section of Building
Regulations only relates to dwellings. Therefore the
checklist only applies if the appliance is being installed
in a dwelling or some related structure.
The flowchart opposite gives guidance for installers on
the process necessary to ensure compliance with
Building Regulations.
© Baxi Heating UK Ltd 2006 All rights reserved. No part of this
publication may be reproduced or transmitted in any form or by any
means, or stored in any retrieval system of any nature (including in any
database), in each case whether electronic, mechanical, recording or
otherwise, without the prior written permission of the copyright owner,
except for permitted fair dealing under Copyrights, Designs and Patents
Act 1988.
Applications for the copyright owner’s permission to reproduce or make
other use of any part of this publication should be made, giving details of
the proposed use, to the following address:
The Company Secretary, Baxi Heating UK Ltd, Pentagon House,
Sir Frank Whittle Road, Derby, DE21 4XA.
Full acknowledgement of author and source must be given.
WARNING: Any person who does any unauthorised act in relation to a
copyright work may be liable to criminal prosecution and civil claims for
damages.
Natural Gas
Potterton HE Store
G.C.No41 601 24 (90 litre)
G.C.No41 591 76 (115 litre)
G.C.No41 591 77 (150 litre)

3
© Baxi Heating UK Ltd 2006
Choose Building
Regulations Notification
Route
Contact your relevant Local
Authority Building Control
(LABC) who will arrange
an inspection or contact
a government approved
inspector
LABC will record the data
and will issue a
certificate of compliance
CORGI will record the data and
will send a certificate of
compliance to the property
You must ensure that the
notification number issued by
CORGI is written onto the
Benchmark Checklist
Scheme Members only
Call CORGI on: 0870 88 88 777
or log onto:
www.corgi-notify.com
within 10 days
If you notify via CORGI Scheme,
CORGI will then notify the
relevant Local Authority
Building Control Scheme
on member's behalf
Complete the
Benchmark Checklist
Install and Commission this
appliance to manufacturer's
instructions
Competent Person's
Self Certification Scheme
Building Control
Complete the
Benchmark Checklist
Install and Commission this
appliance to manufacturer's
instructions
Installer Notification Guidelines

4© Baxi Heating UK Ltd 2006
Contents
Panel Removal.....................................................
Technical Data......................................................
Introduction..........................................................
Health & Safety Information......................................
Codes of Practice......................................................
Storage, Unpacking and Handling............................
1. Installation Requirements..............................
1.1 Gas Supply......................................................
1.2 Electricity Supply.............................................
1.3 Location of Boiler..........................................
1.4 Compartment Installation &
Ventilation..................................................
1.5 Flue Systems..................................................
1.6 Water Supply & Systems..............................
1.7 Discharge Pipework......................................
2. Installation...................................................
2.1 Install the Boiler.............................................
2.2 Connect the Flue System.............................
2.3 Connect the Gas Supply...............................
2.4 Connect the Condensate Pipe ........................
2.5 Connect the Water Supply .....................
2.6 Connect the Power Supply Cable..................
2.7 Optional Immersion Heater...........................
2.8 How to Drain Hot Water Storage Cylinder.....
2.9 Control Panel, Display & Diagnostics............
3. Commissioning............................................
3.1 Commission the Boiler..................................
3.2 Hand Over to the User...................................
4. Service & Replacement of Parts..................
4.1 General Access............................................
4.2 Automatic Air Vent........................................
4.3 Expansion Vessel/Pump...............................
4.4 Pressure Sensor/Pressure Relief Valve......
4.5 Air/Gas Valve/Injector/Fan.............................
4.6 Spark Generator/Ignition Electrode...............
4.7 Burner..........................................................
4.8 Boiler Control Assembly................................
4.9 Diverter Valve Actuator..................................
4.10 Overheat Thermostat...................................
4.11 Diverter Valve Complete, Manual Air Vent and
Temperature Flow, Return & Dry
Fire Sensors.................................................
4.12 Heat Exchanger............................................
4.13 Immersion Heater and Immersion Heater
Combined Thermostat/Thermal Cut Out.......
Gas/Air Valve Setup Procedure.........................
5. Wiring Diagrams............................................
6. Fault Finding..................................................
Diagnostic Codes..........................................
7. Short List of Spares.......................................
The models covered by these instructions are:-
Promax HE Store G.C. No.
90 Litres 41 601 24
115 Litres 41 591 76
150 Litres 41 591 77
Important
Refer to Page 8 for Storage, Unpacking and Handling
Instructions.
Benchmark Commissioning Checklist
Potterton is a member of the Benchmark initiative and
fully supports the aims of the programme. Benchmark
has been introduced to improve the standards of
installation and commissioning of central heating
systems in the UK and to encourage the regular
servicing of all central heating systems to ensure safety
and efficiency.
Important – Failure to install and commission this
appliance to manufacturer’s instructions may invalidate
the warranty. This note does not affect your statutory
rights.
CORGI
All CORGI registered installers carry a CORGI
identification card and have a registration number. Both
should be recorded in your Benchmark Checklist.
You can check your installer is registered by telephoning
[phone] or writing to:-
CORGI. 1 Elmwood, Chineham Business Park,
Crockford Lane, Basingstoke, RG24 8WG.
Safety, Performance & Quality
Promax HE Store boilers have been assessed by a
Government appointed Notified Body and shown to meet
the 'Essential Requirements' of the European Gas
Appliance Directive 90/396/EEC.
The Directive lays down requirements for the safety and
efficiency of the appliance, together with its design,
construction, and use of materials.
It also requires the production process to be covered by
an approved and monitored system of quality assurance.
Warning - The addition of anything that may interfere
with the normal operation of the appliance without
explicit 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.
TM

5
© Baxi Heating UK Ltd 2006
Panel Removal
MAX0006B
Bottom Section
Union Nuts
(remain with
Bottom Section)
DHW Sensor Pocket
(310mm deep)
Top & Bottom Section
Handholds
(Underneath boiler)
Lifting and
plumbing
access
each side
Mains power
supply and
Immersion Heater
cable entry holes
Pull up and away Top Panel
2
4
3
Pull forward Front Panel at the bottom and lift off
General AccessPlumbing Access
1
Pull forward Bottom Panel
Unscrew Upper Panel at the bottom and pull away
Retaining Screws (Upper Panel)
Condensate
outlet hole
Top Section
Lift Heat Engine onto
Cylinder. Ensure the
rollers engage into
location channels.
Tilt and slide until front
location pegs drop into
position on the cylinder.
Location Peg
Location Channel
Rollers
Fig. 1
Important: Refer to Page 8 for Storage, Unpacking and Handling Instructions.

6© Baxi Heating UK Ltd 2006
Technical Data
Unless indicated, data shown relevant to all models 90 litre 115 litre 150 litre
Classifications Appliance category CAT I2H
Flue Type C13 - C33 - C53 (as supplied)
NOx Class 5 (< 70 mg/kWh)
Cylinder Insulation CFC, HCFC = 0%
Input (hot water/central heating) - gross 7.8 - 27.4 kW
Output to CH (non-condensing) 6.8 - 24.0 kW
Output to CH (condensing) 7.6 - 25.9 kW
Inlet pressure 20 mbar
Gas rate (after 10 mins.) 2.6 m3/hr max.
Gas control differential (offset) -3 Pa to - 8 Pa (- 0.03 to - 0.08 mbar)
CO (average) 70 ppm
Ventilation Requirements: No Compartment Ventilation Required
Connections CH Flow & Return 22 mm ‘Techtite’/compression
DHW Inlet & Outlet 22 mm tube end
Gas 22 mm compression
Temperature/Press. Relief Valve 22 mm compression from tundish.
Condensate Outlet Flexible Pipe 500 mm long (fits 21.5 mm PP overflow systems)
Inlet Control Group 22 mm compression inlet & outlet
Set reduced pressure 2.5 bar, expansion relief valve set 8.0 bar
Filling Loop 15 mm /1/2” union (accessible behind lower front panel)
Secondary Expansion Vessel 12 litre, pre-charge 2.5 - 2.7 bar (supplied separately)
Automatic bypass Built in
Pressure loss warning Gauge on facia
Built in programmer 2-channel, pre-programmed, battery back-up, separate times for HW
& CH, advance button, CH off selector
External programmer
Built-in room thermostat Dedicated connectors on user terminal block
Built in frost protection Boiler protected below 5 °C
Optional Immersion Heater Heatrae ‘Mega’. 3 kW at 240V, Advantica Approved
Electricity supply 230v ~ 3A fused supply,
Power Consumption (maximum) 166 Watts (Grundfos pump) 156 Watts (Wilo pump)
Working pressures Primary 0.9 - 2.5 bar
DHW 1.0 - 2.5 bar
Mains Supply 1.0 - 16.0 bar
Pressure Relief Valve (Primary) 3.0 bar
Temperature/Press. Relief Valve Pre-set 95 °C, 10.0 bar opening
DHW temperature 30 °C to 60 °C
DHW flow rate (Practical maximum assuming suitable mains supply) 25 l/m max. 25 l/m max. 25 l/m max.
Weights Lift Weight Heat Engine 45 kg
Cylinder 37 kg 41 kg 49 kg
Full Weight 171 kg 202 kg 246 kg

7
© Baxi Heating UK Ltd 2006
MAX0007A
Note:
At these minimum clearances above
the appliance, adequate working
access MUST be provided.
Note:
Cupboard
intended
to provide
access.
Removable Top Panel
Typical Cupboard Installation
with twin vertical air/flue pipes
Typical Bulkhead Installation
with rearwards horizontal concentric flue
250
min
Removable Top Panel 450
min
250
min 650 max
Door
Frame
400 mm
Recommended
*
*
*400 mm
Recommended
*
Concentric
Flue
Ø80
Air
Tube
No
Clearance
required
Ø80
Flue
Tube
145
145
Side Flue
Rear Flue
(300 min.)
All dimensions
in mm
600
Twin
Flue
MAX0008B
Ø100 Air Tube
&
Ø60 Flue Tube
C/L
Inner Wall
Outer Wall
Inner Wall
Outer Wall
C/L
550
Fig. 2
Fig. 3
Promax Store
Promax Store
PromaxStore
1544 mm
150 Litre
Model
115 Litre
Model
90 Litre
Model
1344 mm
1264 mm
25 mm 25 mm
25 mm
25 mm
25 mm
25 mm

8© Baxi Heating UK Ltd 2006
Introduction
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".
Read the instructions fully before installing or lighting the
boiler.
Promax HE Store is a floor standing condensing
combination boiler which incorporates a hot water store to
provide domestic hot water (DHW) and central heating
(CH). The DHW temperature is user adjustable (e.g. for
summer/winter operation). Operation is automatic and the
fully modulating pre-mixed burner ensures that gas is
burned cleanly and efficiently within the condensing heat
exchanger. An advanced burner control includes flame
monitoring, pressure monitoring and other safety features,
plus status and diagnostic displays which are large and
easy to read.
Installation of this boiler as an unvented hot water system
falls within the scope of the Building Regulations 1995 (Part
G). These require that installation of an ‘unvented’ system
shall be notified to the local authority Building Control
Department; also that the work must be carried out by a
competent person as defined in the Approved Document
G3. The above requirements do not apply if hot water is
obtained via an open vented feed tank.
Samples of the Promax HE Store gas boilers have been
examined by DVGW Technologies Limited, a EU Notified
Body. The range is certified to comply with the essential
requirements of the Gas Appliance Directive 90/396/EEC,
the Low Voltage Directive 72/23/EEC and shows
compliance with the Electro Magnetic Compatibility
Directive 89/336/EEC, the Boiler Efficiency Directive
92/42/EEC and are therefore permitted to carry the CE
Mark.
Operation
The boiler control works on the principle of “hot water
priority” so the central heating output may be
temporarily delayed if the hot water temperature
drops below the selected temperature e.g. after
drawing a hot bath. The selected temperature is user
adjustable in the range 45° to 65 °C
To suit conventional radiator based central heating
systems, the boiler will normally provide a flow
temperature of around 80 °C. The boiler control
automatically responds to lower central heating loads
by reducing the boiler output (which saves wasteful
on-off cycling).
This boiler must be installed into a sealed
(pressurised) primary system.
Provision is made for fitting both room and frost
thermostats if required. Note: The boiler has its own
in-built frost protection which will seek to prevent the
boiler temperature dropping below 5 °C
For summer operation the user can switch off the
central heating at the control panel.
Visible Pluming
The efficient condensing operation of Promax HE
Store will naturally cause condensate to form in the
flue pipe and pluming of the condensing gases will be
visible during all but the most favourable atmospheric
conditions. In installations with long flue runs, some
condensate may be discharged from the terminal.
The flue terminal must, therefore, be sited to avoid
nuisance from either phenomenon.
Delivery & Kits Available
Promax HE Store boilers are delivered in three
packages (1) the heat engine and unvented accessory
kit, (2) the hot water cylinder and (3) the flue kit. The
flue kit must be ordered/specified additionally to the
boiler.
Health and Safety Information for the Installer
and Service Engineer
Under the Consumer Protection Act 1987 and Section
6 of the Health and Safety at Work Act 1974, we are
required to provide information on substances
hazardous to health.
This boiler does not contain substances harmful to
health; it does not contain asbestos. Small quantities of
adhesives and sealants used in the product are cured
and present no known hazards.

9
© Baxi Heating UK Ltd 2006
Condensate
Trap
3 Way
Diverter Valve
Flow Sensor
Combustion
Analyser
Test Point Flue Air
Automatic
Bypass
Primary Expansion Vessel
Automatic
Air Vent
Gas
Valve
Isolation Valve
Isolation
Valve
Pump
Primary
Relief
Valve
Heat Exchanger
Combination Valve
Tundish
Cross/Check
Valve
Tundish
Gas
Gas Cock
D.H.W. Sensor
Hot Water
Cylinder
CH
Return
CH
Flow
Schematic Diagram
Filling Loop
Double
Check
Valve
DHW
Cold Main
Stopcock
Balanced Cold
Feed to Shower
Pressure Relief Valve
Secondary
Expansion
Vessel
Fan
AB
T.P.R.V.
Codes of Practice
The appliance is suitable only for installation in GB and IE
and should be installed in accordance with the rules in
force.
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 Codes 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.
Fig. 4
In GB the following Codes of Practice apply:
Standard Scope
BS6891 Specification for low pressure gas pipework
in domestic premises.
BS5440 Pt.1 Specification for installation of flues.
BS5440 Pt.2 Specification for installation of ventilation for
gas appliances (except that compartment
ventilation is amended in section 8 of these
instructions).
BS5546 Specification for installation of gas hot water
supplies.
BS5449 Specification for forced circulation hot water
central heating systems.
BS6798 Specification for installation of gas fired hot
water boilers of rated input not exceeding
70kW.
In IE:
I.S. 813 Domestic Gas Installations.
The following BS standards give valuable additional information:
BS6891 Specification for low pressure gas pipework
in domestic premises.
BS5546 Specification for installation of gas hot water
supplies.
BS5449 Specification for forced circulation hot water
central heating systems.

10 © Baxi Heating UK Ltd 2006
1. Installation Requirements
Storage, Unpacking & Handling
This boiler is delivered in two sections for safety and
ease of handling. Store both the Top (heat engine) and
the Bottom (cylinder) under cover in dry conditions.
Remove the Promax HE Store unvented Accessory Kit
from above the heat engine to reduce lift weight. (The
front and top panels can also be removed if required -
see Fig. 1).
Handholds are provided at the top rear of the heat
engine and will assist with removing it from the transport
tray. Handholds are provided at both sides and
underneath the cylinder.
Use a handling device e.g. sack truck, to manually
move either section over long distances. Trucking must
be done from the rear. Take particular care to avoid
damaging outer panels or programmer.
These items should be lifted and handled by two
people. Stooping should be avoided and protective
clothing worn when necessary. Carrying and lifting
equipment should be used as required for moving Top
and Bottom to where they will be assembled and
installed..
Determine beforehand whether the Top and Bottom
should be assembled to enable the complete unit to be
moved into position, or whether to fit the cylinder and
then lift the heat engine into position.
The Top has 2 downward facing dowel pins which
provide accurate location on to the cylinder. Take care
to avoid trapping hands and fingers during assembly.
Take great care when manoeuvring the boiler into its
final location and avoid twisting movements of the body.
Do not attempt to carry the complete boiler as the
Top is only dowelled to the Bottom.
Dispose of packaging in accordance with environmental
guidelines.
1.1 Gas Supply
Entry holes are provided in the base and via knockouts
in the side panels.
This boiler requires a natural gas supply of 2.6 cubic
metres per hour. A 22 mm gas inlet connection is
provided at the front and gas supply pipework of not
less than 22 mm diameter should be run to the boiler.
The meter and supply pipes must be capable of
delivering this quantity of gas in addition to the demand
from any other appliances in the house and must be
governed at the meter.
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".
The whole of the gas installation must be checked for
soundness and purged in accordance with, in GB, BS
6891 and in IE, I.S. 813 “Domestic Gas Installations”.
1.2 Electricity Supply
The boiler requires a 230V ~ 50Hz single-phase 3A fused
electrical supply. 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 the ETCI rules.
Detailed wiring instructions are given in Section 10.
Power consumption is approximately 90 - 166 W.
WARNING: THIS BOILER MUST BE EARTHED
In the event of an electrical fault after installation of the
boiler, preliminary electrical systems checks must be
carried out i.e. Earth Continuity, Short Circuit, Polarity and
Resistance to Earth.
1.3 Location of Boiler
The boiler must not be sited outside or in any outhouse
where it could be exposed to the weather.
The boiler must be installed on a flat floor capable of
supporting the weight of the unit when full of water – up
to 250 kg for the 150 litre model.
It should be sited to minimise the length of flue and to
avoid long hot water pipe runs.
The extended flueing capability enables the boiler to be
sited well away from an outside wall, thus installation in
a first floor cupboard or compartment, basement, utility
room or kitchen are all feasible locations.
The location chosen must permit the provision of a
satisfactory external flue termination. The location must
also provide adequate space for servicing and air
circulation.

VENTILATION
1. Where the appliance is installed in a cupboard or
compartment, no air vents are required.
2. BS 5440: Part 2 refers to room sealed appliances
installed in compartments. The appliance will run
sufficiently cool without ventilation.
1.5 Flueing
This is a “room sealed” condensing boiler. Flue systems
are supplied in kits, or components can be ordered
individually from Potterton. Only Promax HE Store flue
components (which are designed for condensing
operation) can be used.
Flue Systems
All boilers are supplied to accept either the concentric
horizontal flue system or the Promax 80 mm dia. twin
flue system, however several flue system options are
available.
Each system is room sealed and offers a choice of flue
type and termination method, (page 13).
• Concentric balanced flue with horizontal terminal
• Twin flue with vertical terminal *
Flue extension lengths and bends should be
purchased separately, as required.
* These terminals must be ordered/specified separately.
11
© Baxi Heating UK Ltd 2006
If floor settlement is likely due to the weight of the boiler,
ensure that both the flueing and pipework layouts safely
provide sufficient flexibility.
If the boiler is to be fitted in a room containing a bath or
shower 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.
1.4 Compartment Installation and
Ventilation
General guidance for cupboard/compartment
installations, including airing cupboards, is contained in
BS 6798. Specific requirements for Promax HE Store
are given below.
1. The compartment should be a fixed rigid structure
large enough to allow it and the boiler to be
inspected and serviced. A minimum width between
the door jambs of 570 mm must be provided.
2. Minimum clearances are indicated in Fig.3. A full
height compartment door must be at least 15 mm
from the front of the boiler and provide 200 mm
access height above the boiler.
3. Householders should be discouraged from storing
clothes etc. on the boiler itself. A removable shelf at
least 75 mm above the boiler is acceptable.
4. The internal surfaces of an understairs cupboard
must be lined with non-combustible materials. The
door shall have a BS 476 fire resistance of not less
than 0.5 hour.

12 © Baxi Heating UK Ltd 2006
General Requirements for Horizontal Flue
Terminations
Detailed recommendations for flueing are given in
BS5440: Part 1. The following notes give general
guidance. The horizontal balanced flue terminal must be
installed so that it is exposed to external air, preferably
on a clear expanse of wall. Acceptable positions are
indicated in Fig. 3. Avoid positions where the terminal is
adjacent to projections; particularly immediately under a
balcony, inside a re-entrant position, or immediately
adjacent to a drain pipe. If the boiler is fitted under a
ventilator or opening window, the terminal must be at
least 300 mm from any part of the window or ventilator
and in accordance with BS5440: Part 1.
The flue pipe must not be closer than 25 mm to
combustible material. Additional clearance must be
provided when passing the flue through timber walls.
Advice on gas installations in timber framed buildings is
contained in IGE technical publication IGE/UP/7
available from the Institution of Gas Engineers, 21
Portland Place, London W1N 3AF.
Guidance notes for Flue Installation
Read these Installation Instructions before installing
the boiler. Before starting an installation, check that the
correct flue kit has been supplied with the boiler.
Detailed recommendations for flue installations are given
in BS 5440:1: 2000. The following notes are for general
guidance only.
a) The flue system must be constructed using only
Promax approved components.
b) It is important that the position of the terminal allows
free passage of air across it at all times.
c) It is ESSENTIAL TO ENSURE that products of
combustion discharging from the terminal cannot re-
enter the building, or any other adjacent building,
through ventilators, windows, doors, other sources of
natural air infiltration, or forced ventilation / air
conditioning.
d) The minimum acceptable dimensions from the flue
terminal to obstructions and ventilation openings are
specified in Figs. 2 & 3 of these instructions.
e) If the flue terminal discharges into a pathway or
passageway check that combustion products will not
cause nuisance and that the terminal will not obstruct
the passageway.
f) Where terminals are fitted within 850 mm of a plastic
or painted gutter, or 450 mm of painted eaves, an
aluminium shield at least 750 mm long must be fitted
to the underside of the plastic or painted surface.
g) Where installation will be in an unusual location,
special procedures may be necessary. BS 6798 gives
detailed guidance on this aspect.
h) As the Promax Store is a condensing boiler the flue
duct must have a fall back to the boiler of nominally 3°.
j) The efficient condensing operation of the Promax
HE Store will naturally give rise to condensation in the
flue gases and pluming will occur in all but the most
favourable atmospheric conditions. Some
condensate may also be discharged from the terminal.
The terminal must, therefore, be sited to avoid
nuisance from either phenomenon.
k) Where the lowest part of the terminal is less than 2 m
above the level of any ground, balcony, flat roof or
place to which people have access, the terminal must
be protected by a guard of durable material.
1m Min
to
15m Max
120mm Min
apart
S
S
1m Min
to
15m Max
600mm Min
apart
Mini Terminal
(sited in loft)
U
T
V
V

13
© Baxi Heating UK Ltd 2006
Flue Options
1. The Potterton Store can be fitted with flue
systems as illustrated.
2. The standard flue kit, Part No. 5118489
comprises a concentric 100/60 terminal and a
93° bend. It is suitable only for horizontal
termination applications.
3. Maximum permissible equivalent flue
lengths are:-
Horizontal Concentric 10 metres
Vertical Concentric 10 metres
Vertical Twin Pipe 15 metres
4. Any additional “in line” bends in the flue
system must be taken into consideration.
Their equivalent lengths are:-
Concentric Pipes:
45° bend 0.5 metres
93° bend 1.0 metres
Twin Flue Pipe
45° bend 0.25 metres
91.5° bend 0.50 metres
The elbow attached to the boiler is not
included in any equivalent length calculations
5. The illustrations opposite show examples of
permissible flue systems.
6. Instructions for guidance and fitting are
included in each kit, where appropriate.
NOTE: Flue length is measured from point
Y to Z as shown.
Horizontal
Flues
Vertical
Flues
Vertical
Flues
(Twin Pipe)
Z
Y
Z
Y
Z
Y
Key Accessory Size Code No
Concentric Flue System 100mm diameter
A Horizontal flue kit 5118489
B Straight extension kit 1000mm 5111074
C Bend kit 93° 5111075
D Bend kit 45° 5111076
D Bend kit (pair) 45° 5111085
Clamp 100mm 5111080
Flue Terminal Deflector 60mm 5111068
Wall Liner 5111067
R Vertical Roof Terminal 5118576
Twin Flue System 80mm diameter
E Straight extension kit (pair) 1000mm 5111087
F Bend kit (pair) 90° 5111072
G Bend kit (pair) 45° 5111086
H Twin flue adaptor kit 5111079
J Twin vertical adaptor kit 5111084
Clamp (pair) 80mm 5111081
S Twin Flue Termination kit 5120172
V Single 80mm Ø Terminal 5121792
U Adaptor 60/80 5121791
T Pitched Roof Terminal 25°/45° 5106164
Universal Vertical Flue Kits
K Vertical flue terminal 5111078
L Universal roof tile 25°/45° 246141
M Universal roof tile 35°/55° 246142
N Roof cover plate kit 246143
O Flat roof flashing 246144
P Concentric Vertical adaptor 5111070
Q Plume Displacement Kit 5118638
A
B
C
Plume Displacement Kit 60 /100 Ø
1M Extensions, 45° & 93° bends are
also available - see the literature
supplied with the kit for details
Q
F
G
J
E
H
L,M
N
P
K

14 © Baxi Heating UK Ltd 2006
N
I
I
G
F
M
I
AAF
H
J,K
D
E
H
Likely flue positions requiring a flue terminal guard
C
R
A
I
J,K
I
L
T
S
B
Top View
Top
View
Concentric
Terminal
Assembly
Rear
Concentric
Flue
Side Concentric
Flue
300 min. 300 min.
MAX0027A
Property
Boundary Line
Fig. 6
AaDirectly below an opening, air brick,
opening windows, etc.
BaAbove an opening, air brick, opening window, etc.
CaHorizontally to an opening, air brick,
opening window, etc.
DBelow gutters, soil pipes or drain pipes.
EBelow eaves.
FBelow balconies or car port roof.
GFrom a vertical drain pipe or soil pipe.
HFrom an internal or external corner.
IAbove ground, roof or balcony level.
JFrom a surface facing a terminal.
KFrom a terminal facing the terminal.
LFrom an opening in a
carport (e.g. door, window)
into the dwelling.
MVertically from a terminal on the same wall.
NHorizontally from a terminal on the same wall.
RFrom adjacent wall to flue (vertical only).
SFrom an adjacent opening window (vertical only).
TBelow eaves or balcony (vertical only).
Terminal Position with Minimum Distance (mm)
For IE, refer to I.S. 813 "Domestic Gas Installation".
Fanned Draught Balanced Flue
Note: The distance from a fanned draught appliance terminal installed
parallel to a boundary may not be less than 300 mm in accordance with
the diagram on the left.
300
300
300
25*
25*
25*
25*
25*
300
600
1200
1200
1500
300
300
1000
600
aIn addition, the terminal should not be 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.
Opening
Window or Door
100mm
MIN.
IMPORTANT: If fitting a Plume
Displacement Flue Kit, the air inlet
must be a minimum of 100mm
from any opening windows or
doors
Plume
Displacement Kit
Air Inlet
IMPORTANT:
• Only ONE 25mm* clearance is allowed per installation.
• Under car ports we recommend the use of the plume
displacement kit.
• The terminal position must ensure the safe and
nuisance - free dispersal of combustion products.

15
© Baxi Heating UK Ltd 2006
1.6 Water Supply
Mains Supply Requirements
It is essential that the mains supply pressure and
available flow rate are capable of meeting demand for
both hot and cold water Promax Store is not
recommended for unvented use where the dynamic
mains pressure is below 1.0 bar.
Unless consistently high mains pressures are available,
it is unlikely that a service pipe of less than 25 mm OD
(Blue MDPE) will supply an adequate flow rate.
Plumbing Design
A combination inlet valve group is included with every
Promax Store (packed in the “Accessories” box
supplied with the Heat Engine). The mains water supply
must be connected via the combination reducing valve
and the cross fitting, in that order. Both components are
clearly marked with the direction of flow (see Fig. 11
page 21).
The cold feed pipe to showers (and other mixer fittings
needing balanced pressures) must be taken from the
22mm blanked outlet port of the combination reducing
valve (or a tee between this and the cross fitting). The
valve can be sited near where the water mains enters
the dwelling, to assist with providing reduced pressure
to all the system.
Cold water draw-offs that do not require a balanced
supply e.g. hose-union or WC cistern, should be teed
off upstream of the combination reducing valve.
A 22mm connection is provided from the hot water
store. Smaller diameter pipework may be used locally
for terminal fittings as part of a balanced design.
Thermostatic shower mixers are recommended to
optimise performance; these must be suitable for use at
mains pressure. Using flow restricyors will help prolong
the showering time available from smaller capacity
stores.
Use in Hard Water Areas
In the UK., water is drawn from diverse sources some
of which have high levels of natural hardness. If not
dealt with effectively, the scaling associated with hard
waters can adversly affect hot water performance. As a
general guide, if the temporary hardness exceeds 200
mg/l, then some form of water treatment device is
required. The ultimate solution is an ion-exchange (salt
regenerated) water softener. In addition to protecting
the Promax heat exchanger against the effects of
limescale, an ion-exchange softener offers users other
benefits and should be specified with an appropriate
flow rate capacity.
Water “conditioning” devices such as those which dose
the incoming water with food grade polyphosphates
can be effective in reducing limescale but require correct
siting and regular replenishment to remain operational.
They should generally not be fitted where heat could
impair their perfomance. Other types of device can
inhibit scale formation but their effectiveness may vary.
The manufacturers of any water conditioning device
should be consulted regarding its suitability for the
application and the particular water supply to the
installation address.
Record the type of conditioner being used in
“Benchmark” Commissioning Checklist.
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 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.
Using, for example Betz-Dearborn Sentinel X300 or
X400 or Fernox Superfloc Universal Cleanser. They
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, e.g 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.)
Sealed Primary Systems
This boiler must be installed into a sealed primary
system. As a general guide systems of up to 7-9
radiators will operate satisfactorily with the 10 litre
expansion vessel built into the boiler.
•Guidance on expansion vessel sizing
These notes explain how to calculate the total
expansion vessel volume required, based on the size
and the initial cold fill pressure of the system. If the
required volume exceeds that of the vessel fitted to
the boiler then an additional vessel should be
installed, on the return connection from the heating
system. The charge pressure of any additional vessel
is assumed to be 1.0 bar, the same as the vessel fitted
to the boiler.

16 © Baxi Heating UK Ltd 2006
If the initial cold fill pressure is 1.0 bar:
expansion vessel size = 0.11 x system volume
This fill pressure will allow the maximum expansion
capacity, though any minor loss of water will result in
a rapid pressure drop. An additional expansion vessel
is only required if the total system volume exceeds
98 litres.
This includes the 4 litre primary circuit volume
within the Promax HE Store boiler - thus radiator and
pipework volume should not exceed 94 litres.
Pipework above boiler
Air vents must be fitted at the highest positions on flow
and return pipes and at any point where air is likely to
collect.
TRV’s in System
An automatic bypass valve is built into the boiler to
allow thermostatic radiator valves to be fitted. This can
be switched into or out of circuit as required.
1.7 Discharge Pipework
It is a requirement of Building Regulation G3 that any
discharge from an unvented system is conveyed to
where it is visible, but will not cause danger to persons
in or about the building. The tundish and discharge
pipes should be fitted in accordance with the
requirements and guidance notes of Building
Regulation G3. The G3 Requirements and Guidance
section 3.9 are reproduced in the following sections.
Information Sheet No. 33 available from the British
Board of Agrement gives further advice on discharge
pipe installation. For discharge pipe arrangements not
covered by G3 Guidance or BBA Info Sheet No.33
advice should be sought from either your local Building
Control Officer or Potterton.
G3 Requirement “...there shall be precautions ... to
ensure that the hot water discharged from safety
devices is safely conveyed to where it is visible but will
not cause danger to persons in or about the building.”
G3 Guidance SECTION 3.9
The discharge pipe (D1) from the vessel up to and
including the tundish is generally supplied by the
manufacturer of the hot water storage system. Where
otherwise, the installation should include the discharge
pipe(s) (D1) from the safety device(s). In either case the
tundish should be vertical, located in the same space
as the unvented hot water storage system and be fitted
as close as possible and within 500 mm of the safety
device e.g. the temperature relief valve. Note: The
tundish is factory fitted during manufacture of the
Promax HE Store. The discharge pipe (D2) from the
tundish should terminate in a safe place where there is
no risk to persons in the vicinity of the discharge,
preferably be of metal and:
a.be at least one pipe size larger than the nominal
outlet size of the safety device unless its total
equivalent hydraulic resistance exceeds that of a
straight pipe 9m long i.e. discharge pipes between 9m
and 18m equivalent resistance length should be at
least two sizes larger than the nominal Outlet size of
the safety device, between 18 and 27m at least 3 sizes
larger, and so on. Bends must be taken into account in
calculating the flow resistance. Refer to Fig. 7, Table 1
and the worked example.
An alternative approach for sizing discharge pipes
would be to follow BS 6700:1987 Specification for
design installation, testing and maintenance of
services supplying water for domestic use within
buildings and their curtilages. Appendix E. section E2
and table 21.
b.have a vertical section of pipe at least 300 mm long,
below the tundish before any elbows or bends in the
pipework.
c. be installed with a continuous fall.
d.have discharges visible at both the tundish and the
final point of discharge, but where this is not possible
or practical, there should be clear visibility at one or
other of these locations. Examples of acceptable
discharge arrangements are:
i. ideally below a fixed grating and above the water
seal in a trapped gully.
ii. downward discharges at low level; i.e. up to
100mm above external surfaces such as car
parks, hard standings, grassed areas etc. are
acceptable providing that where children may
play or otherwise come into contact with
discharges a wire cage or similar guard is
positioned to prevent contact, whilst maintaining
visibility.
iii. discharges at high level; e.g. into a metal hopper
and metal down pipe with the end of the
discharge pipe clearly visible (tundish visible or
not) or onto a roof capable of withstanding high
temperature discharges of water and 3m from
any plastic guttering system that would collect
such discharges (tundish visible).
iv. where a single pipe serves a number of
discharges, such as in blocks of flats, the number
served should be limited to not more than 6
systems so that any installation discharging can
be traced reasonably easily. The single common
discharge pipe should be at least one pipe size
larger than the largest individual discharge pipe
(D2) to be connected. If unvented hot water
storage systems are installed where discharges

17
© Baxi Heating UK Ltd 2006
Typical Discharge Pipe Arrangement
Condensate Trap
500 mm
Flexible Tube
supplied
Metal discharge pipe from
Tundish with continuous fall
Fixed
Grate
Discharge
above
Fixed
Grate
Trapped Gulley
Internal
S.V.P.
21.5 mm
PVC
Overflow
Pipework
Tundish
T.P.R. Valve
300mm min.
450mm min.
MAX0011A
Promax Store
Fig. 7
Valve Minimum Minimum Maximum Resistance
outlet dischage discharge resistance created by
size pipe D1 pipe D2 allowed, each elbow
from expressed or bend
tundish as a length
of straight
pipe (i.e. no
elbows or
bends)
22 mm up to 9 m 0.8 m
G1/2 15 mm 28 mm up to 18 m 1.0 m
35 mm up to 27 m 1.4 m
28 mm up to 9 m 1.0 m
G3/4 22 mm 35 mm up to 18 m 1.4 m
42 mm up to 27 m 1.7 m
35 mm up to 9 m 1.4 m
G1 28 mm 42 mm up to 18 m 1.7 m
54 mm up to 27 m 2.4 m
Table 1. Sizing of copper discharge pipe (D2) for common temperature
relief valve outlet sizes. Note: shaded area is reproduced for
completeness but does not apply to this boiler.
from safety devices may not be apparent i.e.
in dwellings occupied by blind, infirm or
disabled people, consideration should be
given to the installation of an electronically
operated device to warn when discharge
takes place.
Note: The discharge will consist of scalding
water and steam. Asphalt, roofing felt and
non-metallic rainwater goods may be
damaged by such discharges.
Worked example of discharge pipe sizing
The example below is for a G1/2 temperature
relief valve with a discharge pipe (D2) having 4
No. elbows and length of 7 m from the tundish to
the point of discharge.
From Table 1:
Maximum resistance allowed for a straight length
of 22mm copper discharge pipe (D2) from a G1/2
temperature relief valve is 9.0 m.
Subtract the resistance for 4 No. 22 mm elbows
at 0.8m each = 3.2 m.
Therefore the permitted length equates to: 5.8 m.
5.8 m is less than the actual length of 7 m
therefore calculate the next largest size.
Maximum resistance allowed for a straight length
of 28 mm pipe (D2) from a G1/2 temperature
relief valves equates to 18 m.
Subtract the resistance of 4 No. 28 mm elbows at
1.0 m each - 4.0 m.
Therefore the maximum permitted length equates
to: 14 m.
As the actual length is 7 m, a 28 mm min. (D2)
copper pipe will be satisfactory.
Warnings
• Under No circumstances should the factory
fitted Temperature/Pressure Relief Valve be
removed other than by Authorised Potterton
personnel. To do so will invalidate any
warranty or claim.
• The cold water Inlet Control Group must be
fitted to the mains water supply to the
Promax HE Store when it is operated as an
unvented system.
• Control and safety valves MUST NOT be
tampered with.
• The discharge pipe MUST NOT be blocked
or used for any other purpose.
• The tundish must not be removed but can be
sited outside the RH panel using the opening
provided.
• Electrical components must not be sited near
the tundish.

18 © Baxi Heating UK Ltd 2006
MAX0021B
Outline of base plate
Outline of front panels
Double arrows are from rear of boiler
70 43 119 122 35 60 54
512
514
536
560
572
544
507
DHW
TPRV
Discharge
Cold
Feed
Gas
Condensate
39
567
Dimensions are approximate
All pipes are 22mm
C/H Flow
Alternate
C/H Flow or
Condensate
Outline of insulation
46
C/H Return
550 Overall
600 overall
2. Installation
2.1 Install the boiler
Before starting an installation, check that the correct flue
kit and correct capacity cylinder have been supplied.
Important: When soldering plumbing fittings, do not
allow flame from blowtorch to come into contact with
the insulating foam or other non-metallic parts.
Guidance on where to locate the boiler is given in
Sections 1.3 and 1.5.
In some instances it will be
advantageous to pre-plumb pipework or to pre-fix
terminal, air/flue pipes and duct
.
1. Remove top and front panels (see Fig. 1) and
carefully set aside.
2. Determine boiler final position. The cutaway in the
cylinder base allows pipework to be brought up from
below floor level. Use the dimensions below or the
template on the reverse of the Installation Guide to
pre-drill any holes. Pipes must not obstruct service
access to the immersion heater (if fitted) or to the
condensate trap.
3. Move boiler into position. The need to move as Top
and Bottom sections or as a complete assembly will
depend on the individual installation. The Top has 4
downward facing dowel pins which provide accurate
location on to the cylinder. Take care to avoid trapping
hands and fingers during assembly.
4. Apply sealant to cone faces of both 22mm Union
Nuts (see Fig. 10). Remove cardboard pipework
support. Attach the 15mm x 90° branch pipe joining the
two relief valves/tundish.
5. Release DHW temperature sensor and un-roll cable.
Route cable behind cylinder pipes and push sensor
fully home (approx. 310mm - 12”) into the pocket in
the cylinder.
6. Remove small knock-outs as required either side of
casing for plumbing access. The handholds in the side
panels can also be used. Further access holes allow
the condensate to be routed via the LH panel and the
DHW to be plumbed via the RH panel.
2.2 Connect the Flue System
1. Unless already fitted, install the flue system as shown
in the Installation Instructions supplied with the flue kit.
2.3 Connect the Gas Supply
1. Ensure that the gas supply is isolated.
2. The gas connection to the boiler is 22 mm.
Refer to Section 1.1 for information on the required gas
supply.
Do not turn the gas supply on at this stage.
Fig. 9
MAX0023C
22mm Gas
Connection
-
+
PROG
SEL
PROG
SEL
-
C.H.ADVANCE
H.W.TEMP
RESETBURNER LOCKOUT
MAINSON
POWER
+
RWC
Gas
Cock
(0pen)
Fig. 8

RWC
Cable Bushing
Gas Cock
Isolating Valve
Condensate Trap
Condensate Outlet
(500mm supplied)
Plumbing
'NO GO' Area
Immersion
Heater
Domestic Hot
Water Sensor
D.H.W. Outlet
D.H.W.
Outlet
Pressure Relief Valve (3 bar)
TPR Valve (Temperature
& Pressure Relief)
By-pass Valve
Isolating Valve
Tundish
Discharge Pipe
Pressure Gauge
Pipework shown as this
NOT SUPPLIED
Filling Loop
Potterton Promax Store
150 litre model shown
Mains Cold Inlet
CH Return
Gas Inlet
CH Flow
MAX0002D
22mm Union Nuts
15mm Branch Pipe
Promax Store
Display
Selector & Reset Switch
CH Control Knob
DHW Control
PCB Enclosure
Gas Valve
Diverter Valve
Manual Air Vent
Flue Outlet
Programmer
Pressure Gauge
Pump
Expansion Vessel
Fan
Flue Sample Point
19
© Baxi Heating UK Ltd 2006
Fig. 10
Component & Connection Identification

20 © Baxi Heating UK Ltd 2006
2.4 Condensate Drain Pipe
Before fitting, fill the condensate trap with water.
Fit the steady bracket (with round hole) for the condensate
trap to the lower pair of holes in the left hand cylinder side
panel. Snap the C-shaped bracket into the groove in the
condensate connector. Insert the condensate trap into the
steady bracket and fit the C-shaped bracket to the upper
pair of holes in the left hand cylinder side panel.
Ensure that the washer seal is in place as indicated and
tighten the large nut.
The condensate pipe should be run in 21.5/22.0 mm
diameter plastic material suitable for operation at 60° C.
Solvent weld PVC overflow is recommended or a PP
system can be used. Copper tube must not be used. Do
not use push-fit plastic pipe.
Use the flexible pipe provided to connect to 21.5mm PVC
pipe; alternatively a Marley or Plumb Center elbow can be
used to direct the condensate pipe through the LH side
panel (see Fig. 10a). When using the Osma PVC overflow
system, a 3/4 -to-22mm adaptor No. 158 may be required.
Internal pipework should have a bore diameter no smaller
than 14 mm.
External pipework should be kept to a minimum, and have
a bore diameter no smaller than 32 mm.
Ideally the condensate pipe should be run internally to the
house soil and vent stack or to a waste pipe. Alternatively,
the condensate may be discharged into the rainwater
system, or a purpose-built soakaway.
All connecting drainage pipework must have a fall of at
least 50 mm per metre run. It is recommended that the
pipe is insulated if run externally to minimise the effects of
freezing, and that a plastic insert is fitted that provides a
siphon/weir action to encourage the water to flow in
intermittent bursts rather than dripping continuously.
Note: Connection of a condensate pipe to a drain may be
subject to local building regulations.
Manual Air Vent
Using the manual air vent, thoroughly vent air from top
of the heat exchanger when filling the system to save
time during the boiler commissioning. Note: 1/4” dia.
manometer tube fits the manual vent.
Central Heating Pump & System By-pass
The central heating pump is factory fitted and an
automatic system by-pass is provided. The boiler can be
used in systems controlled by thermostatic radiator
valves (TRVs) but it is essential that the by-pass isolating
valve is fully open.
The circulating pressure and flowrate available for the
central heating system is shown opposite with the by-
pass in circuit.
MAX0022C
Promax Store
RWC
Fill up the Condensate
Trap with water, then
fit to the boiler
Condensate
Drain Pipe
500mm supplied
(suitable for 21.5mm
overflow pipe)
Washer Seal
Boiler
Condensate
Connection
Optional
Route -
DHW
Optional
Route -
Condensate
Lower Nut
Fig. 10a