Baxi Megaflo 2 System Compact GA Range Release note

© Baxi Heating UK Ltd 2013
Megaflo 2 System Compact GA
Range
Gas Fired Wall Mounted Condensing
System Boiler
Installation & Servicing Instructions
These instructions include the Benchmark Commissioning Checklist
and should be left with the user for safe keeping.

2© Baxi Heating UK Ltd 2013
Model Range
Baxi Megaflo 2 System 12 Compact GA
G.C.No 41-075-70
Baxi Megaflo 2 System 15 Compact GA
G.C.No 41-075-71
Baxi Megaflo 2 System 18 Compact GA
G.C.No41-075-72
Baxi Megaflo 2 System 24 Compact GA
G.C.No41-075-73
Baxi Megaflo 2 System 28 Compact GA
G.C.No41-075-74
Baxi Megaflo 2 System 32 Compact GA
G.C.No41-075-75
© Baxi Heating UK Ltd 2013 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 Limited,
Brooks House, Coventry Road, Warwick. CV34 4LL
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.
The Benchmark Scheme
Benchmark places responsibilities on both manufacturers and installers. The
purpose is to ensure that customers are provided with the correct equipment for
their needs, that it is installed, commissioned and serviced in accordance with the
manufacturer’s instructions by competent persons and that it meets the
requirements of the appropriate Building Regulations. The Benchmark Checklist
can be used to demonstrate compliance with Building Regulations and should be
provided to the customer for future reference.
Installers are required to carry out installation, commissioning and servicing work
in accordance with the Benchmark Code of Practice which is available from the
Heating and Howitzer Industry Council who manage and promote the Scheme.
Visit www.centralisation.co.UK for more information.
0086
ISO 9001
FLEM 00866
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.
The Health & Safety Executive operates the ‘Gas Safe Register’,
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.

3
Installer Notification Guidelines
© Baxi Heating UK Ltd 2013
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
‘Gas Safe Register’ will issue a
Building Regulations Compliance
Certificate to the property owner
and inform the relevant LABC
You must ensure that the
certificate number issued by
the ‘Gas Safe Register’ is written
onto the Benchmark Checklist
Scheme Members only
Call ‘Gas Safe Register’ on:
0800 408 5577
or log onto:
www.gassaferegister.co.uk
within 10 days
If you notify via the ‘Gas Safe
Register’, the register will issue
the Building Regulations
certificate on members’ 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

4
Legislation
© Baxi Heating UK Ltd 2013
Codes of Practice - refer to the most recent version
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 Gas Safe registered company
and holding current certificates in the relevant ACS modules, is deemed competent.
In IE, this must be carried out by a competent person as stated in I.S. 813 “Domestic
Gas Installations”.
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.
This company declares 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 Gas Safe
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 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.
BS EN 12828 Heating systems in buildings - Design for
water-based heating systems
BS EN 12831 Heating systems in buildings - Method for
calculation of the design heat load
BS EN 14336 Heating systems in buildings - Installation and
commissioning of water-based heating systems
In IE the following Codes of Practice apply:
Standard Scope
I.S. 813 Domestic Gas Installations.
The following standards give valuable additional information;
BS 5546 Installation of hot water supplies for domestic
purposes.
BS 7074 Expansion vessels and ancillary equipment for
sealed water systems.
BS 7593 Treatment of water in domestic hot water
central heating systems.
BS EN 12828 Heating systems in buildings - Design for
water-based heating systems
BS EN 12831 Heating systems in buildings - Method for
calculation of the design heat load
BS EN 14336 Heating systems in buildings - Installation and
commissioning of water-based heating systems
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 0085.
Product/Production certified by:
Notified Bodies 0085 & 0086.
For GB/IE only.
All Gas Safe registered engineers carry an ID card with their licence number and a
photograph. You can check your engineer is registered by telephoning
0800 408 5500 or online at www.gasgaferegister.co.uk

5
Safe Manual Handling
© Baxi Heating UK Ltd 2013
General
The following advice should be adhered to, from when first handling the boiler to the final stages of installation, and also during maintenance.
Most injuries as a result of inappropriate handling and lifting are to the back, but all other parts of the body are vulnerable, particularly shoulders, arms and hands.
Health & Safety is the responsibility of EVERYONE.
There is no ‘safe’ limit for one man - each person has different capabilities. The boiler should be handled and lifted by TWO PEOPLE.
Do not handle or lift unless you feel physically able.
Wear appropriate Personal Protection Equipment e.g. protective gloves, safety footwear etc.
Preparation
Co-ordinate movements - know where, and when, you are both going.
Minimise the number of times needed to move the boiler - plan ahead.
Always ensure when handling or lifting the route is clear and unobstructed. If possible avoid steps, wet or slippery surfaces, unlit areas etc. and take special care
on ladders/into lofts.
Technique
When handling or lifting always use safe techniques - keep your back straight, bend your knees. Don’t twist - move your feet, avoid bending forwards and
sideways and keep the load as close to your body as possible.
Where possible transport the boiler using a sack truck or other suitable trolley.
Always grip the boiler firmly, and before lifting feel where the weight is concentrated to establish the centre of gravity, repositioning yourself as necessary. See the
‘Installation’ section of these instructions for recommended lift points.
Remember
The circumstances of each installation are different. Always asses the risks associated with handling and lifting according to the individual conditions.
If at any time when installing the boiler you feel that you may have injured yourself STOP !!
DO NOT ‘work through’ the pain - you may cause further injury.
IF IN ANY DOUBT DO NOT HANDLE OR LIFT THE BOILER - OBTAIN ADVICE OR ASSISTANCE BEFORE PROCEEDING !!

6© Baxi Heating UK Ltd 2013
CONTENTS
1.0 Introduction 7
2.0 General Layout 8
3.0 Appliance Operation 9
4.0 Technical Data 10
5.0 Dimensions and Fixings 11
6.0 System Details 12
7.0 Site Requirements 14
8.0 Flue 20
9.0 Installation 22
10.0 Commissioning 27
11.0 Completion & System Draining 29
12.0 Servicing 30
13.0 Changing Components 32
14.0 Combustion & Calibration 39
15.0 Electrical 40
16.0 Short Parts List 41
17.0 Fault Finding 42
18.0 32 kW Model Supplement 47
Benchmark Checklist 50
Section Page

7
1.0 Introduction
© Baxi Heating UK Ltd 2013
1.1 Description
1. The Baxi Megaflo 2 System Compact GA Range are fully
automatic gas fired wall mounted condensing system boilers.
They are room sealed and fan assisted.
2. The boiler is set to give a maximum output of :-
12 models - 12 kW
12.7 kW (Condensing)
15 models - 15 kW
15.9 kW (Condensing)
18 models - 18 kW
19 kW (Condensing)
24 models - 24 kW
25.4 kW (Condensing)
28 models - 28 kW
29.6 kW (Condensing)
32 models - 32 kW
33.8 kW (Condensing)
3. The boiler is factory set for use on Natural Gas (G20). It can
be adapted to operate on Propane (G31) - see Section 10.1
‘Gas Type Check’.
4. The boiler incorporates a circulating pump and expansion
vessel. It is suitable for use only on fully pumped sealed
systems.
5. The boiler data badge gives details of the model, serial
number and Gas Council number and is situated on the
control box. It is visible when the case front panel is removed
(Fig. 2).
6. The boiler model name and serial number are also shown
on the information label behind the boiler control flap (Fig. 1).
This is for user reference.
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 one of the standard horizontal
telescopic flue kits detailed in the Flue Installation Guide.
9. All systems must be thoroughly flushed and treated with
inhibitor (see section 6.1).
1.2 Optional Extras
Various timers, external controls, etc. are available as optional
extras. Full details are contained in the relevant sales
literature.
1.3 Contents of Pack
The pack contains:-
• Boiler
• Wall Plate (including taps)
• Template
• Literature Pack
Fig. 1
Data Badge
Fig. 2
NOTE: These Installation & Servicing Instructions MUST be
read in conjunction with the Flue Installation Guide
supplied in the Literature Pack.
Control Flap
Information Label
Gas Type Label
The 12 to 28 kW models in the Baxi Megaflo 2
System Compact GA Range are of the same
dimensions and layout.The 32 kW model differs
in several respects - these are detailed in
Section 18.0 ‘32 kW Model Supplement’

8
2.0 General Layout
© Baxi Heating UK Ltd 2013
2.1 Layout 12 - 28 Models
1. Expansion Vessel
2. Expansion Vessel Locating Stud
3. Boiler Adaptor
4. Primary Heat Exchanger
5. Pump with Automatic Air Vent
6. Central Heating System Pressure Gauge
7. Fan Assembly
8. Flame Sensing Electrode
9. Air/Gas Collector
10. Spark Ignition Electrode
11. Combustion Box Cover & Burner
12. Condensate Trap
13. Safety Pressure Relief Valve
14. Boiler Control
15. Gas Valve
16. Boiler Drain Tap
17. Control Box Display
18. Heating Flow Sensor
19. Safety Thermostat
2
3
4
5
7
10
8
11
12
13
15
14
6
9
16
17
18
19
1

9
3.0 Appliance Operation
© Baxi Heating UK Ltd 2013
3.1 Operating Mode
1. With a demand for heating, the pump circulates water
through the primary circuit.
2. Once main burner ignites the fan speed controls the gas
rate to maintain the heating temperature measured by the
temperature sensor.
3. When the flow temperature exceeds the setting
temperature, a 3 minute delay occurs before the burner
relights automatically (anti-cycling). The pump continues to
run during this period.
4. When the demand is satisfied the burner is extinguished
and the pump continues to run for a period of 3 minutes
(Pump Overrun).
3.2 Boiler Frost Protection Mode
1. The frost protection mode is integral to the appliance and
functions as long as there is power to the boiler, as indicated
by the standby signal .
2. When the boiler temperature falls below 5°C the boiler
will fire until a temperature of 30°C is reached.
3. Further protection can be incorporated by using a system
frost thermostat.
3.3 Pump Protection
1. If the boiler has been inactive for a period of 24 hours the
pump will automatically operate for 1 minute to prevent
sticking.
Key
1. Pump with Automatic Air Vent
2. CH System Pressure Gauge
3. Central Heating Filter
4. Non-return valve
5. Hydraulic Pressure Sensor
6. Boiler Drain Tap
7. Pressure Relief Valve
8. Condensate Trap
9. Gas Valve
10. Safety Thermostat (105°C)
11. Heating Flow Sensor
12. Flue Sensor
13. Boiler Adaptor
14. Primary Heat Exchanger
15. Spark Ignition Electrode
16. Burner
17. Flame Sensing Electrode
18. Air/Gas Collector
19. Heating Return Sensor
20. Fan
21. Air-Gas Venturi
22. Expansion Vessel
Connections:-
A – Condensate Drain
B – Heating Flow
C – Gas Inlet
D – Heating Return
Fig. 3
1
2
3
4
5
6
7
8
9
10
11
12
13
15
18
14
16
17
19
20
21
22
ABCD

10
4.0 Technical Data
© Baxi Heating UK Ltd 2013
0
200 400 600 800 1000 1200
0.5
1
1.5
2
2.5
3
3.5
4
Metre (wg)
Flow Rate (l/h)
Pump - Available Head
0
5
5.5
6
4.5
4.1 (See Section 18.0 for 32 kW model)
Flue Terminal Diameter 100mm
Dimensions Projection 125mm
Outercase Dimensions
Casing Height - 700mm
Overall Height Inc Flue Elbow - 860mm
Casing Width - 390mm
Casing Depth - 300*mm
*This can be reduced to 290mm by removing the
boiler control access flap
Central Heating Primary Circuit
Pressures
bar
Safety Discharge 3
Max Operating 2.5
Min Operating 0.5
Recommended Operating Range 1-2
Pump
Available Head See graph below
Expansion Vessel - (For Central Heating only.
Integral with appliance)
bar
Min Pre-charge Pressure 0.5
(12, 15, 18, 24 & 28)
litre
Max Capacity of
CH System 100
Primary Water Content
of Boiler (unpressurised) 2.5
Connections copper tails
Gas Inlet - 22mm
Heating Flow - 22mm
Heating Return - 22mm
Pressure Relief Discharge - 15mm
Temperatures
C.H. Flow Temp (adjustable)
25°C to 80°C max (± 5°C)
NOxClass 5
Clearances
Above Casing 175 mm Min
Below Casing 150mm Min*
Front 450mm Min (For Servicing)
Front 5mm Min (In Operation)
L.H. Side 5mm Min
R.H. Side 5mm Min
*This is MINIMUM recommended dimension. Greater
clearance will aid installation and maintenance.
Electrical Supply 230V~ 50Hz
(Appliance must be connected to an
earthed supply)
Electrical Protection
IPX5D
Internal Fuse Rating F2L
Injector
12 model mm 3
15 model mm 3.3
18 model mm 3.6
24 model mm 4.6
28 model mm 4.9
Condensate Drain
To accept 21.5mm (3/4in) plastic waste pipe
External Fuse Rating 3A
Heat Input CH (Net) Max Min
12 model kW 12 2.1
15 model kW 15 2.2
18 model kW 18 2.6
24 model kW 24 3.5
28 model kW 28 4.1
Heat Output CH (Non-Condensing)
Max Min
12 model kW 12 2
15 model kW 15 2.1
18 model kW 18 2.5
24 model kW 24 3.4
28 model kW 28 4
Appliance Category CAT I 2H 3P
Appliance Type C13 C33 C43 C53
Heat Output CH (Condensing)
Max Min
12 model kW 12.7 2.2
15 model kW 15.9 2.3
18 model kW 19 2.8
24 model kW 25.4 3.7
28 model kW 29.6 4.3
Power Consumption
12 model W 110
15 model W 108
18 model W 125
24 model W 104
28 model W 135
Inlet Pressure (Natural Gas - G20)
mbar 20
Max Gas Rate (Natural Gas - G20)
(After 10 mins)
12 model m3/h 1.27
15 model m3/h 1.59
18 model m3/h 1.90
24 model m3/h 2.54
28 model m3/h 2.96
Inlet Pressure (Propane - G31)
mbar 37
NATURAL GAS ONLY !
PROPANE ONLY !
Max Gas Rate (Propane - G31)
(After 10 mins)
12 model kg/h 0.93
15 model kg/h 1.17
18 model kg/h 1.4
24 model kg/h 1.86
28 model kg/h 2.18
Weights
(12/15/18/24)
Packaged Boiler Carton 36.5kg
Installation Lift Weight 32.5kg
(28 model)
Packaged Boiler Carton 38.5kg
Installation Lift Weight 34.5kg
NOTE: All data in this section are nominal values
and subject to normal production tolerances.
SAP 2005 Seasonal Efficiency for N. G.
models is 91.1%
SAP 2005 Seasonal Efficiency for L.P.G.
models is 93.2%
SAP 2009 Annual Efficiency for N. G.
models is 89%
SAP 2009 Annual Efficiency for L.P.G.
models is 91%
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 0087.
SEDBUK Declaration
CO2N.G. 9.0% ± 0.7
L.P.G. 10.5% ± 1.0

11
5.0 Dimensions and Fixings
© Baxi Heating UK Ltd 2013
360° Orientation
Flue Ø 100mm
DC
B
A
E
G
F
At least 1.5°
H
J
Heating
Flow
(22mm)
Gas
Inlet
(22mm)
Heating
Return
(22mm)
Pressure
Relief
Valve
(15mm)
Condensate
Drain
Boiler
Side
Boile
r
Side
130 mm
25
mm 130 mm 65 mm40 mm
162.5 mm
Tap Rail
Dimensions
A700mm
B300*mm
*This can be reduced to 290mm by
removing the boiler control access flap
C390mm
D116mm Ø Min.
E160mm
(207mm for 80/125mm
flue systems)
F130mm
G106mm
H228mm
J162mm

12
6.0 System Details
© Baxi Heating UK Ltd 2013
6.1 Treatment of Water Circulating Systems
1. All recirculatory water systems will be subject to corrosion
unless they are flushed and an appropriate water treatment is
applied. To prevent this, follow the guidelines given in BS
7593 “Treatment of Water in Domestic Hot Water Central
Heating Systems” and the treatment manufacturers
instructions.
2. Treatment must involve the use of a proprietary cleanser,
such as Sentinel X300 or X400, or Fernox F3 and an inhibitor
such as Sentinel X100 or Fernox MB-1.
3. Full instructions are supplied with the products, for further
information contact Sentinel (0800 389 4670) or Fernox
(0870 870 0362).
Failure to flush and add inhibitor to the system will
invalidate the appliance warranty.
4. It is important to check the inhibitor concentration after
installation, system modification and at every service in
accordance with the inhibitor manufacturer’s instructions.
(Test kits are available from inhibitor stockists.)
5. For information or advice regarding any of the above
contact Technical Enquiries 0844 871 1555.
6.2 Bypass
1. The boiler is fitted with an automatic integral bypass. Some
systems may require an additional external bypass.
6.3 System Control
1. Further external controls (e.g. room thermostat sensors)
MUST be fitted to optimise the economical operation of the
boiler in accordance with Part L of the Building Regulations
(2010). A range of optional controls are available. Full details
are contained in the relevant Sales Literature.

13
6.0 System Details
© Baxi Heating UK Ltd 2013
Fig. 4
Fig. 6
Stop
Valve
Double
Check
Valve
DHW
Mains
Inlet
CH
Return
Temporary
Loop
Pressure Relief Valve
Discharge Pipe
Stop
Valve
Fig. 5
6.4 System Filling and Pressurising
1. 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.
2. The filling method adopted must be in accordance with all
relevant water supply regulations and use approved
equipment.
3. 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”.
4. The sealed primary circuits may be filled or replenished by
means of a temporary connection between the 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.
6.5 Expansion Vessel (Central Heating only)
1. The appliance expansion vessel is pre-charged to 0.5 bar.
Therefore, the minimum cold fill pressure is 0.5 bar. The
vessel is suitable for correct operation for system capacities
up to 100 litres (32 kW model - 155 litres). For greater
system capacities an additional expansion vessel must be
fitted. For GB refer to BS 7074 Pt 1. For IE, the current
edition of I.S. 813 “Domestic Gas Installations”.
6.6 Safety Pressure Relief Valve (Fig. 6)
1. The pressure relief valve is set at 3 bar, therefore all
pipework, fittings, etc. should be suitable for pressures in
excess of 3 bar and temperature in excess of 100°C.
2. The pressure relief discharge pipe should be not less than
15mm dia, run continuously downward, and discharge
outside the building, preferably over a drain. It should be
routed in such a manner that no hazard occurs to occupants
or causes damage to wiring or electrical components. The
end of the pipe should terminate facing down and towards
the wall (Fig. 6a).
3. The discharge must not be above a window, entrance or
other public access. Consideration must be given to the
possibility that boiling water/steam could discharge from the
pipe.
4. A remote relief valve kit is available to enable the boiler to
be installed in cellars or similar locations below outside
ground level (kit no. 5121379).
5. A boiler discharge pump is available, part no. 720648301.
This pump will dispose of both condensate & high
temperature water from the relief valve. It has a maximum
head of 5 metres.
Control Box removed
for clarity
Fig. 6a
The end of the pipe should
terminate facing down and
towards the wall

14
7.0 Site Requirements
© Baxi Heating UK Ltd 2013
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 7.3).
2. Where the boiler is sited in an unheated enclosure and
during periods when the heating system is to be unused it is
recommended that the permanent live is left on to give
BOILER frost protection. NOTE: THIS WILL NOT PROTECT
THE SYSTEM !
3. If the boiler is 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.
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 Clearances (Figs. 8 & 9)
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.
*This is MINIMUM recommended dimension. Greater
clearance will aid installation and maintenance.
7.3 Ventilation of Compartments
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.
150mm* Min
700mm
390mm
175mm Min
(300mm Min if
using 80/125mm
flueing system)
5mm Min
5mm Min
450mm Min
For Servicing
Purposes
Fig. 8
Fig. 9
In Operation
5mm Min
At least 1.5°
300mm
(290mm with flap removed)

15
7.0 Site Requirement
© Baxi Heating UK Ltd 2013
7.4 Gas Supply
1. The gas installation should be in accordance with the
relevant standards. In GB this is BS 6891 (NG) or BS 5482
Pt. 1 (LPG). In IE this is the current edition of I.S. 813
“Domestic Gas Installations”.
2. The connection to the appliance is a 22mm copper tail
located at the rear of the gas service cock (Fig. 10).
3. Ensure that the pipework from the meter to the
appliance is of adequate size, and the demands of any
other gas appliances in the property are taken into
consideration. Do not use pipes of a smaller diameter than
the boiler gas connection (22mm).
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 ~ 50Hzfused 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.
7.6 Bath & Shower Rooms
1. If the boiler is fitted in a room containing a bath or
shower it can be fitted in zone 2, (Figs. A & B shows zone
dimensions for a bathtub. For other examples refer to 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.
Fig. 10
Gas Service Cock
Zone 2
Zone 1
Zone 0
Zone 2
Zone 2
Window
Recess
Window
Recess
0.6 m
Ceiling
Outside Zones
Zone 2
Zone 1
Zone 0
2.25 m
Window Recess
Zone 2
0.6 m
Fig. A
Fig. B
In GB Only
In GB Only

16
7.0 Site Requirements
© Baxi Heating UK Ltd 2013
7.7 Condensate Drain
FAILURE TO INSTALL THE CONDENSATE
DISCHARGE PIPEWORK CORRECTLY WILL AFFECT
THE RELIABLE OPERATION OF THE BOILER.
CAREFUL CONSIDERATION MUST BE GIVEN TO THE
POSSIBILITY OF THE PIPEWORK BEING SUBJECT TO
FREEZING CONDITIONS AND APPROPRIATE
MEASURES TAKEN TO PREVENT BLOCKAGE.
CORRECT INSTALLATION IN ACCORDANCE WITH
THIS SECTION WILL CONSIDERABLY MINIMISE THE
LIKELIHOOD OF BLOCKAGE AND SUBSEQUENT
BOILER LOCK-OUT.
A CONDENSATE DISCHARGE PUMP AND PIPE ‘TRACE
HEATING’ ARE AVAILABLE AS ACCESSORIES - see
paragraphs 7.7.12 to 7.715 for further details.
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 EXCEPT
when employing a suitable condensate pump in basement
and cellar or similar applications.
The boiler condensate trap incorporates a seal of 75mm,
therefore it is unnecessary to install an air break and trap
in the discharge pipework.
1. The condensate outlet will accept 21.5mm (3/4in) plastic
overflow pipe. It is strongly recommended that this
discharges internally into the household drainage system.
Where this is not possible, discharge into an outside drain is
permissible providing every possible precaution is taken to
prevent freezing.
2. Ensure the discharge of condensate complies with any
national or local regulations in force. BS 6798 & Part H1 of
the Building Regulations give further detailed 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 of the correct
design to prevent sagging.
6. It is advisable that the full length of condensate pipe is run
internally and preferably be less than 3 metres.
7. Internal runs greater than 3 metres or runs in cold areas
should use 32mm waste pipe.
8. External runs MUST be a MINIMUM of 32mm and fully
insulated with material suitable for external use.
9. If the boiler is fitted in an unheated location the entire
condensate discharge pipe should be treated as an external
run and sized and insulated accordingly.
10. 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
and any burrs on cut pipe removed.
21.5mm
2.5° Minimum fall
i) Termination to an internal soil and
vent pipe
450mm min*
Boiler
2.5° Minimum fall
ii) External termination via internal discharge branch
e.g sink waste - downstream*
Sink
Pipe must terminate above
water level but below
surrounding surface. Cut
end at 45°
50mm per metre of pipe run
50mm per metre of pipe run
*450mm is applicable to
properties up to 3 storeys.
For multi-storey building
installations consult BS 6798.
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) downstream of the trap
iii) to a drain or gully
iv) to a purpose made soakaway
v) pumped into an internal discharge branch (e.g. sink waste) downstream of the trap
vi) pumped into an external soil & vent pipe
vii) to a drain or gully with extended external run & trace heating
It is strongly recommended to discharge internally into the household
drainage system. If connecting to a rain water drain, that drain MUST
discharge into a foul drain.
*It is NOT RECOMMENDED
to connect upstream of the
sink or other waste water
receptacle !
32mm Insulation

17
7.0 Site Requirement
© Baxi Heating UK Ltd 2013
7.7 Condensate Drain (cont.)
11. 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.
Boiler
2.5° Minimum fall
iii) Termination to a drain or gully
Boiler
500mm min
2.5° Minimum fall
iv) Termination to a purpose made soakaway
Holes in the soak-away must
face away from the building
50mm per metre of pipe run
50mm per metre of pipe run
Further specific requirements for soakaway
design are referred to in BS 6798.
Pipe must terminate above
water level but below
surrounding surface. Cut
end at 45°

18
7.0 Site Requirement
© Baxi Heating UK Ltd 2013
7.7 Condensate Drain (cont.)
12. A boiler discharge pump is available, ‘MULTIFIT’
part no. 720648301. This pump will dispose of both
condensate & high temperature water from the relief valve.
It has a maximum head of 5 metres. Follow the instructions
supplied with the pump.
13. Condensate Drain Pipe ‘Trace Heating’ Elements are
available in various lengths. ‘MULTIFIT’ part nos.:-
1 metre 720644401
2 metre 720664101
3 metre 720664201
5 metre 720664401*
*Where the drain is between 3 & 5 metres a 5 metre kit can
be used and “doubled back” upon itself.
14. It is possible to fit the element externally on the
condensate drain or internally as detailed in the instructions
provided.
15. The fitting of a ‘Trace Heating’ Element is NOT a
substitute for correct installation of the condensate drain.
ALL requirements in this section must still be adhered to.
Boiler
vi) pumped into an external soil & vent pipe
2.5° Minimum fall
50mm per metre of pipe run
Condensate Pump
Unheated Location
(e.g. Garage)
Basement or similar
(heated)
Boiler
2.5° Minimum fall
50mm per metre of pipe run
Pipe must terminate above
water level but below
surrounding surface. Cut
end at 45°
The ‘Trace Heating’ element
must be installed in accordance
with the instructions supplied.
External runs & those in
unheated locations still require
insulation.
vii) to a drain or gully with extended
external run & trace heating
Boiler
v) pumped into an internal discharge branch
(e.g. sink waste) downstream of the trap
Pipe must terminate above
water level but below
surrounding surface. Cut
end at 45°
2.5° Minimum fall
50mm per metre of pipe run
Condensate Pump
Sink
Basement or similar
(heated)

19
7.0 Site Requirements
© Baxi Heating UK Ltd 2013
7.8 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. If a terminal is less than 2 metres above a balcony, above
ground or above a flat roof to which people have access,
then a suitable terminal guard must be provided.
IMPORTANT:
• 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.
*4. Reduction to the boundary is possible down to 25mm
but flue deflector part no. 5111068 must be used.
N
I
I
G
F
M
I
AAF
H
J,K
D
E
H
Likelyflue positions requiring
aflue terminal guard
C
RA
I
J,K
I
L
S
B
T
U
Fig. 12
Fig. 11
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
Opening Window
or Door
150mm
MIN.
IMPORTANT: If fitting a Plume
Displacement Flue Kit, the air inlet
must be a minimum of 150mm from
any opening windows or doors (see
Section 9.0).
Plume
Displacement Kit
Air Inlet
Fig. 13
Terminal Position with Minimum Distance (Fig. 12) (mm)
A1Directly below an opening, air brick, opening
windows, etc. 300
B1Above an opening, air brick, opening window etc. 300
C1Horizontally to an opening, air brick, opening window etc. 300
D2Below gutters, soil pipes or drain pipes. 25 (75)
E2Below eaves. 25 (200)
F2Below balconies or car port roof. 25 (200)
G2From a vertical drain pipe or soil pipe. 25 (150)
H2From an internal or external corner. 25 (300)
I Above ground, roof or balcony level. 300
JFrom 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
T Adjacent to windows or openings on pitched and flat roofs 600
U Below windows or openings on pitched roofs 2000
1In 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.
2Only ONE 25mm clearance is allowed per installation. If one of the dimensions
D, E, F, G or H is 25mm then the remainder MUST be as shown in brackets, in
accordance with B.S.5440-1.
*

20
8.0 Flue
© Baxi Heating UK Ltd 2013
Horizontal
Flues
(ii)
(i)
Plume Displacement Kit 60 /100 dia
1M Extensions 45° & 93° elbows
are also available.
NOTE: Horizontal flue pipes should always be installed with a fall of at least 1.5°
from the terminal to allow condensate to run back to the boiler.
(ii)
(i)
This bend is equivalent to
1 metre
Total equivalent length =
A+B+C+2 x 90° Bends
B
AC
This bend is equivalent to
1 metre
8.1 Horizontal Flue Systems
1. The standard flue is suitable only for horizontal
termination applications.
2. All fittings should be fully engaged. The approximate
engagement is 40mm. Apply the lubricant supplied to the
seal on each fitting to aid assembly.
3. Maximum permissible equivalent flue lengths are:-
(60/100) (80/125)
Horizontal Concentric 10 metres 20 metres
4. Any additional “in line” bends in the flue system must be
taken into consideration.
Their equivalent lengths are:-
Concentric Pipes:
135° bend 0.5 metres
93° bend 1.0 metres
5. The elbow supplied with the standard horizontal
telescopic flue kit is not included in any equivalent length
calculations.
NOTE: Flue length is measured from point (i) to (ii) as
shown.
IMPORTANT
SUPPORT - All flue systems MUST be securely
supported a MINIMUM of once every metre. It is
recommended that every straight piece is supported
irrespective of length. Additional supports are available
as accessories.
VOIDS - Consideration must be given to flue systems
in voids and the provision of adequate access for
subsequent periodic visual inspection.
6. Read this section in conjunction with the Flue Installation
Guide supplied with the boiler.