Baxi Potterton Gold HE A Range User Manual
You can rely on  
Installation & Service Instructions  
Gold HE A  
Range  
Condensing  
Combination Boiler  
These instructions include the Benchmark Commissioning  
Checklist and should be left with the user for safe keeping.  
© Baxi Heating UK Ltd 2008  
Installer Notification Guidelines  
Choose Building  
Regulations Notification  
Route  
Competent Person's  
Building Control  
Self Certification Scheme  
Contact your relevant Local  
Authority Building Control  
(LABC) who will arrange  
an inspection or contact  
a government approved  
inspector  
Install and Commission this  
appliance to manufacturer's  
instructions  
Complete the  
Benchmark Checklist  
If you notify via CORGI Scheme,  
CORGI will then notify the  
relevant Local Authority  
Building Control Scheme  
on member's behalf  
Install and Commission this  
appliance to manufacturer's  
instructions  
Scheme Members only  
Complete the  
Benchmark Checklist  
Call CORGI on: 0800 408 1007  
or log onto:  
www.corgi-notify.com  
within 10 days  
You must ensure that the  
notification number issued by  
CORGI is written onto the  
Benchmark Checklist  
CORGI will record the data and  
will send a certificate of  
LABC will record the data  
and will issue a  
compliance to the property  
certificate of compliance  
3
© Baxi Heating UK Ltd 2008  
Legislation  
IMPORTANT - Installation, Commissioning, Service & Repair  
This company declare that no substances harmful to health  
are contained in the appliance or used during appliance  
manufacture.  
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.  
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, this must be carried out by a competent person as stated in the Gas Safety  
(Installation & Use) Regulations.  
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:  
Definition of competence: A person who works for a CORGI registered company and  
holding current certificates in the relevant ACS modules, is deemed competent.  
• 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.  
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.  
• 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.  
Warning - Check the information on the data plate is compatible with local supply  
conditions.  
All CORGI registered installers carry a CORGI identification card and have a  
All systems must be thoroughly flushed and treated with  
inhibitor (see section 6.2).  
registration number. You can check your installer is registered by telephoning  
0800 915 0485 or writing to:-  
1 Elmwood,  
Chineham Park,  
Crockford Lane,  
Basingstoke. RG24 8WG  
Codes of Practice - refer to the most recent version  
or check online at www.trustcorgi.com  
In GB the following Codes of Practice apply:  
Standard  
BS 6891  
BS 5546  
Scope  
Gas Installation.  
Installation of hot water supplies for domestic  
purposes.  
Forced circulation hot water systems.  
Installation of gas fired hot water boilers.  
Flues.  
The boiler meets the requirements of Statutory Instrument “ The Boiler (Efficiency)  
o
BS 5449  
BS 6798  
BS 5440 Part 1  
BS 5440 Part 2  
BS 7074  
Regulations 1993 N 3083” 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:-  
Ventilation.  
Expansion vessels and ancillary equipment for  
sealed water systems.  
BS 7593  
Treatment of water in domestic hot water  
central heating systems.  
Type test for purpose of Regulation 5 certified by:  
Notified Body 0085.  
In IE the following Codes of Practice apply:  
Standard  
I.S. 813  
Scope  
Product/Production certified by:  
Notified Body 0085 & 0086.  
Domestic Gas Installations.  
The following standards give valuable additional information;  
BS 5546  
Installation of hot water supplies for domestic  
purposes.  
BS 5449  
BS 7074  
Forced circulation hot water systems.  
Expansion vessels and ancillary equipment for  
sealed water systems.  
For GB/IE only.  
BS 7593  
Treatment of water in domestic hot water  
central heating systems.  
4
© Baxi Heating UK Ltd 2008  
Safe Manual Handling  
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 !!  
5
© Baxi Heating UK Ltd 2008  
CONTENTS  
Section  
1.0  
Page  
Introduction  
7
2.0  
3.0  
4.0  
5.0  
6.0  
7.0  
8.0  
9.0  
General Layout  
8
9
Appliance Operation  
Technical Data  
10  
11  
12  
15  
19  
24  
28  
34  
37  
38  
40  
49  
50  
51  
52  
58  
Dimensions and Fixings  
System Details  
Site Requirements  
Flue Options  
Plume Displacement  
10.0 Installation  
11.0 Commissioning  
12.0 Completion  
13.0 Servicing  
14.0 Changing Components  
15.0 Combustion Check  
16.0 Electrical  
17.0 Short Parts List  
18.0 Fault Finding  
Benchmark Checklist  
6
© Baxi Heating UK Ltd 2008  
1.0 Introduction  
1.1  
Description  
1. The Potterton Gold Combi HE A is a fully automatic gas  
fired wall mounted condensing combination boiler. It is room  
sealed and fan assisted, and will serve central heating and  
mains fed domestic hot water.  
Case Front Panel  
2. The boiler is set to give a maximum output of :-  
24 models - 24 kW DHW  
21 kW CH (Condensing)  
28 models - 28 kW DHW  
25.9 kW CH (Condensing)  
33 models - 33 kW DHW  
30.3 kW CH (Condensing)  
3. It is designed for use on Natural Gas (G20).  
4. The boiler is suitable for use only on fully pumped sealed  
heating systems. Priority is given to domestic hot water.  
5. The boiler is supplied with a filling loop and integral timer.  
6. The boiler data badge gives details of the model, serial  
number and Gas Council number and is situated on the inner  
door panel. It is visible when the case front panel is removed  
(Fig. 1).  
Lower Door  
Panel  
7. The boiler model name and serial number are also shown  
on the information label on the rear or the lower door panel.  
This is for user reference.  
8. The boiler is intended to be installed in residential /  
commercial / light industrial E.M.C. environments on a  
governed meter supply only.  
Data Badge  
Fig. 1  
Information Label  
9. The boiler must be installed with one of the purpose  
designed flues such as the standard horizontal flue kit, part no.  
5118489.  
9. All systems must be thoroughly flushed and treated with  
inhibitor (see section 6.2).  
1.2  
Contents of Pack  
1. Boiler Unit  
2. Wall Plate (inc. taps)  
3. Set of Pipe (inc. nuts)  
4. Template  
5. Quick Fit Guide  
6. Literature Pack  
7. Filling Loop  
7
© Baxi Heating UK Ltd 2008  
2.0 General Layout  
2.1  
Layout  
23  
1
1.  
Expansion Vessel  
15  
2.  
Automatic Air Vent  
DHW Plate Heat Exchanger  
Circulation Pump  
3.  
22  
4.  
5.  
Drain Off Point  
14  
6.  
Pressure Relief Valve  
Optional Integral Timer Position  
Central Heating System Pressure Gauge  
PCB  
7.  
13  
8.  
21  
9.  
16  
20  
10.  
11.  
12.  
13.  
14.  
15.  
16.  
17.  
18.  
19.  
20.  
21.  
22.  
23.  
24.  
25.  
26.  
27.  
28.  
Control Box  
3-Way Valve Assembly  
Condensate Trap  
Flame Sensing Electrode  
Spark Electrode  
Primary Heat Exchanger  
Fan Assembly  
On/Off/Reset Selector Switch  
Central Heating Temperature Control  
Hot Water Temperature Control  
Venturi  
10  
Air/Gas Collector  
9
8
Combustion Box Cover & Burner  
Igniter  
7
Burner On Light  
Central Heating Mode Light  
Domestic Hot Water Mode Light  
Display  
12  
Integral Timer  
2
11  
3
5
4
6
25  
26  
2
Reset  
3
0
4
0
bar  
24  
18  
19  
28  
17  
8
27  
8
© Baxi Heating UK Ltd 2008  
3.0 Appliance Operation  
1
Central Heating Circuit  
3.1  
Central Heating Mode (Fig. 2)  
27  
1. With a demand for heating, the pump circulates water  
through the primary circuit.  
2
2. Once main burner ignites the fan speed controls the gas  
rate to maintain the heating temperature measured by the  
temperature sensor.  
3
5
4
7
26  
20  
6
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.  
25  
8
4. When the demand is satisfied the burner is extinguished  
and the pump continues to run for a period of 3 minutes  
(Pump Overrun).  
24  
18  
22  
9
11  
23  
3.2  
Domestic Hot Water Mode (Fig. 3)  
21  
10  
1. Priority is given to the domestic hot water supply. A  
demand at a tap or shower will override any central heating  
requirement.  
17  
16  
15  
14  
13  
12  
19  
2. The flow of water will operate the Hall Effect Sensor  
which requests the 3 way valve to change position. This will  
allow the pump to circulate the primary water through the  
DHW plate heat exchanger.  
Fig. 2  
Key  
1
2
3
4
5
6
7
8
9
Primary Heat Exchanger  
Burner  
Ignition Electrodes  
Flame Sensing Electrode  
Gas Valve  
Pump  
Automatic Air Vent  
Plate Heat Exchanger  
15 Domestic Hot Water Outlet  
16 Heating Flow  
17 Pressure Gauge  
18 Water Pressure Sensor  
19 Automatic By-Pass  
20 Fan  
21 Diverter Valve Assembly  
22 Diverter Valve Motor  
23 Domestic Hot Water Flow Temperature Sensor  
24 Safety Thermostat  
25 Central Heating Temperature Sensor  
26 Expansion Vessel  
3. The burner will light automatically and the temperature of  
the domestic hot water is controlled by the temperature  
sensor.  
4. When the domestic hot water demand ceases the burner  
will extinguish and the diverter valve will remain in the  
domestic hot water mode, unless there is a demand for  
central heating.  
Flow Sensor with Filter & Regulator  
10 Pressure Relief Valve  
11 Boiler Drain Point  
12 Heating Return  
13 Cold Water Inlet On/Off Valve and Filter  
14 Gas Inlet  
27 Heat Exchanger Air Vent  
IMPORTANT: When the selector switch is in the ‘0’  
(Off) position the electrical supply to the boiler is isolated.  
The boiler will not operate and the integral timer will  
require resetting once the selector switch is set to either  
Position (i) or Position (ii).  
1
2
Domestic Hot Water Circuit  
27  
3.3  
Frost Protection Mode  
1. The frost protection mode is integral to the appliance and  
functions only with the selector switch (see Section 2.1) in  
the domestic hot water and central heating position. If the  
system temperature falls below 5° C then the boiler will fire  
on its minimum setting until a flow temperature of 30° C is  
reached.  
3
5
4
7
26  
20  
6
3.4  
Pump Protection  
25  
24  
8
1. With the selector switch (see Section 2.1) in either the  
central heating or central heating and domestic hot water  
position, the pump will automatically operate for 1 minute in  
every 24 hours to prevent sticking.  
18  
22  
9
11  
23  
21  
10  
17  
16  
15  
14  
13  
12  
19  
Fig. 3  
9
© Baxi Heating UK Ltd 2008  
4.0 Technical Data  
4.1  
Gold Combi 24, 28 & 33 HE A  
NO Class  
Appliance Type  
C13  
C33  
C53  
5
Inlet Pressure (Natural Gas - G20)  
mbar 20  
x
Appliance Category  
Heat Input CH (Net)  
CAT I  
Central Heating Primary Circuit  
Pressures  
2H  
Injector (Natural Gas - G20)  
Max  
20.5  
24.7  
28.9  
Min  
7
bar  
3
7.5mm (24&28 model) 12mm(33 model)  
24 model  
28 model  
33 model  
kW  
kW  
kW  
Safety Discharge  
Electrical Supply  
230V~ 50H  
z
Max Operating  
Min Operating  
Recommended Operating Range  
2.5  
0.5  
1-2  
9
(Appliance must be connected to an  
earthed supply)  
9.7  
Heat Input CH (Gross)  
Max  
22.7  
27.4  
32.1  
Min  
7.8  
DHW Circuit  
Pressures  
Max Operating  
Min Operating  
bar  
Power Consumption  
24 model  
28 model  
33 model  
kW  
kW  
kW  
155W (24 & 28 model) 160W (33 model)  
8
0.15  
10  
Electrical Protection  
IPX0D  
10.8  
Flow Rates  
(24)  
l/min  
(28)  
l/min  
(33)  
l/min  
Heat Output CH (Non-Condensing)  
External Fuse Rating  
3A  
Max  
Min  
6.8  
8.7  
9.4  
DHW Flow Rate  
o
Internal Fuse Rating  
Condensate Drain  
To accept 21.5mm ( /4 in) plastic waste pipe  
F2L  
@ 30 CRise  
11.43  
9.8  
2
13.3  
11.5  
2
15.7  
13.5  
2
24 model  
28 model  
33 model  
kW  
kW  
kW  
20  
24  
28  
DHW Flow Rate  
3
o
@ 35 CRise  
Min Working  
DHW Flow Rate  
Flue Terminal  
Dimensions  
Diameter  
Projection  
100mm  
125mm  
Heat Output CH (Condensing)  
Max  
Min  
7.4  
Pump  
Available Head  
Connections  
Gas Supply  
Central Heating Flow  
Central Heating Return  
Cold Water Mains Inlet  
DHW Flow  
copper tails  
22mm  
24 model  
28 model  
33 model  
kW  
kW  
kW  
21  
See graph below  
- (For Central Heating  
-
25.9  
30.3  
9.5  
-
-
-
-
-
22mm  
22mm  
15mm  
15mm  
Expansion Vessel  
only. Integral with appliance)  
10.2  
bar  
0.5  
Heat Input DHW (Net)  
Max  
24.7  
28.9  
34  
Min Pre-charge Pressure  
24 model  
28 model  
33 model  
kW  
kW  
kW  
Pressure Relief Discharge  
15mm  
(24,28) (33)  
litre  
125  
Max Capacity of  
CH System  
litre  
155  
Outercase Dimensions  
Casing Height  
Overall Height Inc Flue Elbow  
Casing Width  
- 780mm  
- 965mm  
- 450mm  
- 345mm  
Heat Input DHW (Gross) Max  
Primary Water Content  
of Boiler (unpressurised)  
24 model  
28 model  
33 model  
kW  
kW  
kW  
27.4  
32.1  
37.7  
2.5  
2.8  
Casing Depth  
Clearances  
Temperatures  
C.H. Flow Temp (adjustable)  
Above Casing  
Below Casing  
Front  
Front  
L.H. Side  
R.H. Side  
200 mm Min  
200 mm Min  
450 mm Min (For Servicing)  
5 mm Min (In Operation)  
5 mm Min  
25°C to 80°C max ( 5°C)  
Heat Output DHW  
Max  
24  
24 model  
28 model  
33 model  
kW  
D.H.W. Flow Temp (adjustable)  
kW  
kW  
28  
35°C to 60°C max ( 5°C)  
dependent upon flow rate  
5 mm Min (In Operation)  
33  
Weights (kg)  
Max Gas Rate (Natural Gas - G20)  
(24) (28) (33)  
Packaged Boiler Carton 48.6 49.2 51  
Installation Lift Weight 43.6 44.2 46  
(After 10 mins)  
3
24 model  
28 model  
33 model  
m /h  
2.61  
3.1  
3
m /h  
3
m /h  
3.6  
Pump - Available Head  
5.5  
5
4.5  
SEDBUK Declaration  
4
The efficiency is 91.1% (all models)  
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.  
3.5  
3
2.5  
2
1.5  
1
0.5  
0
0
200  
400  
600  
800  
1000  
1200  
Flow Rate (l/h)  
10  
© Baxi Heating UK Ltd 2008  
5.0 Dimensions and Fixings  
Dimensions  
A 780mm  
E
At least 1.5°  
G
A
B 345mm  
C 450mm  
D 116mm Ø Min.  
E 185mm  
(207mm for 80/125mm  
flue systems)  
F 145mm  
G 131mm  
B
H 180mm  
360° Orientation  
J
270mm  
H
J
D
C
Flue Ø 100mm  
F
Tap Rail  
32.5 mm  
Condensate  
Drain  
65 mm  
65 mm  
65 mm  
Cold Water  
65 mm  
65 mm  
Heating  
Return  
(22mm)  
Pressure Relief  
Heating  
Flow  
(22mm)  
Domestic Hot  
Water Outlet  
(15mm)  
Gas  
Inlet  
(22mm)  
Valve  
(15mm)  
Inlet  
(15mm)  
11  
© Baxi Heating UK Ltd 2008  
6.0 System Details  
6.1  
Information  
1. The Potterton Gold Combi HE A Condensing Combination  
Boiler is a ‘Water Byelaws Scheme - Approved Product’.  
To comply with the Water Byelaws your attention is drawn to  
the following installation requirements and notes (IRN).  
a) IRN 001 -  
See text of entry for installation  
requirements and notes.  
Byelaw 14.  
b) IRN 302 -  
2. Reference to the WRc publications, ‘Water fittings and  
materials directory’ and ‘Water supply byelaws guide’ give full  
details of byelaws and the IRNs.  
6.2  
Central Heating Circuit  
1. The appliance is suitable for fully pumped SEALED SYSTEMS  
ONLY.  
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 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.)  
• For information or advice regarding any of the above contact  
Technical Enquiries.  
6.3  
Bypass  
1. The boiler is fitted with an automatic integral bypass.  
6.4  
System Control  
1. A 24 hour electro - mechanical timer is supplied fitted to  
the boiler.  
2. Further external controls (e.g. room thermostat) should be  
fitted to optimise the economical operation of the boiler.  
12  
© Baxi Heating UK Ltd 2008  
6.0 System Details  
6.5  
System Filling and Pressurising (Fig. 4)  
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.  
Double  
Check  
Valve  
Stop  
Valve  
Stop  
Valve  
A filling loop & instructions are provided with the boiler  
2. The filling method adopted must be in accordance with all  
relevant water supply regulations and use approved  
equipment.  
Temporary  
Hose  
DHW  
Mains  
Inlet  
CH  
Return  
Fig. 4  
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.  
6.6  
Expansion Vessel (Central Heating only)  
Filling Loop  
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 125 litres (24, 28 models) 155 litres (33 models). 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”.  
Fig. 5  
6.7  
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.  
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).  
Fig. 6  
Pressure Relief Valve  
Discharge Pipe  
13  
© Baxi Heating UK Ltd 2008  
6.0 System Details  
6.8  
Domestic Hot Water Circuit (Fig. 7)  
1. All DHW circuits, connections, fittings, etc. should be fully  
in accordance with relevant standards and water supply  
regulations.  
Other Tap  
Outlets  
2. Your attention is drawn to:  
for GB: Guidance G17 to G24 and recommendation R17 to  
R24 of the Water Regulations Guide.  
for IE: the current edition of I.S. 813 “Domestic Gas  
Installations”.  
Boiler  
Expansion  
Vessel  
3. A single check valve must be fitted as shown in Fig. 7 to  
prevent backflow to the supply pipe and to ensure the  
efficient operation of the expansion vessel which is required  
to accommodate the thermal expansion of the water.  
Check  
Valve  
Pressure Reducer  
Valve  
4. When the domestic water system includes any device  
which prevents water expanding back towards the supply  
(check valve, loose jumpered stopcock, water meter, water  
treatment device) then an expansion vessel must be fitted  
To Hot  
Taps  
Stop Tap  
1
(eg. Zilmet 160ml, R /2 15bar).  
5. If the hot water expansion is not provided for, then high  
pressures can develop which may result in damage to fittings  
and devices on the system.  
Fig. 7  
6. The boiler’s maximum working mains pressure is 8 bar,  
therefore all pipework, connections, fittings, etc. should be  
suitable for pressures in excess of 8 bar. A pressure reducing  
valve must be fitted for pressures in excess of 8 bar. The  
manufacturer of any outlet fittings, such as a shower valve,  
may require a lower maximum pressure. The pressure  
reduction must take account of all fittings connected to the  
DHW system.  
6.9  
Showers  
1. If a shower control is supplied from the appliance it  
should be of the thermostatic or pressure balanced type.  
Thermostatic type shower valves provide the best comfort  
and guard against water at too high a temperature. Existing  
controls may not be suitable - refer to the shower valve  
manufacturer.  
6.10  
Hard Water Areas  
1. If the area of the installation is recognised as a HARD  
WATER AREA then a suitable device should be fitted to  
treat the mains water supply to the boiler. Contact your  
Water Distribution Company for advice on suitable devices.  
14  
© Baxi Heating UK Ltd 2008  
7.0 Site Requirements  
450mm  
5mm Min  
5mm Min  
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).  
200mm Min  
(300mm Min if  
using 80/125mm  
flueing system)  
2. If the boiler is sited in an unheated enclosure then it is  
recommended to leave the ON/OFF Selector Switch in the  
domestic hot water and central heating position to give frost  
protection.  
780mm  
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).  
200mm Min  
Fig. 8  
7.2  
Clearances (Figs. 8 & 9)  
1. A flat vertical area is required for the installation of the  
boiler.  
At least 1.5°  
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.  
450mm Min  
For Servicing  
Purposes  
5mm Min  
In Operation  
Fig. 9  
15  
© Baxi Heating UK Ltd 2008  
7.0 Site Requirement  
Gas Service Cock  
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.  
7.4  
Gas Supply  
1. The gas installation should be in accordance with the  
relevant standards. In GB this is BS 6891. In IE this is the  
current edition of I.S. 813 “Domestic Gas Installations”.  
Fig. 10  
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. Do not use pipes of a smaller  
diameter than the boiler gas connection (22mm).  
Zone 2  
Window  
Recess  
Zone 1  
Zone 0  
7.5  
Electrical Supply  
Zone 2  
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.  
Zone 3  
0.6 m  
2.4 m  
Window  
Recess  
2. The mains supply is 230V ~ 50H fused at 3A.  
z
Zone 2  
NOTE: The method of connection to the electricity  
supply must facilitate complete electrical isolation of the  
appliance.  
Zone 3  
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.  
Fig. 11  
In GB Only  
7.6  
Bath & Shower Rooms  
Ceiling  
Outside Zones  
1. As the boiler is fitted with an integral timer when  
installed in a room containing a bath or shower it cannot  
be fitted in zones 1 or 2. (Figs. 11 & 12 shows zone  
dimensions for a bathtub. For other examples refer to  
Section 601 of the Current I.E.E. Wiring Regulations).  
Reference must be made to the relevant requirements.  
In GB this is the current I.E.E. Wiring Regulations and  
Building Regulations.  
Zone 3  
Zone 2  
Window  
Recess  
Zone 2  
Outside  
Zones  
3.0 m  
Zone 3  
2.25 m  
Zone 1  
Zone 0  
Zone 2  
In IE reference should be made to the current edition of I.S.  
813 “Domestic Gas Installations” and the current ETCI  
rules.  
0.6 m  
2.4 m  
Fig. 12  
In GB Only  
16  
© Baxi Heating UK Ltd 2008  
7.0 Site Requirements  
7.7  
Condensate Drain  
Termination to an internal soil and  
vent pipe  
Boiler  
FAILURE TO INSTALL THE CONDENSATE DISCHARGE  
PIPEWORK CORRECTLY WILL AFFECT THE RELIABLE  
OPERATION OF THE BOILER  
The condensate discharge pipe MUST NOT RISE at any point  
along its length. There MUST be a fall of AT LEAST 2.5°  
(50mm per metre) along the entire run.  
3
1. The condensate outlet will accept 21.5mm ( /4in) plastic  
overflow pipe which should generally discharge internally into  
the household drainage system. If this is not possible, discharge  
into an outside drain is acceptable.  
450mm min  
Fig. 13  
2. Ensure the discharge of condensate complies with any  
national or local regulations in force.  
External termination via internal discharge  
branch  
BS 6798:2000 & Part H1 of the Building Regulations give  
further guidance.  
Boiler  
e.g sink waste - downstream  
3. The discharge pipe should be run in a proprietary drain pipe  
material e.g. PVC, PVC-U, ABS, PVC-C or PP.  
Pipe must terminate  
above water level but  
below surrounding  
surface  
4. Metal pipework is NOT suitable for use in condensate  
discharge systems.  
Sink  
5. The pipe should be a minimum of 21.5mm diameter and  
must be supported using suitably spaced clips to prevent  
sagging.  
6. It is advisable to keep the condensate pipe internal.  
Fig. 14  
7. External runs greater than 3 metres or runs in cold areas  
should use 32mm waste pipe.  
8. If the boiler is fitted in an unheated location the entire  
condensate discharge pipe should be treated as an external  
run.  
Termination to a drain or gully  
Boiler  
Pipe must terminate above  
water level but below  
surrounding surface  
9. In all cases discharge pipe must be installed to aid disposal  
of the condensate. To reduce the risk of condensate being  
trapped, as few bends and fittings as possible should be used.  
10. When discharging condensate into a soil stack or waste  
pipe the effects of existing plumbing must be considered. If soil  
pipes or waste pipes are subjected to internal pressure  
fluctuations when WC's are flushed or sinks emptied then  
back-pressure may force water out of the boiler trap and  
cause appliance lockout.  
Fig. 15  
Termination to a purpose made soak-  
away  
Examples are shown of the following methods of termination:-  
i) to an internal soil & vent pipe - Fig. 13  
Boiler  
ii) via an internal discharge branch (e.g. sink waste) - Fig. 14  
iii) to a drain or gully - Fig. 15  
500mm min  
iv) to a purpose made soakaway - Fig. 16  
Holes in the soak-away must  
face away from the building  
Fig. 16  
17  
© Baxi Heating UK Ltd 2008  
Terminal Position with Minimum Distance (Fig. 18)  
(mm)  
7.0 Site Requirements  
a
a
A
Directly below an opening, air brick, opening  
windows, etc.  
Above an opening, air brick, opening window etc.  
Horizontally to an opening, air brick, opening window etc.  
Below gutters, soil pipes or drain pipes.  
Below eaves.  
Below balconies or car port roof.  
From a vertical drain pipe or soil pipe.  
From an internal or external corner.  
300  
300  
300  
25  
25  
25  
25  
25  
300  
600  
1200  
600  
a
B
7.8  
Flue  
C
D
E
F
G
H
I
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.  
Above ground, roof or balcony level.  
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”.  
J
K
From a surface or boundary line facing a terminal.  
From a terminal facing a terminal (Horizontal flue).  
From a terminal facing a terminal (Vertical flue).  
From an opening in carport (e.g. door, window)  
into the dwelling.  
Vertically from a terminal on the same wall.  
Horizontally from a terminal on the same wall.  
From adjacent wall to flue (vertical only).  
From an adjacent opening window (vertical only).  
Adjacent to windows or openings on pitched and flat roofs  
Below windows or openings on pitched roofs  
L
1200  
1500  
300  
300  
1000  
600  
M
N
R
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.  
S
T
U
2000  
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.  
a
In addition, the terminal should be no nearer than 150 mm to an  
opening in the building fabric formed for the purpose of accommodating  
a built-in element such as a window frame. See BS 5440 Pt. 1.  
IMPORTANT:  
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  
• 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.  
300 min  
Terminal  
Assembly  
*
Plume  
Displacement Kit  
IMPORTANT: If fitting a Plume  
Displacement Flue Kit, the air inlet  
must be a minimum of 100mm from  
any opening windows or doors (see  
Section 9.0).  
TopView Rear Flue  
Fig. 17  
Property Boundary Line  
Air Inlet  
T
J,K  
U
Opening Window  
or Door  
100mm  
MIN.  
Fig. 18a  
N
R
I
D
E
A
M
I
C
I
I
S
F
B
J,K  
F
L
A
A
I
G
H
H
Likely flue positions requiring  
a flue terminal guard  
Fig. 18  
18  
© Baxi Heating UK Ltd 2008  
8.0 Flue Options  
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 soap solution to the seal on  
each fitting to aid assembly.  
Y
X
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  
93° bend  
0.5 metres  
1.0 metres  
Horizontal  
Flues  
Twin Flue Pipe  
135° bend  
91.5° bend  
0.25 metres  
0.50 metres  
4. The elbow connected to the boiler adaptor is not included  
in any equivalent length calculations.  
Plume Displacement Kit 60 /100 Ø  
5. The illustrations opposite show examples of permissible  
flue systems.  
1M Extensions, 45° & 93° bends are  
also available - see Section 9.0  
NOTE: Flue length is measured from point X to Y as  
shown.  
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.  
This bend is equivalent to  
1 metre  
C
A
Y
B
This bend is equivalent to  
1 metre  
X
Total equivalent length =  
A+B+C+2x90°Bends  
19  
© Baxi Heating UK Ltd 2008  
8.0 Flue Options  
Vertical  
Flues  
8.2  
Twin & Vertical Flue Systems  
(Twin Pipe)  
1. Maximum permissible equivalent flue lengths are:-  
(60/100)  
(80/125)  
Vertical Concentric  
Vertical Twin Pipe  
10 metres  
15 metres  
20 metres  
Y
2. Any additional “in line” bends in the flue system must be  
taken into consideration.  
X
Their equivalent lengths are:-  
Concentric Pipes:  
135° bend  
93° bend  
0.5 metres  
1.0 metres  
Twin Flue Pipe  
135° bend  
91.5° bend  
0.25 metres  
0.50 metres  
Vertical  
Flues  
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 X to Y as  
shown.  
Y
X
Total Equivalent Length =  
A+B+C+1x90°Bend  
Roof  
Terminal  
All vertical and angled runs must be included,  
measured from the boiler adaptor (point X) to the  
joint with the flue terminal (point Y). One 91.5°  
bend or two 135° bends can be included without  
reduction of the flue length.  
If further elbows are required the flue length must  
be reduced by the following amounts:-  
The total equivalent length for this example is  
= 6.5 metres.  
Y
1 metre for each 91.5° bend  
0.5 metre for each 135° bend  
AIR DUCT  
N of  
fittings/pipes  
C
o
Equivalent  
Sub total  
Length Value  
B
1m extension  
135°bend  
5
2
2
5.0m  
0.5m  
1.0m  
1m  
0.25m  
0.5m  
91.5°bend  
This bend is equivalent to  
1 metre  
Equivalent Length Air Duct = 6.5m  
FLUE DUCT  
N of  
fittings/pipes  
A
X
o
Equivalent  
Sub total  
Length Value  
1m  
1m extension  
135°bend  
5
2
2
5.0m  
0.5m  
1.0m  
0.25m  
0.5m  
91.5°bend  
Equivalent Length Flue Duct = 6.5m  
20  
© Baxi Heating UK Ltd 2008  
8.0 Flue Options  
8.3  
Flue Accessories  
A4  
Key Accessory  
FLUE GROUP A  
Concentric Flue System 100mm diameter  
A3 Telescopic Internal Flue Kit 315-500mm5119654  
A2 Telescopic Flue (inc. elbow) 315-500mm5118069  
Size  
Code No  
A2  
A
A
B
Horizontal Flue Terminal (inc. elbow)  
5118489  
Flue Extension  
1000mm 5111074  
C
D
D
U
R
P
Flue Bend  
Flue Bend  
Flue Bend (pair)  
Pipe Support (painted)  
Vertical Flue Adaptor  
Wall Liner  
93°  
135°  
135°  
5111075  
5111076  
5111085  
100Ømm 5111080  
5111070  
5111067  
S
Flue Terminal Deflector  
5111068  
B
A3  
E
FLUE GROUP N  
P
Twin Flue System 80mm diameter  
E
F
Flue Extension (pair)  
Flue Bend (pair)  
Flue Bend (2 pair)  
Vertical Flue Boiler Adaptor Kit  
Vertical Flue Adaptor  
Pipe Support (pair)  
Flue Termination Kit  
(horizontal termination)  
1000mm 5111087  
K,K1  
90°  
135°  
5111072  
5111086  
5111079  
5111084  
5111081  
G
J
H
W
Y
80mm  
80mm  
5120172  
R
D
FLUE GROUP G  
C
Concentric Flue System 80/125mm diameter  
A4 Horizontal Flue Kit  
5118580  
B
Straight Extension Kit  
Bend Kit (pair)  
Bend  
1000mm 5118584  
D
C
U
135°  
5118597  
5118588  
5118610  
91.5°  
Pipe support  
125mm  
FLUE GROUP A, N, G  
Vertical Flue Kits  
G
F
K
K1  
L
M
N
Vertical Flue Terminal (use with 5111070)  
Vertical Flue Terminal  
5111078  
5118576  
5122151  
246143  
M
H
Pitched Roof Flashing  
Roof cover plate  
Flat roof flashing  
25°/50°  
246144  
U,W  
Y
L
N
S
J
21  
© Baxi Heating UK Ltd 2008  
8.0 Flue Options  
For Twin Flue Systems fit the adaptors as follows:-  
8.4  
Flue Duct Adaptor  
Flue Duct Adaptor  
1. Engage the flue duct adaptor on the boiler adaptor,  
making sure that it is pushed down as far as possible.  
Blanking Plate  
Boiler Adaptor  
8.5  
Air duct adaptor  
1. Undo the screws securing the blanking plate to the boiler  
top panel. Discard the plate.  
2. There are three restrictor plates supplied in the kit. One  
marked ‘23’ and one marked ‘27’, these can be discarded  
The third restrictor MUST be positioned as shown in the  
diagrams below.  
3. Take one of the gaskets supplied in the kit and place on  
the boiler top panel.  
4. Align the appropriate restrictor as shown. Position the  
second gasket over the restrictor.  
5. Using the screws previously removed secure the inlet  
adaptor to the top panel.  
6. Continue to fit the twin flue system.  
Air Duct Adaptor  
Position of Restrictor  
Gasket  
Restrictor  
Gasket  
24 kW models  
28/33 kW models  
22  
© Baxi Heating UK Ltd 2008  
8.0 Flue Options  
8.6  
For Roof Terminals  
1. In the case of a pitched roof 25 - 50 degrees, position the lead  
tile to replace/flash over existing roof tiling. Make an aperture in  
the roof suitable for the lower tube of the roof terminal and  
ensure the integrity of the roof cover is maintained. The  
Approx  
1425mm  
adjustable plastic collar can either be positioned on the lead tile  
or the lower tube of the roof terminal prior to the final  
positioning of the vertical flue through the tile. Check the collar is  
correctly located to suit required roof pitch (either 25° to 38° or  
37° to 50°). From inside the roof adjust the flue to a vertical  
position and secure to the roof structure with the clamp supplied.  
2. For flat roof installations the aluminium flashing must be  
incorporated into the roof covering and the appropriate aperture  
made in the roof decking. The vertical flue is lowered onto the  
flashing making sure the collar of the flue locates securely with the  
flashing. (A mastic seal may be necessary). From inside the roof,  
adjust the flue to a vertical position and secure to the roof  
structure with the clamp supplied.  
Cut the same  
amount off the  
Air Duct &  
Air Duct  
Flue Duct  
Flue Duct  
IMPORTANT: If the boiler is not fitted immediately after the flue  
system, temporary precautions must be taken to prevent rain  
entry into the room of installation. Any precautionary measures  
must be removed prior to commissioning the boiler.  
Push Fit Adaptor  
8.7  
Flue Dimensions  
The standard horizontal telescopic flue kit allows for lengths  
between 100mm and 685mm from elbow to terminal (Fig. 19).  
The maximum permissible equivalent flue length is:  
10 metres (60/100 system)  
20 metres (80/125 system)  
Flue Deflector  
8.8  
Flue Trim  
Fig. 19  
1. The rubber flue trim supplied may be fitted to either the  
outside wall or on the inner wall of installation.  
8.9  
Terminal Guard (Fig. 21)  
Fig. 20  
1. When codes of practice dictate the use of terminal guards, they  
can be obtained from most Plumbers’ and Builders’ Merchants.  
2. There must be a clearance of at least 50mm between any part  
of the terminal and the guard.  
3. When ordering a terminal guard, quote the appliance name  
and model number.  
4. The flue terminal guard should be positioned centrally over the  
terminal and fixed as illustrated.  
8.10  
Flue Deflector (Fig. 20)  
Fig. 21  
1. If required, push the flue deflector over the terminal end and  
rotate to the optimum angle for deflecting plume. Secure the  
deflector to the terminal with screws provided.  
23  
© Baxi Heating UK Ltd 2008  
93° Elbow/Plume  
Outlet Assembly  
9.0 Plume Displacement  
60Ø Support  
Bracket  
9.1  
Plume Displacement Kit (Fig. 23)  
O Ring  
Kit No 5118638  
Content of kit  
0.9 metres  
1
1
1
2
1
1
3
1
1
0.9m 60/100 Concentric Flue  
1m 60 Dia Exhaust Flue Pipe  
Adaptor  
60Ø Exhaust  
Flue Pipe  
60 Dia Support Brackets  
93° Elbow/Plume Outlet Assembly  
Flexible Flue Trim  
60Ø Support  
Bracket  
“O” Rings  
‘Jubilee Clip  
O Ring  
Adaptor  
O Ring  
Fig. 22  
Boiler Elbow  
Flexible Flue  
Trim  
1. This kit is recommended for installations where the  
condensate plume emitted from the flue may cause a nuisance  
or affect the surroundings.  
‘Jubilee’ Clip  
2. The terminal must be positioned outside the building with  
the air inlet facing downward and outlet connection upwards.  
3. The plume outlet must always be at least 45° to the wall,  
with the ‘peak’ uppermost to prevent rain entry (Figs. 24 &  
25), and be at least 2 metres above ground level. It must be  
secured as shown in Fig. 19. The plume outlet must also be at  
least 500mm from the air inlet in any direction (Fig. 25).  
60/100Ø  
Concentric Flue  
Fig. 23  
Outlet must be at  
least 45° from  
wall face  
NOTE: The outlet must be positioned so that any  
condensate plume is directed away from adjacent surfaces.  
There must be a constant fall along the entire length of the  
flue system from the outlet back to the boiler.  
45°  
‘Peak’ Uppermost  
45°  
4. It is possible to reduce or increase (with the addition of  
extensions) the length of either or both the 60/100 concentric  
and 60Ø exhaust.  
5. Standard concentric flue extension kits may be added  
between the boiler elbow and the terminal assembly.  
6. The minimum length of the concentric flue is 100mm when  
measured from the edge of the flue elbow.  
500mm Min.  
IMPORTANT: The maximum equivalent length of  
concentric flue is:- 8 metres  
Additional bends may be fitted in the concentric flue, but  
the equivalent length must be reduced by 1 metre (93°  
bend) or 0.5 metres (45° bend).  
Fig. 24  
Air Inlet at Bottom  
7. 60Ø 1 metre extensions (including support bracket), and  
additional 93° & 45° elbows are available. Any additional 93°  
& 45° elbows must be accounted for when calculating flue  
lengths.  
Fig. 25  
NOTE: Permitted positions of the plume outlet relative to  
doors, windows etc. are the same as for conventional  
concentric flues as detailed in the main Installation &  
Servicing Instructions and BS5440 Pt. 1. It is NOT  
necessary to fit a terminal guard over the air inlet or the  
plume outlet.  
24  
© Baxi Heating UK Ltd 2008  
9.0 Plume Displacement  
16  
14  
12  
10  
16  
14  
12  
10  
9.2  
Determining Permissible Lengths  
In the graph the solid line diagonal represents the  
relationship between the concentric flue assembly (and any  
extensions) and the 60Ø exhaust (and any extensions or  
additional bends).  
8
6
4
2
0
8
6
4
2
0
Example 1 - Not Permissible  
If, for instance, a concentric length of 5 metres was required  
and the 60Ø exhaust needed to be 6 metres the graph  
shows that this combination would NOT be permissible as  
the intersection point would be above the solid diagonal line.  
0
2
3
4
5
6
7
8
9
0
2
3
4
5
6
7
8
9
1
1
Concentric 60/100 Flue (metres)Y  
Concentric 60/100 Flue (metres)Y  
Example 1  
Example 2  
Flue Lengths - Not Permissible  
Flue Lengths - OK  
Example 2 - Flue Lengths OK  
16  
14  
12  
10  
Where both lengths have been determined they can be  
applied to the graph to check that the installation is  
permissible. For example, if it was known that 2 metres of  
concentric flue and 4 metres of 60Ø exhaust were required,  
the values could be applied to the graph as shown in  
Example 2.. As the point of intersection of the dotted lines is  
below the solid diagonal line, the combination of lengths is  
shown to be acceptable.  
8
6
4
2
0
Example 3 - Flue Lengths OK  
In the example shown in Fig. 4 assume that the concentric  
part of the flue needs to be 2.3 metres long. Find the  
position of ‘2.3’ on the horizontal axis of the graph and then  
project upwards to the solid diagonal line. This is represented  
by the vertical thick dotted line. Where this dotted line  
intersects with the solid diagonal line on the graph, project  
across to the vertical axis. As can be seen this corresponds  
with 6 metres. Therefore, the total equivalent length of the  
60Ø exhaust can be up to 6 metres. Any bend equivalencies  
must be accounted for i.e. 93° bends are equal to 1 metre,  
each 45° bend to 0.5 metres.  
0
2
3
4
5
6
7
8
9
1
Concentric 60/100 Flue (metres)Y  
Example 3  
Flue Lengths - OK  
Support  
Bracket  
60Ø Exhaust  
X
45° Elbow  
Y
Flue Length - Worked Example  
Potterton Gold Combi 33HE A  
93° Elbow  
In Fig. 27 opposite an additional 93° bend and pair of 45°  
elbows have been included in the 60Ø exhaust.  
Also 3 straight extension pieces have been used.  
1 metre Extension  
Concentric 60/100 Flue  
To calculate total length:-  
1 metre supplied in kit  
Length of 60Ø supplied in kit =  
3 x 1 metre Extensions =  
1 x 93° Elbow =  
1 metre  
Fig. 26  
3 metres  
1 metre  
2 x 45° Elbow =  
1 metre (0.5 metres each)  
Concentric Flue  
Total 60Ø =  
6 metres  
After consulting the table in Example 3 it can be determined  
that the concentric flue could be up to approximately 2.3  
metres long.  
Additional Accessories  
A - 93° Elbow  
B - 45° Elbow (Pair)  
5121369  
5121370  
Fig. 27  
C - 1 metre 60Ø Extension 5121368  
25  
© Baxi Heating UK Ltd 2008  
9.0 Plume Displacement  
9.3  
General Fitting Notes  
1. Cut a hole in the external wall which the concentric flue  
assembly will pass through. The hole should allow the flue  
to fall back to the boiler at an angle of at least 1.5°.  
2. When completed the terminal must be at least 2 metres  
above ground level (Fig. 19).  
3. Measure and cut to size the concentric assembly and any  
extensions that are being used.  
Min. 2 metres  
4. Insert the concentric assembly through the hole from  
outside the building.  
5. If required, the flexible flue trim should be fitted prior to  
this as it cannot be fitted after. Use the large ‘Jubilee’ clip to  
secure the trim to the flue (See Fig. 20, trim shown  
dotted), with the screw part of the clip at the bottom.  
6. Connect any extensions or elbows that are being used  
to the concentric assembly. Engage the extension, elbow  
or concentric assembly in the boiler flue elbow. Fit the  
boiler flue elbow to the boiler adaptor.  
Fig. 28  
Flue Trim  
7. Ensure that the concentric assembly and any extensions  
fall back to the boiler at an angle of at least 1.5° and that  
the external air inlet is to the bottom.  
8. Use suitable brackets to support the concentric  
assembly and any extensions, and make good inside and  
outside.  
Spigot  
9. The 60Ø exhaust can now be fitted. Slide the adaptor  
over the plain end of the 60Ø exhaust (Fig. 22) and engage  
the exhaust in the terminal. Slide the adaptor down over  
the spigot. Mark and drill the adaptor, using a 2mm bit, as  
shown in Fig. 21. Secure the adaptor to the spigot using  
one of the screws supplied.  
Position of ‘Jubilee’ Clip  
screw  
Fig. 29  
50mm  
10. If it is necessary to shorten the 60Ø exhaust or any of  
the extensions, the excess material must be cut from the  
plain end of the pipe.  
Adaptor  
11. Determine the position of the 60Ø exhaust and mark  
on the wall a suitable position for the support bracket. If  
extensions are being used, a support bracket is supplied in  
each kit.  
Fig. 31  
12. Drill the wall, and fit the bracket(s) using the plug and  
screw provided.  
30mm  
Fig. 30  
13. Mark and drill the 60Ø exhaust, using a 2mm bit, as  
shown in Fig. 23. Complete the installation of the 60Ø  
exhaust, securing in the brackets.  
30mm  
14. Fit the 93° elbow/plume outlet and secure with the  
two remaining screws supplied. Ensure the plume outlet is  
at least 45° to the wall and that the ‘peak’ is uppermost  
(Fig. 24).  
Fig. 32  
26  
© Baxi Heating UK Ltd 2008  
Fig. 33  
9.0 Plume Displacement  
Plume Outlet  
Elbow  
9.3  
General Fitting Notes (cont.)  
15. For aesthetic purposes it is permissible to route the  
60Ø exhaust in an enclosed box, but the air inlet and  
plume outlet MUST remain in free air.  
16. It is also possible to separate the plume outlet from the  
93° elbow to allow the flue to be installed as shown in  
Fig. 34.  
17. To do this, first slacken the two screws retaining the  
plume outlet to the elbow, and remove the outlet (Fig. 35).  
The elbow can now be used to connect the vertical to  
horizontal 60Ø exhaust (Fig. 34). Retighten the screws in  
the elbow.  
Fig. 34  
18. The outlet can now be fitted into the female end of an  
60Ø extension piece. It must be secured using two of the  
screws supplied in the bag with the ‘Jubilee’ clip.  
19. Mark the female end of the extension at 30mm as  
shown in two positions, directly opposite each other  
(Fig. 36).  
Fig. 35  
30mm  
20. Using a suitable bit (e.g. 2mm), drill through the  
extension and outlet. Secure using two of the screws  
supplied.  
21. The remaining screw must be used to secure the  
adaptor to the concentric terminal.  
Fig. 36  
22. When the plume outlet is positioned under a balcony  
or other projection (Fig. 37) it must protrude at least  
200mm (it is not necessary to extend it further than this).  
200mm Min.  
23. When under balconies or projections it is permissible to  
rotate the concentric flue length up to 70°, clockwise or  
anti-clockwise (Fig. 38), if there is insufficient space to  
connect vertically.  
24.This will allow the connection of the exhaust to the  
outlet spigot.  
25. All other minimum & maximum dimensions must be  
adhered to, and the air inlet positioned such that it will not  
be subject to rain entry.  
Fig. 37  
70°  
Concentric Flue Length  
(shown end-on)  
Outlet Spigot  
Fig. 38  
27  
© Baxi Heating UK Ltd 2008  
10.0 Installation  
10.1  
Unpacking & Initial Preparation  
The gas supply, gas type and pressure must be checked for  
suitability before connection (see Section 7.4).  
NOTE: a small amount of water may drain from the  
boiler in the upright position.  
1. Remove staples, open flaps and remove the cardboard  
sheet. Remove the polystyrene side pieces and literature.  
Two people can then lift out the boiler (Figs. 39 & 40).  
Fig. 39  
2. After considering the site requirements  
(see Section 7.0) position the fixing template on the wall  
ensuring it is level both horizontally and vertically.  
3. Mark the position of the two most suitable fixing slots for  
the wall plate and boiler lower fixing holes. It is preferable to  
use the vertical fixing slots.  
Fig. 40  
4. Mark the position of the centre of the flue hole (rear  
exit). For side flue exit, mark as shown (Fig. 41).  
5. If required, mark the position of the gas and water pipes.  
Remove the template.  
145mm  
6. Cut the hole for the flue (minimum diameter 116mm).  
7. Drill the wall as previously marked to accept the wall  
plugs supplied. Secure the wall plate using the fixing screws.  
8. Using a spirit level ensure that the plate is level before  
finally tightening the screws.  
For Side Flue Exit  
Fig. 41  
9. Connect the gas and water pipes to the valves on the  
wall plate using the copper tails supplied. Ensure that the  
sealing washers are fitted between the connections.  
Flushing Tube  
10. Fit the filling loop as described in the instructions  
supplied with it.  
Wall Plate  
10.2  
Flushing  
1. Connect a tube to the central heating flow or return pipe  
(Fig. 42 & 43).  
Central Heating Return  
2. Flush thoroughly (see System Details, Section 6.2).  
Fig. 42  
Fig. 43  
28  
© Baxi Heating UK Ltd 2008  
10.0 Installation  
10.3  
Fitting the Filling Loop  
1. The filling loop supplied with the boiler can be  
connected to the taps on the wall plate at this point.  
2. The filling loop is to be connected between the mains  
cold water inlet and central heating return isolation taps.  
Cold Inlet  
3. The loop and valves must be connected as shown in  
the diagram (Fig. 44a).  
4. Note the orientation of the flow direction arrows on  
the stop valve and double check/stop valves.  
Double Check Valve  
& Stop Valve  
Fig. 44a  
5. Remove the end caps from the isolation taps and put  
to one side. Connect the valves to the taps. Ensure that  
the fibre washers supplied are used on these joints.  
Temporary Filling  
Loop  
CH Return  
Stop Valve  
6. Connect the temporary loop, ensuring that the seals  
are fitted.  
To fill, test and flush if required (Fig. 44c)  
7. Take the blanking plugs from the kit, and using washers  
supplied with the boiler, connect them to the central  
heating flow and return taps, and the cold inlet tap. The  
system can now be filled by opening the cold inlet supply  
and stop valves.  
Fitting the Valves  
to the Taps  
8. If desired a suitable gauge can be connected to one of  
the taps so that the system may be accurately  
pressurised.  
Temporary Loop and  
Flanged Washers  
9. All joints, fittings and system components can now be  
examined for soundness at operating pressure.  
10. The system can be flushed by turning off the central  
heating tap and connecting a suitable fitting to the loose  
nut. From the fitting a hose pipe can be run to the  
nearest convenient drain. When the tap is reopened the  
system will flush.  
Fig. 44b  
11. Remove the blanking plug(s), pressure gauge and  
flushing equipment from the appliance if used.  
12. Continue with the installation and commissioning.  
13. The filling loop must be disconnected and completely  
removed after the system is pressurised.  
Pressure  
Gauge  
14. Hand tighten the two previously removed end caps  
to the stop valve and double check valve.  
Blanking  
Plugs  
Hose and  
Fitting  
Fig. 44c  
29  
© Baxi Heating UK Ltd 2008  
10.0 Installation  
Wall Plate  
10.4  
Fitting The Boiler  
1. Lift the boiler using the Lifting Points as shown by the  
shaded areas (Fig. 45). The boiler should be lifted by TWO  
PEOPLE. Engage the slots at the top rear of the boiler on the  
wall plate (Fig. 46) (see Safe Manual Handling page 5).  
2. Ease the boiler forwards and remove the sealing caps from  
the boiler connections.  
NOTE: A small amount of water may drain from the boiler  
once the caps are removed.  
3. Insert the sealing washers between the valves and pipes on  
the wall plate and the boiler connections. THE RUBBER  
WASHERS MUST BE USED ON THE GAS CONNECTION.  
Fig. 46  
4. Tighten all the connections.  
Fig. 45  
Suggested Lifting Points  
shown as shaded area  
10.5  
Fitting the Pressure Relief Discharge Pipe  
(Fig. 47)  
1. Remove the discharge pipe from the kit.  
2. Determine the routing of the discharge pipe in the vicinity of  
the boiler. Make up as much of the pipework as is practical,  
including the discharge pipe supplied.  
3. The pipework must be at least 15mm diameter and run  
continuously downwards to a discharge point outside the  
building. See section 6.7 for further details.  
4. Utilising one of the sealing washers, connect the discharge  
pipe to the adaptor and tighten the nut.  
5. Complete the discharge pipework and route it to the  
outside discharge point.  
Pressure Relief Valve  
IMPORTANT: Make all soldered joints before connecting  
to the pressure relief valve.  
10.6  
Condensate Drain (see section 7.7)  
Fig. 47  
1. Connect the condensate drain to the trap outlet pipe.  
Ensure the discharge of condensate complies with any  
national or local regulations in force (see British Gas  
“Guidance Notes for the Installation of Domestic Gas  
Condensing Boilers”.  
Discharge Pipe  
3
2. The connection will accept 21.5mm ( /4in) plastic overflow  
pipe which should generally discharge internally into the  
household drainage system. If this is not possible, discharge into  
an outside drain is acceptable.  
30  
© Baxi Heating UK Ltd 2008  
10.0 Installation  
10.7  
Fitting The Flue  
HORIZONTAL FLUE  
1. The standard flue is suitable for lengths between 100mm  
minimum and 685mm maximum, as measured from the  
edge of the flue elbow outlet to the joint between the  
terminal and air duct (Fig. 48).  
Fig. 48  
2. Locate the flue elbow on the adaptor at the top of the  
boiler. Set the elbow to the required orientation (Fig. 50).  
The elbow is fully engaged when there is a distance of  
20mm from the adaptor to the indicator line (Fig. 49).  
20mm  
NOTE: The flue elbow is angled at 93 degrees to  
ensure a fall back to the boiler.  
Wall Thickness  
Indicator line  
3. Measure the distance from the outside wall face to the  
elbow. This dimension will be known as ‘X’ (Fig. 51).  
Fig. 49  
Flue Elbow  
4. To dimension ‘X’ add 50mm. This dimension to be  
known as ‘Y’.  
(X)  
Apply Lubricant for  
ease of assembly.  
IMPORTANT: Check all dimensions before cutting.  
Ensure Elbow is fully  
engaged into Boiler  
Adaptor  
Adaptor  
5. Mark dimension ‘Y’ on the flue as shown (Fig. 52).  
Carefully cut the waste material from the flue, ensuring that  
the ducts are square and free from burrs.  
Fig. 50  
Wall Thickness  
(X)  
Fig. 51  
Waste  
Y
Flue  
Fig. 52  
31  
© Baxi Heating UK Ltd 2008  
10.0 Installation  
Inner Flue Support Bracket  
10.7  
Fitting the Flue (Cont)  
6. The inner flue duct support bracket may be in the waste  
portion of the flue. In this case retrieve the bracket before  
discarding the waste.  
7. Take the inner flue support bracket (if not already fitted)  
and engage it over the flue duct. This will centralise the flue  
and air ducts, and ease assembly (Fig. 53).  
Fig. 53  
8. Insert the flue through the hole in the wall. Fit the elbow  
to the boiler adaptor, ensuring that it is pushed fully in.  
Apply Lubricant for  
ease of assembly.  
Ensure Flue is fully  
engaged into Flue  
Elbow  
9. Draw the flue back through the wall and engage it in the  
elbow. It may be necessary to use soap solution or similar  
to ease assembly of the elbow adaptor and flue (Fig. 54).  
10. Ensure that the terminal is positioned with the slots to  
the bottom (Fig. 55).  
IMPORTANT: It is essential that the flue terminal is fitted  
as shown to ensure correct boiler operation and prevent  
water entering the flue.  
11. Make good between the wall and air duct outside the  
building.  
12. Fit the flue trim if required, and if necessary fit a terminal  
guard (see Section 8.8 & 8.9).  
Slots at bottom  
Fig. 55  
CONCENTRIC VERTICAL FLUE  
13. Once the length of the vertical concentric extension has  
been determined mark and carefully cut off the excess  
material. The cut end MUST be square and free of burrs to  
ensure correct insertion into the boiler adaptor.  
Fig. 54  
25mm  
14. Measure 25mm from the end of the flue extension and  
apply a length of tape around the outer duct (Fig. 56).  
15. Engage the extension into the adaptor up to this  
position (Fig. 57). Once the installation of the flue is  
complete and all support brackets are securely in place  
remove the tape.  
Extension  
Fig. 56  
Tape  
Cut End  
Adaptor  
Apply Lubricant for  
ease of assembly.  
Ensure Extension is  
fully engaged into  
Boiler Adaptor  
Fig. 57  
32  
© Baxi Heating UK Ltd 2008  
10.0 Installation  
10.8  
Making The Electrical Connections  
The boiler is fitted with a 1.3m length of 3 core cable. This  
can be connected to the fused 3A 230V 50HZ supply.  
NOTE: Both the Live and Neutral connections are fused.  
To connect an external control proceed as follows:-  
Terminal Block Cover  
1. Slacken the facia panel securing screws and lift the  
outercase panel so that its securing tabs are clear of the  
facia. Remove the panel.  
2. Completely undo the screws securing the facia panel and  
hinge it down (Fig. 58).  
3. Undo the terminal block cover securing screw and  
remove the cover (Fig. 58).  
Fig. 58  
4. Slacken the unused cable clamp on the LH side of the  
boiler chassis (Fig. 59). Insert the external control wiring  
through the clamp and route it to the terminal block.  
Fig. 59  
Facia Panel  
Cable Clamp  
5. Refer to the instructions supplied with the control.  
IMPORTANT: The room thermostat MUST be suitable  
Fused Spur  
for 230V switching.  
L
N
Room ‘Stat  
N
NOTE: An external frost thermostat cannot be used  
with the optional integral timer.  
6. Remove the link between terminals 1 & 2. The 230V  
supply at terminal 2 must be connected to the thermostat.  
The switched output from the thermostat must be  
connected to terminal 1 (Figs. 60 & 61). If the room  
thermostat being used incorporates an anticipator it MUST  
be wired as shown in Figs. 60 & 61.  
bk  
bk  
1
2
230V  
g/y  
b
N
L
7. Ensure that the external control input cable(s) have  
sufficient slack to allow the control box to drop down.  
Tighten the cable clamp on the boiler chassis.  
br  
Fig. 60  
8. Replace the terminal block cover, routing the external  
control input cable(s) through the second cut-out.  
Frost Thermostat  
Fused Spur  
L
N
Room ‘Stat  
10.9  
Preliminary Electrical Checks  
230V  
N
1. Prior to commissioning the boiler preliminary electrical  
system checks should be carried out.  
bk  
bk  
1
2
230V  
2. These should be performed using a suitable meter, and  
include checks for Earth Continuity,  
External Clock  
g/y  
Resistance to Earth, Short Circuit and Polarity.  
b
N
L
br  
Fig. 61  
NOTE: The 230V switched signal for external controls  
(Frost Stat - Room Stat - Timer) must always be taken  
from terminal 2 at the boiler. Live, Neutral and Earth to  
power these controls must be taken from the Fused Spur.  
33  
© Baxi Heating UK Ltd 2008  
Heat Exchanger  
Automatic Air Vent  
11.0 Commissioning  
Fig. 62  
11.1  
Commissioning the Boiler  
1. Reference should be made to BS 5449 Section 5 when  
commissioning the boiler.  
2. Open the mains water supply to the boiler.  
IMPORTANT: The heat exchanger air vent on top of the  
boiler (Fig. 62) MUST be opened before filling the  
primary system.  
Screw  
3. Open all hot water taps to purge the DHW system.  
Pump  
Automatic Air  
Vent  
4. Ensure that the filling loop is connected and open, then  
open the heating flow and return valves on the boiler.  
5. Open the screw on the automatic air vent on the pump  
body (Fig. 63).  
6. The system must be flushed in accordance with BS 7593  
(see Section 6.2) and the flushing agent manufacturers  
instructions.  
7. Pressurise the system to 1.5 bar (Fig. 64) then close and  
disconnect the filling loop.  
2
Pump  
Fig. 63  
1
3
8. Turn the gas supply on and purge according to in GB BS  
6891 and in IE I.S. 813 “Domestic Gas Installations”.  
0
4
bar  
Selector Switch  
Display  
Pressure Gauge  
Fig. 64  
9. Test for gas soundness.  
10. Hinge the facia panel upwards and refit the case front  
panel. Tighten the securing screws.  
2
Reset  
3
11. Turning either of the temperature control knobs will set  
the relevant temperature. When the knob is turned the  
display will alter and show the selected temperature. After a  
few seconds the display reverts to show the current boiler  
temperature (Fig. 65).  
0
4
0
bar  
Central Heating  
Temperature Control  
Domestic Hot Water  
Temperature Control  
Fig. 65  
34  
© Baxi Heating UK Ltd 2008  
11.0 Commissioning  
11.2  
Checking  
1. The gas valve is factory set and the burner pressure cannot  
be measured as it is altered by suction of the fan and  
modulates as demand on the boiler alters. The gas supply  
pressure should be 20mb.  
x 2  
2. If necessary the gas rate may be checked after running the  
boiler for 10 minutes with any other appliances and pilot  
lights turned off.  
3. Ensure that the integral timer and any external controls are  
calling for heat, and the selector switch is in the central  
Central Heating  
Temperature Control  
Domestic Hot Water  
Temperature Control  
heating and hot water position (  
). The current boiler  
Fig. 66  
temperature is shown on the display.  
4. To check the gas rate it is necessary to set the boiler to  
‘Calibration Mode’.  
Display  
Selector Switch  
5. Turn both temperature control knobs fully anticlockwise,  
1
then quickly turn the DHW temperature knob /4 clockwise  
twice and back fully anticlockwise (Fig. 66).  
2
Reset  
3
6. The display will now alternate between ‘SF’ and the  
current boiler temperature and both green LEDs will flash  
(Figs. 67 & 68).  
0
4
0
bar  
Central Heating  
Temperature Control  
Domestic Hot Water  
Temperature Control  
7. Turn CH temperature control knob fully clockwise. As the  
knob is turned the display will change from ‘0’ to ‘00’ (Fig. 69)  
indicating maximum rate, then revert to ‘P’ alternating with  
the current boiler temperature (Figs 70 & 71).  
8. A gas rate measurement may now be made. Approximate  
values are:-  
3
24 model  
28 model  
33 model  
2.6m /h  
3
3.1m /h  
3
3.6 m /h  
9. The ‘Calibration Function’ is active for 20 minutes unless  
the maximum CH temperature is exceeded.  
Fig. 67  
Fig. 68  
10. The function can be disabled at any time by turning the  
DHW temperature knob.  
Fig. 69  
Fig. 71  
Fig. 70  
35  
© Baxi Heating UK Ltd 2008  
11.0 Commissioning  
11.3  
Setting the Timer  
The Electro-Mechanical Timer allows the central heating  
system to be set every 15 minutes.  
Time Pointer  
Using the three position switch the timer will allow either  
constant operation, timed operation or central heating off.  
Constant  
Timed  
Off  
Move the switch button by sliding to the desired position.  
Three position switch (Fig. 71a)  
Constant (Top position): The heating will be on  
constantly irrespective of the position of the tappets.The  
heating will be controlled by the main thermostat on the  
appliance and/or any external controls.  
0
IN  
Timed (Central position): The heating will operate  
according to the position of the tappets and be controlled as  
above.  
Fig. 71a  
Rotate to adjust time  
0
Off (Bottom position): No central heating.  
Domestic hot water will operate on demand.  
To set the time of day  
Turn the timer outer bezel clockwise, to align the pointer  
with the correct time to the nearest 15 minutes  
ensuring that A.M./P.M. is considered. Do not at any time  
attempt to turn the bezel anti-clockwise.  
To set the timed heating program  
Decide which times of the day the central heating is required.  
0
The heating will operate when the white tappets are set to  
the outer edge of the bezel.  
To ensure the heating stays OFF set the required tappets  
inwards towards the centre of the bezel.  
Each tappet represents 15 minutes.  
For example: If the heating is not required between  
10 A.M. and 11 A.M. the four tappets anticlockwise from the  
10 A.M. will be set inwards (Fig. 71b).  
On Position  
Off Position  
Time Pointer  
Fig. 71b  
36  
© Baxi Heating UK Ltd 2008  
12.0 Completion  
12.1  
Completion  
Case Front Panel  
1. Instruct the user in the operation of the boiler and  
system explaining the operational sequence.  
2. Set the central heating and hot water temperature  
control knobs to the requirements of the user.  
3. Carefully read and complete all sections of the  
Benchmark Commissioning Checklist at the rear of this  
publication that are relevant to the appliance and  
installation. These details will be required in the event of  
any warranty work. The publication must be handed to the  
user for safe keeping and each subsequent regular service  
visit recorded.  
4. For IE, it is necessary to complete a “Declaration of  
Conformity” to indicate compliance with I.S. 813. An  
example of this is given in I.S. 813 “Domestic Gas  
Installations”. This is in addition to the Benchmark  
Commissioning Checklist.  
5. Hand over the Users Operating, Installation and  
Servicing Instructions giving advice on the necessity of  
regular servicing.  
Facia Panel  
Fig. 72  
37  
© Baxi Heating UK Ltd 2008  
13.0 Servicing  
13 .1 Annual Servicing  
Case Front Panel  
1. For reasons of safety and economy, it is recommended that  
the boiler is serviced annually. Servicing must be performed by  
a competent person in accordance with B.S. 7967-4:2007.  
If a suitably calibrated combustion analyser is available it  
may not be necessary to perform a full strip down of the  
appliance. Proceed as follows.  
Check for/inspect:-  
Evidence of leakage of products of combustion  
Water leaks  
Heat stress  
Deterioration such as corrosion  
Visible condition of seals and joints  
Flue system and ventilation  
Condensate drain system  
Operation at designed maximum heat input  
Fig. 73  
If the above are satisfactory perform a combustion check  
The CO/CO2 ratio must be less than 0.004 and the CO2  
should be 8.7% 0.2 (max. rate) and 8.4% 0.2 (min.  
rate). This can be adjusted - see Section 15.0 - if the  
readings are incorrect. When correct combustion  
readings cannot be achieved by adjustment a full strip  
down must be performed - see below. Carefully check  
items such as the burner, injector and heat exchanger  
for blockage or damage, rectifying as necessary. Re-  
check the combustion. Once satisfactory readings have  
been achieved and any other defects corrected complete  
the relevant Service Interval Record section of the  
Benchmark Commissioning Checklist at the rear of this  
publication.  
Facia Panel Securing  
Screws  
Where no suitable analyser is available a strip down  
service must be performed as described below.  
2. After servicing, complete the relevant Service Interval  
Record section of the Benchmark Commissioning Checklist at  
the rear of this publication.  
If a full strip-down is to be performed proceed as follows:-  
3. Ensure that the boiler is cool.  
4. Ensure that both the gas and electrical supplies to the  
boiler are isolated.  
Inner Door  
Panel  
Fig. 74  
5. Slacken the screws securing the facia panel. Lift the  
outercase panel so that its securing tabs are clear of the facia.  
Remove the panel, allowing the facia to hinge down (Fig. 73).  
6. Remove the screws securing the inner door panel. Lift the  
panel slightly to disengage it from the studs on top of the case  
(Fig. 74).  
7. Unscrew the sump from the bottom of the condensate trap  
assembly (Fig. 75).  
Sump  
8. Remove any deposits from the sump and trap. Clean as  
necessary and replace the sump.  
Fig. 75  
38  
© Baxi Heating UK Ltd 2008  
13.0 Servicing  
Burner  
Viewing Window  
13.1  
Annual Servicing (Cont)  
7.5  
1
9. Undo the nut on the gas inlet pipe to the venturi (Fig. 77)  
and pull the sensing pipe off the fan.  
4
0.5  
10. Disconnect the electrode leads, noting their position,  
and the fan electrical plugs.  
11. Undo the four nuts retaining the combustion box cover  
to the heat exchanger.  
12. Carefully draw the fan, collector and cover assembly  
forward, being careful to retain the injector in the venturi  
(Figs. 76 & 77).  
10  
1
Electrode Position  
13. Clean any debris from the heat exchanger and check  
that the gaps between the tubes are clear.  
Fan, Collector and Cover  
Assembly  
14. Inspect the burner, electrodes and insulation, cleaning or  
replacing if necessary. Clean any dirt or dust from the air  
box.  
15. Reassemble in reverse order.  
NOTE: The sensing pipe must be reconnected to the  
fan, not the venturi.  
Electrode  
Leads  
DHW Filter (Fig. 79)  
16. If the flow of domestic hot water is diminished, it may  
be necessary to clean the filter.  
Fig. 76  
17. Initially check the cold water inlet tap filter.  
Venturi  
18. Turn the tap off and draw off from a hot tap. Undo the  
blanking cap and remove the threaded bush (Fig. 78).  
19. Extract the filter and rinse thoroughly in clean water.  
Reassemble and check the flow. If required clean the  
restricter filter as described below.  
Injector  
Fig. 78  
Threaded  
Bush  
20. Pull off the Hall Effect sensor. Undo the restricter from  
the inlet/return manifold (Fig. 79).  
21. Rinse the filter thoroughly in clean water and reassemble  
in reverse order.  
Gas Inlet Pipe  
Fig. 77  
22. Turn the selector switch fully anticlockwise against the  
spring pressure to the reset position and hold for 5 seconds  
to reset the boiler.  
Hall Effect  
Sensor  
Blanking  
Cap  
Cold Water  
Inlet Tap  
23. Complete the relevant Service Interval Record section of  
the Benchmark Commissioning Checklist at the rear of this  
publication and then hand it back to the user.  
Restricter  
Hydraulic Inlet  
Assembly  
Fig. 79  
Filter  
39  
© Baxi Heating UK Ltd 2008  
14.0 Changing Components  
IMPORTANT: When changing components ensure that  
both the gas and electrical supplies to the boiler are  
isolated before any work is started. When the  
component has been changed turn the selector switch  
fully anticlockwise against the spring pressure to the  
reset position and hold for 5 seconds to reset the boiler  
before recommissioning.  
Bracket  
Igniter  
Igniter Feed  
Plug  
See Section 13.1 “Annual Servicing” for removal of case  
panel, door etc.  
Electrode  
Leads  
14.1  
Igniter (Fig. 80)  
1. Disconnect the igniter feed plug and the electrode leads,  
noting their positions.  
Fig. 80  
2. Undo the screw securing the bracket to the boiler.  
3. Remove the igniter and transfer the bracket to the new  
component.  
4. Reassemble in reverse order.  
14.2  
Spark and Sensing Electrodes (Fig. 81)  
1. Disconnect the electrode leads, noting their positions.  
2. Remove the retaining screws securing each of the  
electrodes to the combustion box cover and remove the  
electrodes.  
3. Check the condition of the sealing gasket and replace if  
necessary. Reassemble in reverse order.  
Spark  
Electrode  
Electrode  
Leads  
Sensing  
Electrode  
Fig. 81  
40  
© Baxi Heating UK Ltd 2008  
14.0 Changing Components  
14.3  
Fan (Fig. 83)  
1. Undo the nut on the gas inlet pipe to the venturi (Fig. 83)  
and pull the sensing pipe off the fan.  
2. Disconnect the electrode leads, noting their position and  
disconnect the fan electrical plugs.  
3. Undo the screws securing the collector to the cover (33  
models) or extension piece (24 & 28 models).  
4. Remove the collector and fan assembly, being careful to  
retain the injector in the venturi.  
5. Undo the screws securing the fan to the venturi and fit the  
new fan, replacing the seal if necessary.  
6. Examine the burner gasket and replace if necessary.  
Venturi  
Injector  
7. Reassemble in reverse order, ensuring that the injector is  
in place and the sensing pipe is connected to the fan.  
14.4  
Venturi (Fig. 82)  
Cover  
1. Remove the collector and fan assembly as described in  
section 14.3.  
2. Extract the injector from the venturi.  
Gas Inlet Pipe  
Fig. 83  
3. Undo the screws securing the fan to the venturi and the  
venturi to the collector.  
Burner  
Gasket  
IMPORTANT: When fitting the new venturi, ensure the  
arrows on it’s base point into the collector (Fig. 84).  
4. Examine the seals and burner gasket, replace if necessary.  
Gas Inlet  
5. Reassemble in reverse order, ensuring that the injector is  
in place.  
Fan  
14.5  
Injector (Fig. 82)  
Venturi  
Injector  
1. Remove the collector and fan assembly as described in  
section 14.3.  
Collector  
Fig. 82  
2. Extract and replace the injector and reassemble in reverse  
order.  
Fig. 84  
When fitting the venturi  
ensure that the arrow is  
pointing forward  
41  
© Baxi Heating UK Ltd 2008  
14.0 Changing Components  
Cover  
14.6  
Burner (Fig. 85)  
Burner  
1. Undo the screws securing the collector to the cover and  
venturi. (On 24 & 28 models there is an extension piece  
fitted to the cover, remove this also).  
Gasket  
Extension Piece  
(24 & 28 models)  
2. Withdraw the burner from the cover and replace with  
the new one.  
3. Examine the gasket, replacing if necessary.  
4. Reassemble in reverse order.  
Venturi  
14.7  
Insulation (Fig. 86)  
1. Remove the electrode leads, noting their positions. Also  
remove the electrodes as described in section 14.2.  
Collector  
Fig. 85  
2. Undo the screws securing the collector to the venturi and  
the nuts holding the cover to the heat exchanger. Draw the  
collector and cover assembly away.  
3. Remove the cover insulation piece.  
4. Fit the new insulation carefully over the burner and align  
it with the slots for the electrodes.  
5. The rear insulation is retained by a screw and large  
washer, remove these and draw the insulation out of the  
heat exchanger.  
6. Examine the cover seal and replace if necessary.  
Heat  
Exchanger  
Rear  
Insulation  
Spark  
Electrode  
Venturi  
Cover  
Insulation  
Seal  
Fig. 86  
Collector  
Electrode  
Leads  
Sensing  
Electrode  
42  
© Baxi Heating UK Ltd 2008  
14.0 Changing Components  
Electrical  
Plug  
14.8  
Flue/Heat Exchanger Thermostat Sensor  
(Fig. 87)  
Flue/Heat Exchanger  
Thermostat Sensor  
1. Ease the retaining tab on the sensor away and disconnect  
the electrical plug.  
°
2. Turn the sensor 90 anticlockwise to remove - it is a  
bayonet connection.  
3. Reassemble in reverse order.  
Fig. 87  
14.9  
Water Pressure Sensor (Fig. 89)  
1. Drain the primary circuit.  
2. Disconnect the two wires from the sensor.  
3. Undo the nut on the flow pipe securing and sealing the  
sensor.  
4. Remove the sensor, examine the sealing washer, replacing if  
necessary.  
5. Reassemble in reverse order. The component is not  
polarised - either wire will fit each terminal.  
14.10 Central Heating Temperature Sensor (NTC)  
(Fig. 88)  
Flow Pipe  
Central Heating  
Temperature Sensor  
1. Ease the retaining tab on the sensor away and disconnect  
the electrical plug.  
2. Unscrew the sensor from it’s pocket and reassemble in  
reverse order. The plug will only fit one way.  
14.11 Safety Thermostat (Fig. 88)  
1. Pull the plug off the thermostat.  
Safety Thermostat  
2. Remove the screws securing the thermostat to the  
mounting plate on the flow pipe.  
3. Reassemble in reverse order, ensuring that the plug is  
pushed fully on.  
Fig. 88  
14.12 DHW Temperature Sensor (NTC) (Fig. 89)  
1. Turn off the mains cold water supply tap and draw off the  
residual domestic hot water.  
Pressure Sensor  
Plate Heat  
Exchanger  
2. Ease the retaining tab on the sensor away and disconnect  
the electrical plug.  
3. Unscrew the sensor from the plate heat exchanger  
manifold. Examine the sealing washer,replacing if necessary.  
4. Reassemble in reverse order. The plug will only fit one way.  
Fig. 89  
DHW Temperature  
Sensor  
43  
© Baxi Heating UK Ltd 2008  
14.0 Changing Components  
Heat Exchanger  
Air Vent  
14.11 Heat Exchanger Automatic Air Vent (Fig. 90)  
1. Drain the boiler primary circuit and unscrew the  
automatic air vent from the pump body.  
2. Examine the ‘O’ ring seal, replacing if necessary, and fit it  
to the new automatic air vent.  
Grommet  
3. Reassemble in reverse order, transferring the grommet to  
the new vent.  
4. Ensure that the grommet is is sealed correctly to the  
boiler top panel.  
Fig. 90  
14.12 Pump - Head Only (Fig. 91)  
1. Drain the boiler primary circuit and remove the socket  
head screws securing the pump head to the body and draw  
the head away.  
2. Undo the screw on the pump wiring cover and remove  
the cover. Using a suitable flat bladed screw driver press the  
cable securing levers downwards to release each wire after  
noting their position.  
Pump Wiring  
Pump Body  
Cover  
3. A standard replacement Grundfos 15-60 head can now  
be fitted. Connect the pump wiring to the new head. The  
pump speed must be set to 3 (Fig. 92).  
4. Reassemble in reverse order.  
Socket Headed  
Screw  
14.13 Pump - Complete (Fig. 93)  
1. Drain the boiler primary circuit.  
Pump Head  
2. Undo the two screws securing the body to the pipe and  
manifold and draw the pump forwards.  
Fig. 91  
3. Undo the screw on the pump wiring cover and remove  
the cover. Using a suitable flat bladed screw driver press the  
cable securing levers downwards to release each wire after  
noting their position.  
Pump Setting  
4. Unscrew the automatic air vent from the pump body.  
Fig. 92  
Automatic Air  
Vent  
5. Connect the wiring to the new pump. Examine the ‘O’  
ring seals on the return pipe and manifold, replacing if  
necessary.  
Pump Wiring  
Cover  
6. Fit the air vent to the pump body and reassemble in  
reverse order.  
14.14 Automatic Air Vent (Fig. 93)  
1. Drain the boiler primary circuit and unscrew the  
automatic air vent from the pump body.  
2. Examine the ‘O’ ring seal, replacing if necessary, and fit it  
to the new automatic air vent.  
Fig. 93  
3. Reassemble in reverse order.  
44  
© Baxi Heating UK Ltd 2008  
14.0 Changing Components  
14.15 Pressure Gauge (Figs. 94 & 95)  
Gauge Retaining  
Bracket  
1. Drain the boiler primary circuit and undo the nut on the  
pressure gauge capillary.  
2. Undo the screws securing the gauge retaining bracket.  
3. Remove the bracket and gauge assembly. Depress the  
barbs on the side of the gauge and remove the retaining  
bracket.  
Pressure Gauge  
Fig. 94  
4. Examine the sealing washer, replace if necessary.  
5. Reassemble in reverse order.  
14.16 Hall Effect Sensor (Fig. 96)  
1. Ease the sensor upwards off the hydraulic inlet manifold  
assembly.  
2. Disconnect the electrical plug from the sensor.  
3. Connect the plug to the new sensor. Carefully fit the new  
sensor to the hydraulic assembly, ensuring it is fully down.  
Fig. 95  
Pressure Gauge  
Capillary  
Hall Effect  
Sensor  
14.17 Pressure Relief Valve (Fig. 97)  
1. Drain the boiler primary circuit.  
2. Disconnect the discharge pipe from the valve. Using a  
suitable hexagon key undo the grub screw sufficiently to  
release the valve.  
3. Note the orientation of the valve, rotate it and withdraw  
it from the manifold.  
Hydraulic Inlet  
Assembly  
4. Fit the new valve and ‘O’ ring seal and set to the  
previously noted orientation. Reassemble in reverse order.  
Fig. 96  
‘O’ ring seal  
Grub Screw  
Pressure Relief Valve  
Fig. 97  
Discharge Pipe  
45  
© Baxi Heating UK Ltd 2008  
14.0 Changing Components  
14.18 Plate Heat Exchanger (Fig. 98)  
1. Drain the boiler primary circuit and remove the gas valve  
as described in section 13.22.  
Plate Heat Exchanger  
2. While supporting the heat exchanger undo the screws  
securing it to the brass manifolds.  
3. Withdraw the heat exchanger upwards, taking care not to  
damage any wires or controls.  
Seals  
4. There are four rubber seals between the manifolds and  
heat exchanger which may need replacement.  
LH Location Stud  
Fig. 98  
5. Ease the seals out of the manifold. Replace carefully,  
ensuring that when the seal is inserted into the manifold it is  
parallel and pushed fully in.  
Rubber Seal  
6. When fitting the new heat exchanger note that the left  
hand location stud is offset towards the centre more than the  
right hand one.  
7. Reassemble in reverse order.  
14.19 Diverter Valve - Motor Unit & Assembly  
(Figs. 99 & 100)  
1. To replace the motor unit, disconnect the multi-pin plug.  
2. Pull off the retaining clip and remove the motor unit.  
Motor Unit  
3. The motor unit can now be replaced, or the valve  
assembly removed.  
Multi-pin Plug  
4. Drain the primary circuit and draw off any hot water once  
the isolating taps are closed.  
Retaining Clip  
5. Remove the spring clip retaining the bypass pipe to the  
rear of the assembly and under the flow pipe nut at the left  
hand side.  
Valve  
Assembly  
6. Undo the nuts on the tap rail under the boiler. Remove  
the screws securing the valve assembly to the boiler bottom  
panel and plate heat exchanger.  
Fig. 99  
7. Remove the valve assembly. Examine any seals or washers,  
replacing if necessary. Transfer the DHW NTC to the new  
valve and reassemble in reverse order.  
Pressure Sensor  
Bypass Pipe  
Spring Clip  
Fig. 100  
Securing Screw  
46  
© Baxi Heating UK Ltd 2008  
14.0 Changing Components  
14.20  
P.C.B. (Fig. 102)  
1. Note the settings of the temperature control knobs,  
rotate them fully anticlockwise and carefully pull them off  
the drive pins.  
2. Completely undo the screws securing the control box  
cover and release the cover retaining barbs from their slots.  
Disengage the rear of the cover from the control box hinge  
pin (Fig. 101).  
3. Note the position of all plugs and wires on the P.C.B. and  
disconnect them.  
4. Undo the securing screws and remove the P.C.B. Transfer  
the control knob drive pins to the new P.C.B. and turn them  
fully anticlockwise.  
Control Box Cover  
P.C.B.  
Fig. 101  
5. Reassemble in reverse order, ensuring that the  
temperature controllers are reset to their previous positions.  
14.21 Selector Switch (Fig. 102)  
Selector  
Switch  
1. Note the setting of the selector switch knob and carefully  
pull it off the facia.  
Drive Pins  
2. Completely undo the screws securing the control box  
cover and release the cover retaining barbs from their slots.  
Disengage the rear of the cover from the control box hinge  
pin (Fig. 101).  
3. Note the position of the electrical connections and the  
orientation of the switch. Remove the electrical connections.  
4. Remove the screws securing the switch to the facia panel.  
Facia  
5. Fit the new switch, ensuring that it is correctly positioned  
and reassemble in reverse order.  
Selector Switch Knob  
Temperature Control Knobs  
Fig. 102  
47  
© Baxi Heating UK Ltd 2008  
Venturi Inlet  
Pipe  
14.0 Changing Components  
Outlet Adaptor  
14.23 Gas Valve (Fig. 103)  
IMPORTANT: After replacing the valve the CO2 must be  
checked and adjusted as detailed in Section 15.0  
Combustion Check. Only change the valve if a suitable  
calibrated combustion analyser is available.  
Gas Valve  
Sensing Pipe  
Ignition Lead  
1. Turn the gas cock off and undo the nut on the gas feed  
elbow under the boiler.  
2. Remove the screws securing the inlet pipe flange to the  
boiler bottom panel.  
3. Pull off the earth lead and sensing pipe.  
4. Undo the nut on the venturi inlet pipe and slacken the nut  
on the venturi. Ease the pipe aside and remove the gas valve.  
Valve  
Inlet Pipe  
5. Remove the outlet adaptor and inlet pipe and transfer them  
to the new valve. Examine the ‘O’ ring seals, replace if  
necessary.  
Gas Feed  
Elbow  
Fig. 103  
6. Reassemble in reverse order.  
NOTE: To assist the boiler to light prior to final setting,  
use a suitable hexagon key to wind out the Gas/Air  
adjustment screw until it is flush with the valve body, then  
turn the screw 4 full turns clockwise (Fig. 103a). If the  
boiler will not light, or the correct CO2 cannot be achieved  
contact the ‘heateam’ technical helpline.  
Gas/Air  
Adjustment Screw  
14.24 Expansion Vessel (Fig. 104)  
1. Drain the primary circuit and undo the nut on the vessel  
connection pipe.  
Fig. 103a  
2. Undo and remove the locknut securing the vessel spigot to  
the boiler air box.  
Retaining Bracket  
3. Remove the bracket and vessel from the boiler.  
Expansion Vessel  
4. Locate the retaining bracket on the upper flange of the  
vessel and fit to the boiler.  
5. Reassemble in reverse order.  
Lock Nut  
Boiler Chassis  
Fig. 104  
48  
© Baxi Heating UK Ltd 2008  
15.0 Combustion Check  
15.1  
Checking the CO2  
x 2  
IMPORTANT: The CO2 must only be checked and  
adjusted if a suitable calibrated combustion analyser is  
available.  
1. The combustion (CO2) may be checked using a suitably  
calibrated analyser after running the boiler for several  
minutes.  
Central Heating  
Temperature Control  
2. To do this it is necessary to set the boiler to ‘Calibration  
Mode’.  
Domestic Hot Water  
Temperature Control  
Fig. 105  
Display  
Selector Switch  
3. Ensure that all external controls are calling for heat. The  
actual current boiler temperature is shown on the display.  
4. Turn both temperature control knobs fully anticlockwise,  
1
2
then quickly turn the DHW temperature knob /4 clockwise  
Reset  
3
twice and back fully anticlockwise (Fig. 105).  
0
4
0
bar  
5. The display will now alternate between ‘SF’ and the  
current boiler temperature and both green LEDs will flash  
(Figs. 106 & 107).  
Central Heating  
Temperature Control  
Domestic Hot Water  
Temperature Control  
6. Turn the CH temperature knob fully clockwise. As the  
knob is turned the display will change, indicating the fan  
speed.  
7. The display will show ‘00’, indicating maximum rate, then  
revert to ‘P ‘ alternating with the current boiler temperature  
(Figs 108, 109 & 110).  
Fig. 107  
Fig. 106  
8. Remove the plug from the flue adaptor test point. Insert  
the analyser probe and allow time for the reading to settle  
(Fig. 111).  
The CO2 should be 8.7% 0.2  
9. It is possible to alter the CO2 by adjustment of the gas  
valve. Remove the plastic cover from the ‘Max Rate’  
adjustment screw. At maximum rate the ‘Max. Rate’  
adjustment screw should be turned, using a suitable  
hexagon key, until the correct reading is obtained (Fig. 112).  
Turning clockwise will reduce the CO2. Anticlockwise will  
increase the CO2.  
Fig. 109  
Fig. 110  
Fig. 108  
Flue Adaptor Test  
Point  
Plug  
10. The CO2 must then be checked at minimum rate. Turn  
the CH temperature knob fully anticlockwise. As the knob is  
turned the display will change, indicating the fan speed.  
When the display reads ‘ 0’ the boiler runs at minimum rate.  
The CO2 should be 8.4% 0.2.  
Analyser Probe  
Fig. 111  
Max Rate  
Adjustment Screw  
(cover removed)  
Min Rate  
Adjustment Screw  
(cap fitted)  
11. With the boiler on minimum, the ‘Min. Rate’ adjustment  
screw must be altered, using a suitable hexagon key, after  
removing the cap (Fig. 112). If the CO2 is reset at either  
boiler rate it must be rechecked at the other rate and also  
adjusted if required.  
12. The ‘Calibration Function’ is maintained for 20 minutes  
unless the maximum CH temperature is exceeded. The  
function can be disabled at any time by turning the DHW  
knob.  
Gas Valve  
Fig. 112  
49  
© Baxi Heating UK Ltd 2008  
16.0 Electrical  
16.1  
Illustrated Wiring Diagram  
Central Heating  
NTC Sensor  
b
DHW  
NTC Sensor  
b
Overheat Stat  
Hall Effect  
Sensor  
b
r
b
Water Pressure  
Switch  
r
Flue Sensor  
1
4
2
g
5
br  
r
b
w
b
g
Fan  
3
bk  
g
1
2
b
g/y  
b
b
br  
4
3
2
X400  
X401  
1
5
4
3
2
1
5
4
3
2
1
9
8 7  
6
10  
9
8 7  
6
Timer  
bk  
br  
Control PCB  
bk  
b
X501  
5
6
7
8
r
9
1
2
1
2
3
4
5
1
2
3
4
X1  
X2  
X3  
b
bk  
br  
Flame  
Sensing  
Electrode  
br  
Pump  
w
b
bk  
br  
b
br  
br  
r
b
b
br  
b
w
r
Spark  
Generator  
L
N
bk  
b
b
a
DiverterValve  
br  
bk  
g
w
br  
GasValve  
b
Link  
Ignition  
Electrode  
g/y  
b
bk  
r
br  
Mains Input Cable  
g
- green  
br - brown  
bk - black  
g/y - green / yellow  
- red  
r
b
- blue  
w
- white  
50  
© Baxi Heating UK Ltd 2008  
17.0 Short Parts List  
Short Parts List  
Key  
No.  
G.C.  
No.  
Description  
Manufacturers  
Part No.  
426  
306  
326  
426  
315  
316  
422  
404  
313  
Fan  
5121447  
248733  
Motor 3way Valve  
Igniter Electrode  
Sensing Electrode  
Gas Valve  
5114702  
5114703  
5119647  
5114767  
315  
316  
311  
Hall Effect Sensor  
Burner 24  
Burner 28  
Burner 33  
5122149  
5114697  
5114698  
419  
400  
Water Pressure Switch  
Plate Heat Exchanger 24  
5114748  
248048  
419  
624  
422  
Plate Heat Exchanger 28/33 5114708  
415  
421  
420  
504  
503  
Pump  
248042  
5114725  
5114729  
248090  
NTC Sensor  
Overheat Thermostat  
Pressure Gauge  
400  
PCB 24  
PCB 28  
PCB 33  
5121862  
5120218  
5120219  
415  
421  
420  
302  
503  
504  
51  
© Baxi Heating UK Ltd 2008  
18.0 Fault Finding  
18.1  
Initial Fault Finding Checks  
NOTE: When instructed to turn the  
selector to the reset position turn the  
selector switch fully anticlockwise against  
the spring pressure to the reset position  
and hold for 5 seconds to reset the  
boiler.  
1. Check that gas, water and electrical supplies are available  
at the boiler.  
2. Electrical supply = 230V ~ 50 Hz.  
3. CH water system pressurised to 0.5 bar minimum when  
the boiler is cold.  
4. The preferred minimum gas pressure is 20 mbar.  
5. Carry out electrical system checks, i.e. Earth Continuity,  
Resistance to Earth, Short Circuit and Polarity with a suitable  
meter.  
NOTE: These checks must be repeated after any  
servicing or fault finding.  
6. Ensure all external controls are calling for heat and check  
all external and internal fuses. Before any servicing or  
replacement of parts, ensure the gas and electrical supplies  
are isolated.  
18.2  
Error Codes  
1. If a fault occurs on the boiler an error code may be shown  
by the facia display.  
2. The codes are either two or three digit, preceded by the  
letter 'E'. For example, code E133 will be displayed by 'E1'  
alternating with '33'. E50 is shown as 'E' then '50'  
Table Of Error Codes  
E20  
Central Heating NTC Fault  
Flue NTC Fault  
E28  
E20, E28 & E50 indicate faulty or incorrect components.  
E50  
Hot Water NTC Fault  
E110 shows overheat of the primary water and E130  
overheat of the flue system.  
E110  
E119  
E125  
E130  
E133  
E160  
E193  
Safety Thermostat Operated  
Water Pressure Switch Not Operated  
Circulation Fault (Primary Circuit)  
Flue NTC Operated  
E119 is displayed when the primary water pressure is less  
than 0.5 bar.  
Interruption Of Gas Supply or Flame Failure  
Fan or Fan Wiring Fault  
E133 indicates that the gas supply has been interrupted,  
ignition has failed or the flame has not been detected.  
Pre-Circulation Fault  
E125 is displayed in either of two situations:-  
i) If within 15 seconds of the burner lighting the boiler  
temperature has not changed by 1°.  
ii) If within 10 minutes of the burner lighting the boiler  
temperature twice exceeds the selected temperature by 30°.  
In these instances poor primary circulation is indicated.  
3. By turning the selector switch to the 'Reset' position for a  
minimum of 5 seconds when E110, E130 & E133 are  
displayed it is possible to relight the boiler.  
4. If this does not have any effect, or the codes are displayed  
regularly further investigation is required.  
52  
© Baxi Heating UK Ltd 2008  
18.0 Fault Finding  
Refer to Section 16.0 “Illustrated Wiring Diagram” for position of terminals and components  
Central Heating - Follow operational sequence (do  
Turn selector switch to  
The display illuminates  
NO  
Go to section ‘A’  
YES  
Error 110 flashing  
Error 130 flashing  
Error 133 flashing  
If the error 110 is still flashing.  
Go to section ‘J’  
Turn the selector switch to  
reset position for 5 seconds  
YES  
YES  
NO  
YES  
YES  
Error 20, 28 or 50 flashing  
NO  
Go to section ‘E’  
Error 119 flashing  
Go to section ‘C’  
NO  
Ensure controls are set to  
demand and verify the  
contacts are closed  
NO  
Turn Central Heating  
thermostat to Maximum.  
Pump runs  
Ensure all controls (and  
integral clock if fitted) are  
calling for heat  
NO  
YES  
Go to section ‘B’  
YES  
Ensure that primary  
circulation is OK & that  
there is no blockage  
YES  
NO  
Error 125 or 193 flashing  
NO  
3-way valve is open to Central  
Heating circuit  
Go to section ‘K’  
YES  
NO  
NO  
Error 160 flashing  
Go to section ‘D’  
Fan runs  
YES  
Error 160 flashing  
Go to section ‘L’  
Fan runs at correct speed  
YES  
Go to section ‘H’  
Turn the selector switch to  
reset  
Spark at ignition electrodes for  
up to 5 seconds and for 3  
attempts  
YES  
YES  
NO  
YES  
Error 133 flashing  
Go to section ‘F’  
YES  
NO  
Burner does not stay alights  
after 5 seconds  
Error 133 flashing  
Go to section ‘I’  
Burner lights  
Check the Central Heating  
NTC sensor  
YES  
NO  
Go to section ‘E’  
Burner output modulates to  
maintain the temperature set  
Error 130 flashing  
Go to section ‘M’  
YES  
Pump continues to run for 3  
YES  
YES  
YES  
Operation sequence  
successful  
Burner goes out  
Fan stops after 10 seconds  
minutes  
(room thermostat open)  
53  
© Baxi Heating UK Ltd 2008  
18.0 Fault Finding  
Domestic Hot Water - Follow operational sequence  
Turn selector switch to  
The display illuminates  
NO  
Go to section ‘A’  
YES  
YES  
Error 110 flashing  
Error 133 flashing  
If the error 110 is still flashing.  
Go to section ‘J’  
Turn the selector switch to  
reset position for 5 seconds  
YES  
NO  
YES  
YES  
Error 20, 28 or 50 flashing  
NO  
Go to section ‘E’  
Go to section ‘C’  
Error 119 flashing  
Go to section ‘B’  
YES  
NO  
Turn Domestic Hot Water  
thermostat to Maximum.  
Open DHW tap fully.  
DHW Hall Effect sensor  
operated (red neon on the  
sensor illuminated  
Is mains water filter and  
assembly clean?  
Is the magnetic detector free  
to move in the Hall Effect  
sensor  
NO  
NO  
YES  
DHW flow rate more than 2  
l/min  
YES  
3-way valve is open to  
Domestic Hot Water circuit  
Go to section ‘K’  
YES  
Error 125 flashing  
Go to section ‘B’  
NO  
NO  
Pump runs  
YES  
Error 160 flashing  
Go to section ‘D’  
Fan runs  
YES  
NO  
NO  
Error 160 flashing  
Go to section ‘L’  
Fan runs at correct speed  
YES  
Go to section ‘H’  
Turn the selector switch to the  
reset position for 5 seconds  
Spark at ignition electrodes for  
up to 5 seconds and for 3  
attempts  
YES  
Error 133 flashing  
Go to section ‘F’  
YES  
NO  
YES  
NO  
YES  
NO  
Burner does not stay alights  
after 5 seconds  
Error 133 flashing  
Go to section ‘I’  
Burner lights  
YES  
Clean DHW NTC sensor  
and DHW heat exchanger  
Reduce DHW flow rate  
Burner modulates  
Burner output modulates to  
maintain the temperature set  
NO  
Error 130 flashing  
Go to section ‘M’  
YES  
Close DHW tap  
YES  
YES  
DHW flow sensor senses no  
flow. Burner goes out  
YES  
YES  
Operation sequence  
successful  
Fan stops after 10 seconds  
Pump runs for 30 seconds  
54  
© Baxi Heating UK Ltd 2008  
18.0 Fault Finding  
Fault Finding Solutions Sections  
Is there 230V at:  
A
NO  
NO  
NO  
1.  
2.  
3.  
Main terminals L and N  
Main terminal fuse  
Check electrical supply  
Replace fuse  
NO  
Display  
illuminated  
Replace PCB  
Check wiring  
PCB - X1 connector  
terminals 1,2  
Is there 230V at:  
YES  
B
NO  
NO  
1.  
2.  
Pump  
If pump jammed, release  
Replace pump  
Replace PCB  
PCB - X3 connector terminals 3 & 4  
YES  
Change pump supply cable  
YES  
1.  
CH system pressure less than 0.5 bar  
NO  
Re-pressurise system  
C
Check connection water pressure  
switch terminal  
YES  
Replace water  
pressure switch  
COM - NO and PCB connector  
X400 terminals 3,4  
2.  
1.  
NO  
Check the tap of the automatic air  
vent is opened  
Open the automatic air vent  
D
Fan connections correct at fan. PCB -  
X2 connector, is 230V AC across  
terminals 5 & 7  
YES  
YES  
Fan jammed or faulty winding  
Replace PCB  
Replace fan  
NO  
55  
© Baxi Heating UK Ltd 2008  
18.0 Fault Finding  
E
F
E20 or E50 - Temperature sensors faulty.  
Cold resistance approximately  
10kΩ @ 25° C (DHW and CH sensors)  
20kΩ @ 25° C (Flue sensor)  
NO  
Replace sensor or PCB (E28)  
(resistance reduces with increase in temp.)  
E28 - Incorrect PCB fitted  
1.  
Check and correct the connection of the  
tube between the venturi and gas valve  
NO  
2.  
Gas at burner  
Ensure gas is on and purged  
YES  
PCB - X3 connector is 230V AC across  
terminals 1 & 2  
Replace gas valve  
NO  
Replace PCB  
G
H
1.  
Ensure that the Hall Effect Sensor is in position.  
Check the connection between the PCB - X400  
connector terminals 3,6,7 and the electronic sensor  
YES  
Check the voltage between red wire and blue  
wire is more than 5V DC  
YES  
NO  
Replace PCB  
Replace Hall  
Effect Sensor  
Voltage at PCB - X2 connector is at  
least 100V DC across terminals 2 & 5  
(Note: from multimeter connect  
‘common’ to 2 & ‘volts’ to 5).  
Check wiring  
NO  
YES  
Check and correct if necessary  
Replace PCB  
YES  
1. Ignition electrode and lead  
2. Electrode connection  
3. Spark gap and position  
Replace igniter  
Burner  
Viewing Window  
7.5  
1
4
0.5  
10  
1
Electrode Position  
56  
© Baxi Heating UK Ltd 2008  
18.0 Fault Finding  
1.  
2.  
Check the gas supply pressure:  
For Natural Gas greater than  
10 - 11 mbar  
I
Check and correct if necessary  
1. The mechanical set of the gas valve  
(CO2 values - see instruction)  
2. Flame sensing electrode and lead connections  
3. Flame sensing electrode position  
YES  
NO  
Replace PCB  
Replace flame sensing electrode  
Flame current should be more than 0.5 μA  
1.  
Overheat thermostat operated or  
NO  
Allow to cool. Continuity  
across thermostat terminals  
more than 1.5 ohm  
J
YES  
Replace safety thermostat  
faulty, i.e. continuity across  
thermostat terminals  
YES  
Replace PCB  
Is there 230V at:  
K
YES  
1.  
Motor 3-way valve  
Replace motor 3-way valve  
NO  
2. PCB - X3 connector terminals  
5 & 6 central heating mode  
Replace PCB  
5 & 7 domestic hot water mode  
YES  
Change pump supply cable  
1.  
L
YES  
Fan connections correct at fan.  
PCB - X401 connector terminals 5,6,7 & 8  
Replace fan  
M
1.  
2.  
Temperature sensors faulty.  
Cold resistance approximately  
10kΩ @ 25° C (CH sensor)  
20kΩ @ 25° C (Flue sensor)  
(resistance reduces with increase in temp.)  
NO  
Replace sensor  
If pump is running the heat exchanger could be  
obstructed  
YES  
Replace heat exchanger  
57  
© Baxi Heating UK Ltd 2008  
5 1 1 6 2 8 2  
BENCHMARK No.  
GAS BOILER COMMISSIONING CHECKLIST  
C O L L E C T I V E M A R K  
BOILER SERIAL No.  
NOTIFICATION No.  
CONTROLS To comply with the Building Regulations, each section must have a tick in one or other of the boxes  
TIME & TEMPERATURE CONTROL TO HEATING ROOM T/STAT & PROGRAMMER/TIMER  
TIME & TEMPERATURE CONTROL TO HOT WATER CYLINDER T/STAT & PROGRAMMER/TIMER  
PROGRAMMABLE ROOMSTAT  
COMBI BOILER  
HEATING ZONE VALVES  
FITTED  
FITTED  
FITTED  
FITTED  
NOT REQUIRED  
HOT WATER ZONE VALVES  
NOT REQUIRED  
THERMOSTATIC RADIATOR VALVES  
AUTOMATIC BYPASS TO SYSTEM  
NOT REQUIRED  
FOR ALL BOILERS CONFIRM THE FOLLOWING  
THE SYSTEM HAS BEEN FLUSHED IN ACCORDANCE WITH THE BOILER MANUFACTURER’S INSTRUCTIONS?  
THE SYSTEM CLEANER USED  
THE INHIBITOR USED  
FOR THE CENTRAL HEATING MODE, MEASURE & RECORD  
GAS RATE  
m3/hr  
N/A  
ft3/hr  
mbar  
°C  
BURNER OPERATING PRESSURE (IF APPLICABLE)  
CENTRAL HEATING FLOW TEMPERATURE  
CENTRAL HEATING RETURN TEMPERATURE  
°C  
FOR COMBINATION BOILERS ONLY  
HAS A WATER SCALE REDUCER BEEN FITTED?  
YES  
NO  
WHAT TYPE OF SCALE REDUCER HAS BEEN FITTED?  
FOR THE DOMESTIC HOT WATER MODE, MEASURE & RECORD  
m3/hr  
N/A  
GAS RATE  
ft3/hr  
mbar  
°C  
MAXIMUM BURNER OPERATING PRESSURE (IF APPLICABLE)  
COLD WATER INLET TEMPERATURE  
HOT WATER OUTLET TEMPERATURE  
WATER FLOW RATE  
°C  
lts/min  
FOR CONDENSING BOILERS ONLY CONFIRM THE FOLLOWING  
THE CONDENSATE DRAIN HAS BEEN INSTALLED IN ACCORDANCE WITH  
THE MANUFACTURER’S INSTRUCTIONS?  
YES  
FOR ALL INSTALLATIONS CONFIRM THE FOLLOWING  
THE HEATING AND HOT WATER SYSTEM COMPLIES  
WITH CURRENT BUILDING REGULATIONS  
THE APPLIANCE AND ASSOCIATED EQUIPMENT HAS BEEN INSTALLED AND COMMISSIONED  
IN ACCORDANCE WITH THE MANUFACTURER’S INSTRUCTIONS  
IF REQUIRED BY THE MANUFACTURER, HAVE YOU RECORDED A CO/CO2 RATIO READING? N/A  
YES  
CO/CO2 RATIO  
THE OPERATION OF THE APPLIANCE AND SYSTEM  
CONTROLS HAVE BEEN DEMONSTRATED TO THE CUSTOMER  
THE MANUFACTURER’S LITERATURE HAS BEEN LEFT WITH THE CUSTOMER  
COMMISSIONING ENG’S NAME PRINT  
CORGI ID No.  
DATE  
SIGN  
58  
SERVICE INTERVAL RECORD  
It is recommended that your heating system is serviced regularly  
and that you complete the appropriate Service Interval Record Below.  
Service Provider. Before completing the appropriate Service Interval Record below, please ensure you have carried out the service  
as described in the boiler manufacturer’s instructions. Always use the manufacturer’s specified spare part when replacing all controls  
SERVICE 1 DATE  
ENGINEER NAME  
COMPANY NAME  
TEL No.  
SERVICE 2 DATE  
ENGINEER NAME  
COMPANY NAME  
TEL No.  
CORGI ID CARD SERIAL No.  
COMMENTS  
CORGI ID CARD SERIAL No.  
COMMENTS  
SIGNATURE  
SIGNATURE  
SERVICE 3 DATE  
ENGINEER NAME  
COMPANY NAME  
TEL No.  
SERVICE 4 DATE  
ENGINEER NAME  
COMPANY NAME  
TEL No.  
CORGI ID CARD SERIAL No.  
COMMENTS  
CORGI ID CARD SERIAL No.  
COMMENTS  
SIGNATURE  
SIGNATURE  
SERVICE 5 DATE  
ENGINEER NAME  
COMPANY NAME  
TEL No.  
SERVICE 6 DATE  
ENGINEER NAME  
COMPANY NAME  
TEL No.  
CORGI ID CARD SERIAL No.  
COMMENTS  
CORGI ID CARD SERIAL No.  
COMMENTS  
SIGNATURE  
SIGNATURE  
SERVICE 7 DATE  
ENGINEER NAME  
COMPANY NAME  
TEL No.  
SERVICE 8 DATE  
ENGINEER NAME  
COMPANY NAME  
TEL No.  
CORGI ID CARD SERIAL No.  
COMMENTS  
CORGI ID CARD SERIAL No.  
COMMENTS  
SIGNATURE  
SIGNATURE  
SERVICE 9 DATE  
ENGINEER NAME  
COMPANY NAME  
TEL No.  
SERVICE 10 DATE  
ENGINEER NAME  
COMPANY NAME  
TEL No.  
CORGI ID CARD SERIAL No.  
COMMENTS  
CORGI ID CARD SERIAL No.  
COMMENTS  
SIGNATURE  
SIGNATURE  
59  
All descriptions and illustrations provided in this leaflet have been carefully  
prepared but we reserve the right to make changes and improvements in  
our products which may affect the accuracy of the information contained in  
this leaflet. All goods are sold subject to our standard Conditions of Sale  
which are available on request.  
POTTERTON  
A Trading Division of Baxi Heating UK Ltd (3879156)  
A Division of Baxi Group  
Brooks House, Coventry Road, Warwick. CV34 4LL  
After Sales Service 08706 017 017 Technical Enquiries 08706 049 049  
Website www.potterton.co.uk  
e&oe  
IT Comp No 925.659.2  
o
UK Comp N 5116282 - Iss 7 - 4/08  

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