Potterton Performa System 12 HE Installation and maintenance instructions

Installation & Service Instructions Performa
System HE
This is a Wall Mounted Powered Flue Condensing Boiler Gas Fired Central Heating Unit.
The boiler meets the requirements of Statutory Instrument “ The Boiler (Efficiency) Regulations 1993 No3083” and is
deemed to meet the requirements of Directive 92/42/EEC on the energy efficiency requirements for new hot water
boilers fired with liquid or gaseous fuels:-
Type test for purpose of Regulation 5 certified by:
Notified Body 0051.
Product/Production certified by:
Notified Body 0051.
For use in GB/IE only.
These instructions include the Benchmark Commissioning Checklist and should be left with the User for safe keeping.

Publication No. 5111817
2
Natural Gas
Potterton Performa System 12 HE
G.C.No41 591 24
Potterton Performa System 18 HE
G.C.No41 591 25
Potterton Performa System 24 HE
G.C.No41 591 26
Potterton Performa System 28 HE
G.C.No41 591 27
This product has an energy rating (B) on a scale of A to G.
For more information see www.boilers.org.uk. This is a certification mark.
Building Regulations and the Benchmark
Commissioning Checklist
Building Regulations (England & Wales) require
notification of the installation of a heating appliance to
the relevant Local Authority Building Control
Department. From 1 April 2005 this can be achieved via
a Competent Persons Self Certification Scheme as an
option to notifying the Local Authority directly. Similar
arrangements will follow for Scotland and will apply in
Northern Ireland from 1 January 2006.
CORGI operate a Self Certification Scheme for gas
heating appliances.
These arrangements represent a change from the
situation whereby compliance with Building Regulations
was accepted as being demonstrated by completion of
the Benchmark Logbook (which was then left on site
with the customer).
With the introduction of Self Certification Schemes, the
Benchmark Logbook is being withdrawn. However, a
similar document in the form of a commissioning
checklist and service interval record is incorporated at
the back of these instructions.
Potterton is a member of the Benchmark initiative and
fully supports the aims of the programme. Its aim is to
improve the standards of installation and commissioning
of central heating systems in the UK and to encourage
the regular servicing of all central heating systems to
ensure safety and efficiency.
Building Regulations require that installations should
comply with manufacturer's instructions. It is therefore
important that the commissioning checklist is completed
by the installer. The relevant section of Building
Regulations only relates to dwellings. Therefore the
checklist only applies if the appliance is being installed
in a dwelling or some related structure.
The flowchart opposite gives guidance for installers on
the process necessary to ensure compliance with
Building Regulations.

3
INSTALLER NOTIFICATION GUIDELINES
Publication No. 5111817
Choose Building
Regulations Notification
Route
Contact your relevant Local
Authority Building Control
(LABC) who will arrange
an inspection or contact
a government approved
inspector
LABC will record the data
and will issue a
certificate of compliance
CORGI will record the data and
will send a certificate of
compliance to the property
You must ensure that the
notification number issued by
CORGI is writen onto the
Benchmark Checklist
Scheme Members only
Call CORGI on: 0870 88 88 777
or log onto:
www.corgi-notify.com
within 10 days
If you notify via CORGI Scheme,
CORGI will then notify the
relevant Local Authority
Building Control Scheme
on member's behalf
Complete the
Benchmark Checklist
Install and Commission this
appliance to manufacturer's
instructions
Competent Person's
Self Certification Scheme Building Control

LEGISLATION
4Publication No. 5111817
Codes of Practice, most recent version should
be used
IMPORTANT - Installation, Commissioning, Service & Repair
This appliance must be installed in accordance with the manufacturer’s
instructions and the regulations in force. Read the instructions fully before
installing or using the appliance.
In GB, this must be carried out by a competent person as stated in the Gas
Safety (Installation & Use) Regulations.
Definition of competence: A person who works for a CORGI registered
company and holding current certificates in the relevant ACS modules, is
deemed competent.
In IE, this must be carried out by a competent person as stated in I.S. 813
“Domestic Gas Installations”.
Lifting - This product should be lifted and handled by two people. Stooping
should be avoided and protective equipment worn where necessary. Carrying
& lifting equipment should be used as required, e.g. when installing in in a loft
space.
The addition of anything that may interfere with the normal operation of the
appliance without express written permission from the manufacturer or his
agent could invalidate the appliance warranty. In GB this could also infringe
the Gas Safety (Installation and Use) Regulations.
Warning - Check the information on the data plate is compatible with local
supply conditions.
All CORGI registered installers carry a CORGI identification card and have a
registration number. You can check your installer is registered by telephoning
0870 4012300 or writing to:-
1 Elmwood,
Chineham Business Park,
Crockford Lane,
Basingstoke. RG24 8WG
or check online at www.corgi-gas-safety.com
Potterton declare that no substances harmful to
health are contained in the appliance or used
during appliance manufacture.
The appliance is suitable only for installation in GB
and IE and should be installed in accordance with
the rules in force, and only used in a suitably
ventilated location.
In GB, the installation must be carried out by a CORGI
Registered Installer. It must be carried out in accordance
with the relevant requirements of the:
•Gas Safety (Installation & Use) Regulations.
•The appropriate Building Regulations either The
Building Regulations, The Building Regulations
(Scotland), Building Regulations (Northern Ireland).
•The Water Fittings Regulations or Water Byelaws in
Scotland.
•The Current I.E.E. Wiring Regulations.
Where no specific instructions are given, reference
should be made to the relevant British Standard Code of
Practice.
In IE, the installation must be carried out by a competent
Person and installed in accordance with the current
edition of I.S. 813 ‘Domestic Gas Installations’, the
current Building Regulations and reference should be
made to the current ETCI rules for electrical installation.
All systems must be thoroughly flushed and
treated with inhibitor (see section 6.1).
In GB the following Codes of Practice apply:
Standard Scope
BS 6891 Gas Installation.
BS 5546 Installation of hot water supplies for
domestic purposes.
BS 5449 Forced circulation hot water systems.
BS 6798 Installation of gas fired hot water boilers.
BS 5440 Part 1 Flues.
BS 5440 Part 2 Ventilation.
BS 7074 Expansion vessels and ancillary equipment
for sealed water systems.
BS 7593 Treatment of water in domestic hot water
central heating systems.
In IE the following Codes of Practice apply:
Standard Scope
I.S. 813 Domestic Gas Installations.
The following BS standards give valuable additional information;
BS 5546 Installation of hot water supplies for
domestic purposes.
BS 5449 Forced circulation hot water systems.
BS 7074 Expansion vessels and ancillary equipment
for sealed water systems.
BS 7593 Treatment of water in domestic hot water
central heating systems.

5
CONTENTS
Publication No. 5111817
1.0 Introduction 6
2.0 General Layout 7
3.0 Appliance Operation 8
4.0 Technical Data 9
5.0 Dimensions and Fixings 13
6.0 System Details 14
7.0 Site Requirements 16
8.0 Installation 22
9.0 Commissioning 27
10.0 Completion 29
11.0 Servicing 30
12.0 Changing Components 32
13.0 Electrical 41
14.0 Short Parts List 42
15.0 Fault Finding 43
Benchmark Checklist 46
Section Page

1.0 INTRODUCTION
6Publication No. 5111817
1.1 Description
1. The Potterton Performa System HE range are fully
automatic gas fired wall mounted system boilers.
They are room sealed and fan assisted.
2. The boilers are set to give a maximum output of
12.5kW, 18.9kW, 25.2kW or 29.3kW when in
condensing mode.
3. They are designed for use on Natural Gas (G20)
and can be converted to use Propane.
4. The boiler incorporates a circulating pump and
expansion vessel. It is suitable for use only on fully
pumped sealed systems.
5. The boiler data badge gives details of the model,
serial number and Gas Council number and is
situated on the control box. It is visible when the case
front panel is removed (Fig. 1).
6. The boiler is intended to be installed in residential /
commercial / light industrial E.M.C. environments on a
governed meter supply only.
7. The boiler must be installed with one of the
purpose designed flues such as the standard
horizontal flue kit, part no. 5111073
8. All systems must be thoroughly flushed and
treated with inhibitor (see section 6.1).
1.2 Optional Extras
Various flue extensions, bends, vertical flue
kits,control accessories etc. are available as optional
extras. These are detailed in a separate publication.
NOTE: There are several detail differences
between each model. Generally these do not
affect the installation or maintenance of the boiler,
unless otherwise stated.
Data Badge
Fig. 1
Control Box
Case Front Panel

7
2.0 GENERAL LAYOUT
Publication No. 5111817
2.1 Layout
1. Air Pressure Switch
2. Expansion Vessel
3. Burner Manifold
4. Automatic Air Vent
5. Circulation Pump
6. Drain Off Point
7. Pressure Relief Valve
8. System Pressure Gauge
9. PCB
10. Control Box
11. Condensate Trap
12. Flame Sensing Electrode
13. Spark Electrode
14. Burner
15. Primary Heat Exchanger
16. Fan Assembly
17. Secondary Heat Exchanger
18. On/Off/Reset Selector Switch
19. Temperature Control
20. Flame Failure or Blocked Condensate Drain
21. Safety Thermostat Activated (Boiler or Flue)
22. Fault on Fan or Flue
23. Fault on Pump or Low System Pressure
24. Fault on Temperature Sensor
25. Fault on Temperature Sensor
26. Power On
27. Boiler On
28. Burner On
When neons 20 to 25 are constantly illuminated, they
indicate the temperature of the central heating water.
16
15
14
11
12
13
10 9
8
18 19 8
6
5
3
4
7
2
1
2
1
0
4
3
bar
30°40°50°60°70°80°
Reset
30°40°50°60°70°80°
20 21 22 23 25
26 27 28
24
17

3.0 APPLIANCE OPERATION
8Publication No. 5111817
3.1 Operating Mode (Fig. 2)
1. With a demand for heating, the pump circulates
water through the primary circuit. At a pre-determined
flow rate the hydraulic differential pressure switch
operates, initiating the ignition sequence.
2. The main burner ignites at low rate, then the gas
valve controls the gas rate to maintain the heating
temperature measured by the temperature sensor.
3. When the flow temperature exceeds the setting
temperature, a 3 minute delay occurs before the
burner relights automatically (anti-cycling). The pump
continues to run during this period.
4. When the demand is satisfied the burner is
extinguished and the pump continues to run for a
period of 3 minutes (Pump Overrun).
IMPORTANT: When the selector switch is in the
‘0’(Off) position the electrical supply to the boiler is
isolated. The boiler will not operate.
3.2 Frost Protection Mode
1. The frost protection mode is integral to the
appliance and functions when the selector switch (see
Section 2.1) is in the ON 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. Further protection
can be incorporated by using a system frost
thermostat.
3.3 Pump Protection
1. With the selector switch (see Section 2.1) in the
ON position ( ) the pump will automatically
operate for 1 minute in every 24 hours to prevent
sticking.
1
2
4
5 6
7
8
19
18
9
10 1211
14
13
15
16
17
3
Key
1 Heat Exchanger
2 Burner
3 Ignition Electrode
4 Flame Sensing Electrode
5 Gas Valve
6 Pump
7 Automatic Air Vent
8 Pressure Relief Valve
9 Boiler Drain Point
10 Gas Inlet
11 Boiler Flow
12 Boiler Return
13 Pressure Gauge
14 Automatic By-Pass
15 Hydraulic Differential Pressure Sensor
16 Safety Thermostat
17 Temperature Sensor
18 Expansion Vessel
19 Temperature Sensor
20 Secondary Heat Exchanger
Boiler Primary Circuit
Fig. 2
20

9
4.0 TECHNICAL DATA
Publication No. 5111817
4.1 System 12 HE
Flue Terminal Diameter 100mm
Dimensions Projection 125mm
Outercase Dimensions
Casing Height - 780mm
Overall Height Inc Flue
Elbow - 965mm
Casing Width - 450mm
Casing Depth - 345mm
Clearances
Above Casing 200 mm Min
Below Casing 200 mm Min
Front 450 mm Min (For Servicing)
Front 5 mm Min (In Operation)
L.H. Side 5mm Min
R.H. Side 5mm Min (In Operation)
20mm Min (See Note*)
*NOTE: The boiler can be operated with a
clearance of 5mm at the right. This is also
sufficient for routine maintenance.
However a clearance of 20mm is required
if it is necessary to remove the secondary
heat exchanger. This should be
considered when siting the appliance and
in the event of any subsequent alterations
in the area of installation
Weights kg
Packaged Boiler Carton 48.5
Installation Lift Weight 38
Central Heating Primary Circuit
Pressures
bar
Safety Discharge 3
Max Operating 2.5
Min Operating 0.5
Recommend Operating 1-2
Pump
Available Head See graph below
Expansion Vessel - (For Central Heating
only. Integral with appliance)
bar
Min Pre-charge Pressure 0.5
litre
Max Capacity of
CH System 125
Primary Water Content
of Boiler (unpressurised) 1.2
Connections copper tails
Gas Supply - 22mm
Central Heating Flow - 22mm
Central Heating Return - 22mm
Pressure Relief Discharge - 15mm
Temperatures
Flow Temp (adjustable)
35°C to 85°C max (± 5°C)
Heat Input
Max Min
kW 12.6 7
Electrical Supply 230V~ 50Hz
(Appliance must be connected to an
earthed supply)
Power Consumption 140W
External Fuse Rating 3A
Internal Fuse Rating
Fuse 2A Fast Blow to BS 4265
Appliance Category CAT II 2H 3P
Max Gas Rate (Natural Gas - G20)
(After 10 Mins)
m3/h 1.33
Inlet Pressure (Natural Gas - G20)
mbar 20
Burner Injector (Natural Gas - G20)
10 x 1.18mm Diameter
Burner Pressure (Natural Gas - G20)
Max Rate Min Rate
mbar 5.7 ± 0.5 1.9 ± 0.5
Appliance Type C12 C32 NOxClass 3
Electrical Protection
IPX5D
Heat Output (Non-Condensing)
Max Min
kW 12 6.5
Heat Output (Condensing)
Max Min
kW 12.5 6.7
Condensate Drain 1”BSP
0
200 400 600 800 1000 1200
0.5
1
1.5
2
2.5
3
3.5
4
Metre (wg)
Flow Rate (l/h)
Pump - Available Head
0
5
4.5
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 have been certified by 0051.
SEDBUK Declaration For Performa System 12 HE
The seasonal efficiency (SEDBUK) is 86.8% (86.6% LPG)
Band B
LPG Propane - G31
Burner Injector 0.69mm diameter
Burner Pressure
Propane mbar
Inlet Pressure
mbar
Max Rate
23.4 ± 0.5
Min Rate
7.4 ± 0.2
37

4.0 TECHNICAL DATA
10 Publication No. 5111817
4.2 System 18 HE
Flue Terminal Diameter 100mm
Dimensions Projection 125mm
Outercase Dimensions
Casing Height - 780mm
Overall Height Inc Flue
Elbow - 965mm
Casing Width - 450mm
Casing Depth - 345mm
Clearances
Above Casing 200 mm Min
Below Casing 200 mm Min
Front 450 mm Min (For Servicing)
Front 5 mm Min (In Operation)
L.H. Side 5mm Min
R.H. Side 5mm Min (In Operation)
20mm Min (See Note*)
*NOTE: The boiler can be operated with a
clearance of 5mm at the right. This is also
sufficient for routine maintenance.
However a clearance of 20mm is required
if it is necessary to remove the secondary
heat exchanger. This should be
considered when siting the appliance and
in the event of any subsequent alterations
in the area of installation
Weights kg
Packaged Boiler Carton 49
Installation Lift Weight 38.5
Central Heating Primary Circuit
Pressures
bar
Safety Discharge 3
Max Operating 2.5
Min Operating 0.5
Recommend Operating 1-2
Pump
Available Head See graph below
Expansion Vessel - (For Central Heating
only. Integral with appliance)
bar
Min Pre-charge Pressure 0.5
litre
Max Capacity of
CH System 125
Primary Water Content
of Boiler (unpressurised) 1.2
Connections copper tails
Gas Supply - 22mm
Central Heating Flow - 22mm
Central Heating Return - 22mm
Pressure Relief Discharge - 15mm
Temperatures
Flow Temp (adjustable)
35°C to 85°C max (± 5°C)
Heat Input
Max Min
kW 18.7 10.6
Electrical Supply 230V~ 50Hz
(Appliance must be connected to an
earthed supply)
Power Consumption 140W
External Fuse Rating 3A
Internal Fuse Rating
Fuse 2A Fast Blow to BS 4265
Appliance Category CAT II 2H 3P
Max Gas Rate (Natural Gas - G20)
(After 10 Mins)
m3/h 1.98
Inlet Pressure (Natural Gas - G20)
mbar 20
Burner Injector (Natural Gas - G20)
12 x 1.18mm Diameter
Burner Pressure (Natural Gas - G20)
Max Rate Min Rate
mbar 8.6 ± 0.5 3 ± 0.5
Appliance Type C12 C32 NOxClass 3
Electrical Protection
IPX5D
Heat Output (Non-Condensing)
Max Min
kW 18 9.9
Heat Output (Condensing)
Max Min
kW 18.9 10.2
Condensate Drain 1”BSP
0
200 400 600 800 1000 1200
0.5
1
1.5
2
2.5
3
3.5
4
Metre (wg)
Flow Rate (l/h)
Pump - Available Head
0
5
4.5
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 have been certified by 0051.
SEDBUK Declaration For Performa System 18 HE
The seasonal efficiency (SEDBUK) is 87.4% (87.3% LPG)
Band B
LPG Propane - G31
Burner Injector 0.77mm diameter
Burner Pressure
Propane mbar
Inlet Pressure
mbar
Max Rate
20 ± 0.5
Min Rate
6.6 ± 0.2
37

11
4.0 TECHNICAL DATA
Publication No. 5111817
4.3 System 24 HE
Flue Terminal Diameter 100mm
Dimensions Projection 125mm
Outercase Dimensions
Casing Height - 780mm
Overall Height Inc Flue
Elbow - 965mm
Casing Width - 450mm
Casing Depth - 345mm
Clearances
Above Casing 200 mm Min
Below Casing 200 mm Min
Front 450 mm Min (For Servicing)
Front 5 mm Min (In Operation)
L.H. Side 5mm Min
R.H. Side 5mm Min (In Operation)
20mm Min (See Note*)
*NOTE: The boiler can be operated with a
clearance of 5mm at the right. This is also
sufficient for routine maintenance.
However a clearance of 20mm is required
if it is necessary to remove the secondary
heat exchanger. This should be
considered when siting the appliance and
in the event of any subsequent alterations
in the area of installation
Weights kg
Packaged Boiler Carton 51
Installation Lift Weight 40.5
Central Heating Primary Circuit
Pressures
bar
Safety Discharge 3
Max Operating 2.5
Min Operating 0.5
Recommend Operating 1-2
Pump
Available Head See graph below
Expansion Vessel - (For Central Heating
only. Integral with appliance)
bar
Min Pre-charge Pressure 0.5
litre
Max Capacity of
CH System 125
Primary Water Content
of Boiler (unpressurised) 1.2
Connections copper tails
Gas Supply - 22mm
Central Heating Flow - 22mm
Central Heating Return - 22mm
Pressure Relief Discharge - 15mm
Temperatures
Flow Temp (adjustable)
35°C to 85°C max (± 5°C)
Heat Input
Max Min
kW 24.8 10.6
Electrical Supply 230V~ 50Hz
(Appliance must be connected to an
earthed supply)
Power Consumption 170W
External Fuse Rating 3A
Internal Fuse Rating
Fuse 2A Fast Blow to BS 4265
Appliance Category CAT II 2H 3P
Max Gas Rate (Natural Gas - G20)
(After 10 Mins)
m3/h 2.62
Inlet Pressure (Natural Gas - G20)
mbar 20
Burner Injector (Natural Gas - G20)
15 x 1.18mm Diameter
Burner Pressure (Natural Gas - G20)
Max Rate Min Rate
mbar 10.2 ± 0.5 2 ± 0.5
Appliance Type C12 C32 NOxClass 3
Electrical Protection
IPX5D
Heat Output (Non-Condensing)
Max Min
kW 24 9.8
Heat Output (Condensing)
Max Min
kW 25.2 10.1
Condensate Drain 1”BSP
0
200 400 600 800 1000 1200
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
Metre wg
l/h
Pump - Available Head
0
This value is used in the UK Government’s Standard Assessment
Procedure (SAP) for energy rating of dwellings. The test data from
which it has been calculated have been certified by 0051.
SEDBUK Declaration For Performa System 24 HE
The seasonal efficiency (SEDBUK) is 87.4% (87.2% LPG)
Band B
LPG Propane - G31
Burner Injector 0.77mm diameter
Burner Pressure
Propane mbar
Inlet Pressure
mbar
Max Rate
21.8 ± 0.5
Min Rate
4.4 ± 0.2
37

4.0 TECHNICAL DATA
12 Publication No. 5111817
4.4 System 28 HE
Flue Terminal Diameter 100mm
Dimensions Projection 125mm
Outercase Dimensions
Casing Height - 780mm
Overall Height Inc Flue
Elbow - 965mm
Casing Width - 450mm
Casing Depth - 345mm
Clearances
Above Casing 200 mm Min
Below Casing 200 mm Min
Front 450 mm Min (For Servicing)
Front 5 mm Min (In Operation)
L.H. Side 5mm Min
R.H. Side 5mm Min (In Operation)
20mm Min (See Note*)
*NOTE: The boiler can be operated with a
clearance of 5mm at the right. This is also
sufficient for routine maintenance.
However a clearance of 20mm is required
if it is necessary to remove the secondary
heat exchanger. This should be
considered when siting the appliance and
in the event of any subsequent alterations
in the area of installation
Weights kg
Packaged Boiler Carton 51
Installation Lift Weight 40.5
Central Heating Primary Circuit
Pressures
bar
Safety Discharge 3
Max Operating 2.5
Min Operating 0.5
Recommend Operating 1-2
Pump
Available Head See graph below
Expansion Vessel - (For Central Heating
only. Integral with appliance)
bar
Min Pre-charge Pressure 0.5
litre
Max Capacity of
CH System 125
Primary Water Content
of Boiler (unpressurised) 1.2
Connections copper tails
Gas Supply - 22mm
Central Heating Flow - 22mm
Central Heating Return - 22mm
Pressure Relief Discharge - 15mm
Temperatures
Flow Temp (adjustable)
35°C to 85°C max (± 5°C)
Heat Input
Max Min
kW 28.9 11.9
Electrical Supply 230V~ 50Hz
(Appliance must be connected to an
earthed supply)
Power Consumption 180W
External Fuse Rating 3A
Internal Fuse Rating
Fuse 2A Fast Blow to BS 4265
Appliance Category CAT II 2H 3P
Max Gas Rate (Natural Gas - G20)
(After 10 Mins)
m3/h 3.06
Inlet Pressure (Natural Gas - G20)
mbar 20
Burner Injector (Natural Gas - G20)
15 x 1.25mm Diameter
Burner Pressure (Natural Gas - G20)
Max Rate Min Rate
mbar 10.9 ± 0.5 2.1 ± 0.5
Appliance Type C12 C32 NOxClass 3
Electrical Protection
IPX5D
Heat Output (Non-Condensing)
Max Min
kW 28 11
Heat Output (Condensing)
Max Min
kW 29.3 11.3
Condensate Drain 1”BSP
0
200 400 600 800 1000 1200
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
5.5
6
Metre wg
l/h
Pump - Available Head
0
This value is used in the UK Government’s Standard Assessment
Procedure (SAP) for energy rating of dwellings. The test data from
which it has been calculated have been certified by 0051.
SEDBUK Declaration For Performa System 28 HE
The seasonal efficiency (SEDBUK) is 87.3% (87.2% LPG)
Band B
LPG Propane - G31
Burner Injector 0.77mm diameter
Burner Pressure
Propane mbar
Inlet Pressure
mbar
Max Rate
29.4 ± 0.5
Min Rate
5.2 ± 0.2
37

13
5.0 DIMENSIONS AND FIXINGS
Publication No. 5111817
Dimensions
A780mm
B345mm
C450mm
D107mm ØMin.
E185mm
F190mm
G131mm
Heating
Return
(22mm)
Heating
Flow
(22mm)
Pressure Relief
Valve
(15mm)
Gas
Inlet
(22mm)
130 mm 130 mm 65 mm
Tap Rail
360°Orientation
Tube Ø100mm
DC
B
A
E
G
F
3°
28mm
Condensate
Drain

6.0 SYSTEM DETAILS
14 Publication No. 5111817
6.1 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 upgrading existing systems that exhibit
evidence of sludging, it is advisable to clean the system
prior to treatment in order to remove any sludge and
reduce the likelihood of these deposits damaging new
components.
•When fitting new systems flux will be evident within
the system, which can lead to damage of system
components.
•All systems must be thoroughly drained and flushed
out. The recommended flushing and cleansing agents
are Betz-Dearborn Sentinel X300 or X400 and Fernox
Superfloc Universal Cleanser which should be used
following the flushing agent manufacturer’s instructions.
•System additives - corrosion inhibitors and flushing
agents/descalers should be suitable for aluminium and
comply to BS7593 requirements. The only system
additives recommended are Betz-Dearborn Sentinel
X100 and Fernox-Copal which should be used following
the inhibitor manufacturer’s instructions.
Failure to flush and add inhibitor to the system
will invalidate the appliance warranty.
•It is important to check the inhibitor concentration
after installation, system modification and at every
service in accordance with the manufacturer’s
instructions. (Test kits are available from inhibitor
stockists.)
•For information or advice regarding any of the above
contact Technical Enquiries.
6.2 Bypass
1. The boiler is fitted with an automatic integral bypass.
6.3 System Control
1. For optimum operating conditions, the heating
system into which the boiler is installed should include a
control system.
2. Such a system will comprise of a timer control and
separate room or cylinder thermostats as appropriate.
3. The boiler should be controlled so that it operates on
demand only.
4. Operation of the system under control of the boiler
thermostat & TRV’s only does not produce the best
results.

15
6.0 SYSTEM DETAILS
Publication No. 5111817
6.4 System Filling and Pressurising
1. A filling point connection on the central heating
return pipework must be provided to facilitate initial
filling and pressurising and also any subsequent
water loss replacement/refilling.
2. The filling method adopted must be in accordance
with all relevant water supply regulations and use
approved equipment.
3. Your attention is drawn to: for GB: guidance G24.2
and recommendation R24.2 of the Water
Regulations Guide.
for IE: the current edition of I.S. 813 “Domestic Gas
Installations”.
4. The sealed primary circuits may be filled or
replenished by means of a temporary connection
between the circuit and a supply pipe provided a
‘Listed’double check valve or some other no less
effective backflow prevention device is permanently
connected at the inlet to the circuit and the temporary
connection is removed after use.
6.5 Expansion Vessel
1. The appliance expansion vessel is pre-charged to
0.5 bar. The vessel is suitable for correct operation
for system capacities up to 125 litres. For greater
system capacities an additional expansion vessel
must be fitted. for GB refer to BS 7074 Pt 1. For IE,
the current edition of I.S. 813 “Domestic Gas
Installations”.
6.6 Pressure Relief Valve (Fig. 4)
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.
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.
Fig. 3
Fig. 4
Stop
Valve
Double
Check
Valve
Mains
Cold
Water
CH
Return
Temporary
Hose
Pressure Relief Valve
Discharge Pipe
Stop
Valve

7.0 SITE REQUIREMENTS
16 Publication No. 5111817
7.1 Location
1. The boiler may be fitted to any suitable wall with the
flue passing through an outside wall or roof and
discharging to atmosphere in a position permitting
satisfactory removal of combustion products and
providing an adequate air supply. The boiler should
be fitted within the building unless otherwise protected
by a suitable enclosure i.e. garage or outhouse. (The
boiler may be fitted inside a cupboard-see Section
7.3).
2. If the boiler is sited in an unheated enclosure then it
is recommended to leave the On/Off/Reset Selector
Switch in the On Position.
3. If the boiler is fitted in a room containing a bath or
shower reference must be made to the relevant
requirements.
In GB this is the current I.E.E. Wiring Regulations and
Building Regulations.
In IE reference should be made to the current edition
of I.S. 813 “Domestic Gas Installations”and the
current ETCI rules.
4. If the boiler is to be fitted into a building of timber
frame construction then reference must be made to
the current edition of Institute of Gas Engineers
Publication IGE/UP/7 (Gas Installations in Timber
Framed Housing).
7.2 Clearances (Figs. 5 & 6)
1. A flat vertical area is required for the installation of
the boiler.
2. These dimensions include the necessary
clearances around the boiler for case removal,
spanner access and air movement. Additional
clearances may be required for the passage of pipes
around local obstructions such as joists running
parallel to the front face of the boiler.
*NOTE: The boiler can be operated with a
clearance of 5mm at the right. This is also
sufficient for routine maintenance. However a
clearance of 20mm is required if it is necessary to
remove the secondary heat exchanger. This
should be considered when siting the appliance
and in the event of any subsequent alterations in
the area of installation.
200mm Min
780mm
450mm
200mm Min
20mm/5mm Min
see *NOTE:
5mm Min
5mm Min
450mm Min
For Servicing
Purposes
Fig. 5
Fig. 6
In Operation

17
7.0 SITE REQUIREMENT
Publication No. 5111817
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”.
2. The connection to the appliance is a 22mm
copper tail located at the rear of the gas service
cock (Fig. 7).
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).
7.5 Electrical Supply
1. External wiring must be correctly earthed,
polarised and in accordance with relevant
regulations/rules. In GB this is the current I.E.E.
Wiring Regulations. In IE reference should be made
to the current edition of ETCI rules.
2. The mains supply must be 230V ~ 50Hzand
fused at 3A maximum.
NOTE: The method of connection to the
electricity supply must facilitate complete
electrical isolation of the appliance.
Connection may be via a fused double-pole
isolator with a contact separation of at least 3mm
in all poles and servicing the boiler and system
controls only.
3. When the system includes an indirect domestic
hot water cylinder it is recommended that a cylinder
thermostat is used in conjunction with a
3 port 2 position valve or 2 port zone valve.
Fig. 7
Gas Service Cock

7.0 SITE REQUIREMENTS
18 Publication No. 5111817
7.6 Condensate Drain
FAILURE TO INSTALL THE CONDENSATE
DISCHARGE PIPEWORK CORRECTLY WILL AFFECT
THE RELIABLE OPERATION OF THE BOILER
The condensate discharge pipe MUST NOT RISE at
any point along its length. There MUST be a fall of AT
LEAST 2.5° (50mm per metre) along the entire run.
1. The condensate outlet terminates in a 1”BSP nut and
seal for the connection of 21.5mm (3/4in) plastic overflow
pipe which should generally discharge internally into the
household drainage system. If this is not possible,
discharge into an outside drain is acceptable.
2. Ensure the discharge of condensate complies with
any national or local regulations in force.
BS 6798:2000 & Part H1 of the Building Regulations
give further guidance.
3. The discharge pipe should be run in a proprietary
drain pipe material e.g. PVC, PVC-U, ABS, PVC-C or
PP.
4. Metal pipework is NOT suitable for use in condensate
discharge systems.
5. The pipe should be a minimum of 21.5mm diameter
and must be supported using suitably spaced clips to
prevent sagging.
6. Any pipe fitted externally must not exceed 3 metres.
7. Any condensate discharge pipework external to the
building (or in an unheated part of it e.g. garage) must
be insulated to protect against frost. It is also
recommended that the pipe diameter is increased to
32mm.
8. If the boiler is fitted in an unheated location the entire
condensate discharge pipe should be treated as an
external run.
9. In all cases discharge pipe must be installed to aid
disposal of the condensate. To reduce the risk of
condensate being trapped, as few bends and fittings as
possible should be used.
10. When discharging condensate into a soil stack or
waste pipe the effects of existing plumbing must be
considered. If soil pipes or waste pipes are subjected to
internal pressure fluctuations when WC's are flushed or
sinks emptied then back-pressure may force water out of
the boiler trap and cause appliance lockout.
Examples are shown of the following methods of
termination:-
i) to an internal soil & vent pipe
ii) via an internal discharge branch (e.g. sink waste)
iii) to a drain or gully
iv) to a purpose made soakaway
Boiler
2.5°Minimum fall
Termination to an internal soil
and vent pipe
450mm min
Boiler
2.5°Minimum fall
External termination via internal
discharge branch
e.g sink waste - downstream
Sink
Pipe must terminate
above water level but
below surrounding
surface
Boiler Pipe must terminate
above water level but
below surrounding
surface
2.5°Minimum fall
Termination to a drain or gully
Boiler
500mm min
2.5°Minimum fall
Termination to a purpose made
soak-away
Holes in the soak-away
must face away from the
building
50mm per metre of pipe run
50mm per metre of pipe run
50mm per metre of pipe run
50mm per metre of pipe run

19
7.0 SITE REQUIREMENTS
Publication No. 5111817
7.7 Flue
NOTE: Due to the nature of the boiler a plume of
water vapour will be discharged from the flue. This
should be taken into account when siting the flue
terminal.
1. the following guidelines indicate the general
requirements for siting balanced flue terminals. For
GB recommendations are given in BS 5440 Pt 1. For
IE recommendations are given in the current edition
of I.S. 813 “Domestic Gas Installations”.
2. If the terminal discharges onto a pathway or
passageway, check that combustion products will not
cause a nuisance and that the terminal will not
obstruct the passageway.
3. 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.
Terminal Position with Minimum Distance (Fig. 9) (mm)
A* Directly below an openable window, air vent or any other
ventilation opening. 300
B Below gutter, drain/soil pipe. 25
C Below eaves. 25
D Below a balcony/car port roof. 25
E From vertical drain pipes and soil pipes. 25
F From internal or external corners. 25
G Above adjacent ground or balcony level. 300
H From a surface facing a terminal. 600
I Facing a terminals. 1200
J From opening (door/window) in carport into dwelling. 1200
K Vertically from a terminal on the same wall. 1500
L Horizontally from a terminal on the same wall. 300
M* Above an opening, air brick, opening window etc. 300
N* Horizontally to an opening, air brick, opening window etc. 300
L
G
G
E
J
D
K
G
AAD
F
H,I
B,C
F
Likely flue positions requiring
a flue terminal guard
M
N
Fig. 9
300 min
Terminal
Assembly
Top View Rear Flue
Property Boundary Line
Fig. 8
* In addition, the terminal should be no nearer than 150mm 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.

7.0 SITE REQUIREMENTS
20 Publication No. 5111817
7.8 Flue Dimensions
The standard horizontal flue kit allows for flue lengths
between 100mm and 685 from elbow to terminal
(Fig. 10).
The maximum permissible equivalent flue length
is: System 12 &18 HE 5 metres
System 24 HE 4 metres
System 28 HE 3 metres
7.9 Flue Trim
1. The rubber flue trim supplied may be fitted to either
the outside wall or on the inner wall of installation.
7.10 Terminal Guard (Fig. 11)
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.
Fig. 10
Fig. 11
100mm 685mm