Installation & Servicing Instructions
Baxi Platinum Combi HE Range
Gas Fired Wall Mounted Condensing
Combination Boiler
Please leave these instructions with the user
Natural Gas
Baxi Platinum Combi 24 HE
G.C.No 47 075 20
Baxi Platinum Combi 28 HE
G.C.No 47 075 21
Baxi Platinum Combi 33 HE
G.C.No 47 075 22
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Benchmark Logbook is being withdrawn.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.
Baxi 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 boiler meets the requirements of Statutory Instrument “ The
Boiler (Efficiency) Regulations 1993 No 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:-
The flowchart opposite gives guidance for installers on the
process necessary to ensure compliance with Building
Regulations.
Type test for purpose of Regulation 5 certified by:
Notified Body 0085.
Product/Production certified by:
Notified Body 0085.
For GB/IE only.
Baxi is a BS-EN ISO 9001
Accredited Company
2
Installer Notification Guidelines
Install and Commission this
appliance to manufacturer's
instructions
Complete the
Benchmark Checklist
Choose Building
Regulations Notification
Route
Competent Person's
Self Certification Scheme
If you notify via CORGI Scheme,
CORGI will then notify the
relevant Local Authority
Building Control Scheme
on member's behalf
Building Control
Contact your relevant Local
Authority Building Control
(LABC) who will arrange
an inspection or contact
a government approved
inspector
Scheme Members only
Call CORGI on: 0870 88 88 777
or log onto:
www.corgi-notify.com
within 10 days
You must ensure that the
notification number issued by
CORGI is writen onto the
Benchmark Checklist
CORGI will record the data and
will send a certificate of
compliance to the property
LABC will record the data
and will issue a
certificate of compliance
3
Legislation
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 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.
Baxi declare that no substances harmful to health are
contained in the appliance or used during appliance
manufacture.
The appliance is suitable only for installation in GB and IE and
should be installed in accordance with the rules in force, and
only used in a suitably ventilated location.
In GB, the installation must be carried out by a CORGI
Registered Installer. It must be carried out in accordance with
the relevant requirements of the:
• Gas Safety (Installation & Use) Regulations.
• The appropriate Building Regulations either The Building
Regulations, The Building Regulations (Scotland), Building
Regulations (Northern Ireland).
• The Water Fittings Regulations or Water Byelaws in
Scotland.
• The Current I.E.E. Wiring Regulations.
Where no specific instructions are given, reference should be
made to the relevant British Standard Code of Practice.
In IE, the installation must be carried out by a competent
Person and installed in accordance with the current edition of
I.S. 813 ‘Domestic Gas Installations’, the current Building
Regulations and reference should be made to the current ETCI
rules for electrical installation.
All systems must be thoroughly flushed and treated with
inhibitor (see section 6.2).
Codes of Practice - refer to the most recent version
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
4
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 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.
CONTENTS
Section
Page
1.0
Introduction
6
2.0
General Layout
7
3.0
Appliance Operation
8
4.0
Technical Data
9
5.0
Dimensions and Fixings
12
6.0
System Details
13
7.0
Site Requirements
16
8.0
Installation
22
9.0
Commissioning
28
10.0
Completion
31
11.0
Servicing
32
12.0
Changing Components
34
13.0
Combustion Check
43
14.0
Electrical
44
15.0
Short Parts List
45
16.0
Fault Finding
46
17.0
Notes
52
Benchmark Checklist
54
5
1.0 Introduction
1.1
Description
1. The Baxi Platinum Combi HE 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
25.9 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).
7. The boiler model name and serial number are also shown
on the information label on the iner face of the right hand
case panel. This is for user reference.
Control Box
Information
Label
Fig. 1
Data Badge
8. The boiler is intended to be installed in residential /
commercial / light industrial E.M.C. environments on a
governed meter supply only.
9. The boiler must be installed with one of the purpose
designed flues such as the standard horizontal flue kit, part no.
5111073.
10. All systems must be thoroughly flushed and treated with
inhibitor (see section 6.2).
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: All illustrations show the Platinum Combi 24 HE
unless otherwise stated.
6
2.0 General Layout
2.1
Layout
23
1
15
22
14
13
21
16
20
10
9
8
7
12
2
1.
Expansion Vessel
2.
Automatic Air Vent
3.
DHW Plate Heat Exchanger
4.
Circulation Pump
5.
Drain Off Point
6.
Pressure Relief Valve
7.
Integral Timer Position
8.
Central Heating System Pressure Gauge
9.
PCB
10.
Control Box
11.
3-Way Valve Assembly
12.
Condensate Trap
13.
Flame Sensing Electrode
14.
Spark Electrode
15.
Primary Heat Exchanger
16.
Fan Assembly
17.
On/Off/Reset Selector Switch
18.
Central Heating Temperature Control
19.
Hot Water Temperature Control
20.
Venturi
21.
Air/Gas Collector
22.
Combustion Box Cover & Burner
23.
Igniter
24.
Burner On Light
25.
Central Heating Mode Light
26.
Domestic Hot Water Mode Light
27.
Display
3
11
5
4
6
25
26
2
1
12
11
3
PM
10
GRASSLIN
4
0
11
19
8
12
18
1
24
2
27
3
17
4
9
0
5
bar
AM
8
7
7
8
3
1
9
5
10
4
2
7
7
3.0 Appliance Operation
1
3.1
Central Heating Circuit
Central Heating Mode (Fig. 2)
1. With a demand for heating, the pump circulates water
through the primary circuit.
2
3 4
7
26
20
5
6
25
24
18
2. Once main burner ignites the fan speed controls the gas
rate to maintain the heating temperature measured by the
temperature sensor.
3. When the flow temperature exceeds the setting
temperature, a 3 minute delay occurs before the burner
relights automatically (anti-cycling). The pump continues to
run during this period.
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).
22
9
11
23
21
3.2
10
17
16
19
15
14
13
12
Fig. 2
Key
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Primary Heat Exchanger
Burner
Ignition Electrode
Flame Sensing Electrode
Gas Valve
Pump
Automatic Air Vent
Plate Heat Exchanger
Flow Sensor with Filter & Regulator
Pressure Relief Valve
Boiler Drain Point
Heating Return
Cold Water Inlet On/Off Valve and Filter
Gas Inlet
15
16
17
18
19
20
21
22
23
24
25
26
Domestic Hot Water Outlet
Heating Flow
Pressure Gauge
Water Pressure Sensor
Automatic By-Pass
Fan
Diverter Valve Assembly
Diverter Valve Motor
Domestic Hot Water Flow Temperature Sensor
Safety Thermostat
Central Heating Temperature Sensor
Expansion Vessel
1. Priority is given to the domestic hot water supply. A
demand at a tap or shower will override any central heating
requirement.
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.
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.
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
Domestic Hot Water Circuit
3.3
2
3 4
7
26
20
5
6
25
24
18
22
9
11
23
10
17
16
Fig. 3
8
19
15
14
13
12
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. Further protection can be incorporated by using a
system frost thermostat.
3.4
8
21
Domestic Hot Water Mode (Fig. 3)
Pump Protection
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.
4.0 Technical Data
4.1
Appliance Type
C13
Appliance Category
C33
CAT I 2H
Power Consumption
155W
Electrical Protection
IPX0D
Central Heating Primary Circuit
Pressures
Safety Discharge
Max Operating
Min Operating
Recommended Operating Range
Heat Input CH (Net)
kW
Max
Min
24.7
7
F2L
Max
Min
27.4
7.8
Heat Output CH (Non-Condensing)
Max
Min
kW
24
6.8
Heat Output CH (Condensing)
Max
Min
kW
25.9
7.4
Heat Input DHW (Net)
Max
kW
24.7
Heat Input DHW (Gross)
Max
kW
27.4
Heat Output DHW
Max
kW
Max Gas Rate
3
m /h
3A
Internal Fuse Rating
Heat Input CH (Gross)
kW
External Fuse Rating
24
(Natural Gas - G20)
(After 10 mins)
2.61
Inlet Pressure (Natural Gas - G20)
mbar
20
Injector (Natural Gas - G20)
7.5mm
Electrical Supply
230V~ 50Hz
(Appliance must be connected to an
earthed supply)
NOx Class
5
Condensate Drain
To accept 21.5mm (3/4 in) plastic waste pipe
Flue Terminal
Dimensions
Diameter
Projection
Connections
Gas Supply
Central Heating Flow
Central Heating Return
Cold Water Mains Inlet
DHW Flow
Pressure Relief Discharge
Outercase Dimensions
Casing Height
Overall Height Inc Flue
Elbow
Casing Width
Casing Depth
Clearances
Above Casing
Below Casing
Front
Front
L.H. Side
R.H. Side
Platinum Combi 24 HE
100mm
125mm
-
copper tails
22mm
22mm
22mm
15mm
15mm
15mm
-
780mm
-
965mm
450mm
345mm
bar
Flow Rates
DHW Flow Rate
@ 30o C Rise
l/min
8
0.15
11.43
DHW Flow Rate
@ 35o C Rise
9.8
Min Working
DHW Flow Rate
2
Pump
Available Head
See graph below
Expansion Vessel
- (For Central Heating
only. Integral with appliance)
bar
Min Pre-charge Pressure
0.5
litre
200 mm Min
200 mm Min
450 mm Min (For Servicing)
5 mm Min (In Operation)
5 mm Min
5 mm Min (In Operation)
Weights
Packaged Boiler Carton
Installation Lift Weight
DHW Circuit
Pressures
Max Operating
Min Operating
bar
3
2.5
0.5
1-2
kg
56.5
45
Max Capacity of
CH System
125
Primary Water Content
of Boiler (unpressurised)
2.5
Temperatures
C.H. Flow Temp (adjustable)
25°C to 80°C max (± 5°C)
D.H.W. Flow Temp (adjustable)
35°C to 60°C max (± 5°C)
dependent upon flow rate
Pump - Available Head
5.5
5
SEDBUK Declaration For Platinum 24 HE
4.5
The seasonal efficiency (SEDBUK) is 90.1%
Band A
4
This value is used in the UK Government’s Standard Assessment Procedure
3.5
(SAP) for energy rating of dwellings. The test data from which it has been
3
Metre (wg)
calculated have been certified by 0085.
2.5
2
1.5
1
0.5
0
0
200
400
600
800
1000
1200
Flow Rate (l/h)
9
4.0 Technical Data
4.2
Appliance Type
C13
Appliance Category
C33
CAT I 2H
Power Consumption
155W
Electrical Protection
IPX0D
Central Heating Primary Circuit
Pressures
Safety Discharge
Max Operating
Min Operating
Recommended Operating Range
Heat Input CH (Net)
kW
Max
Min
24.7
9
F2L
Max
Min
27.4
10
Heat Output CH (Non-Condensing)
Max
Min
kW
24
8.7
Heat Output CH (Condensing)
Max
Min
kW
25.9
9.5
Heat Input DHW (Net)
Max
kW
28.9
Heat Input DHW (Gross)
Max
kW
32.1
Heat Output DHW
Max
kW
Max Gas Rate
3
m /h
3A
Internal Fuse Rating
Heat Input CH (Gross)
kW
External Fuse Rating
28
(Natural Gas - G20)
(After 10 mins)
3.1
Inlet Pressure (Natural Gas - G20)
mbar
20
Injector (Natural Gas - G20)
7.5mm
Electrical Supply
230V~ 50Hz
(Appliance must be connected to an
earthed supply)
NOx Class
5
Condensate Drain
To accept 21.5mm (3/4 in) plastic waste pipe
Flue Terminal
Dimensions
Diameter
Projection
Connections
Gas Supply
Central Heating Flow
Central Heating Return
Cold Water Mains Inlet
DHW Flow
Pressure Relief Discharge
Outercase Dimensions
Casing Height
Overall Height Inc Flue
Elbow
Casing Width
Casing Depth
Clearances
Above Casing
Below Casing
Front
Front
L.H. Side
R.H. Side
Platinum Combi 28 HE
100mm
125mm
-
copper tails
22mm
22mm
22mm
15mm
15mm
15mm
-
780mm
-
965mm
450mm
345mm
bar
Flow Rates
DHW Flow Rate
@ 30o C Rise
l/min
8
0.15
13.3
DHW Flow Rate
@ 35o C Rise
11.5
Min Working
DHW Flow Rate
2
Pump
Available Head
See graph below
Expansion Vessel
- (For Central Heating
only. Integral with appliance)
bar
Min Pre-charge Pressure
0.5
litre
200 mm Min
200 mm Min
450 mm Min (For Servicing)
5 mm Min (In Operation)
5 mm Min
5 mm Min (In Operation)
Weights
Packaged Boiler Carton
Installation Lift Weight
DHW Circuit
Pressures
Max Operating
Min Operating
kg
56.5
45
Max Capacity of
CH System
125
Primary Water Content
of Boiler (unpressurised)
2.5
Temperatures
C.H. Flow Temp (adjustable)
25°C to 80°C max (± 5°C)
D.H.W. Flow Temp (adjustable)
35°C to 60°C max (± 5°C)
dependent upon flow rate
Pump - Available Head
5.5
5
SEDBUK Declaration For Platinum 24 HE
4.5
The seasonal efficiency (SEDBUK) is 90.1%
Band A
4
This value is used in the UK Government’s Standard Assessment Procedure
3.5
(SAP) for energy rating of dwellings. The test data from which it has been
3
Metre (wg)
calculated have been certified by 0085.
2.5
2
1.5
1
0.5
0
0
200
400
600
Flow Rate (l/h)
10
bar
3
2.5
0.5
1-2
800
1000
1200
4.0 Technical Data
4.3
Appliance Type
C13
Appliance Category
C33
CAT I 2H
Power Consumption
160W
Electrical Protection
IPX0D
Central Heating Primary Circuit
Pressures
Safety Discharge
Max Operating
Min Operating
Recommended Operating Range
Heat Input CH (Net)
kW
Max
Min
28.9
9.7
F2L
Max
Min
32.1
10.8
Heat Output CH (Non-Condensing)
Max
Min
kW
28
9.4
Heat Output CH (Condensing)
Max
Min
kW
30.3
10.2
Heat Input DHW (Net)
Max
kW
34
Heat Input DHW (Gross)
Max
kW
37.7
Heat Output DHW
Max
kW
Max Gas Rate
3
m /h
3A
Internal Fuse Rating
Heat Input CH (Gross)
kW
External Fuse Rating
33
(Natural Gas - G20)
(After 10 mins)
3.6
Inlet Pressure (Natural Gas - G20)
mbar
20
Injector (Natural Gas - G20)
12mm
Electrical Supply
230V~ 50Hz
(Appliance must be connected to an
earthed supply)
NOx Class
5
Condensate Drain
To accept 21.5mm (3/4 in) plastic waste pipe
Flue Terminal
Dimensions
Diameter
Projection
Connections
Gas Supply
Central Heating Flow
Central Heating Return
Cold Water Mains Inlet
DHW Flow
Pressure Relief Discharge
Outercase Dimensions
Casing Height
Overall Height Inc Flue
Elbow
Casing Width
Casing Depth
Clearances
Above Casing
Below Casing
Front
Front
L.H. Side
R.H. Side
Platinum Combi 33 HE
100mm
125mm
-
copper tails
22mm
22mm
22mm
15mm
15mm
15mm
-
780mm
-
965mm
450mm
345mm
bar
Flow Rates
DHW Flow Rate
@ 30o C Rise
l/min
8
0.15
15.7
DHW Flow Rate
@ 35o C Rise
13.5
Min Working
DHW Flow Rate
2
Pump
Available Head
See graph below
Expansion Vessel
- (For Central Heating
only. Integral with appliance)
bar
Min Pre-charge Pressure
0.5
litre
200 mm Min
200 mm Min
450 mm Min (For Servicing)
5 mm Min (In Operation)
5 mm Min
5 mm Min (In Operation)
Weights
Packaged Boiler Carton
Installation Lift Weight
DHW Circuit
Pressures
Max Operating
Min Operating
bar
3
2.5
0.5
1-2
kg
57.5
46
Max Capacity of
CH System
155
Primary Water Content
of Boiler (unpressurised)
2.8
Temperatures
C.H. Flow Temp (adjustable)
25°C to 80°C max (± 5°C)
D.H.W. Flow Temp (adjustable)
35°C to 60°C max (± 5°C)
dependent upon flow rate
Pump - Available Head
5.5
5
SEDBUK Declaration For Platinum 24 HE
4.5
The seasonal efficiency (SEDBUK) is 90.1%
Band A
4
This value is used in the UK Government’s Standard Assessment Procedure
3.5
(SAP) for energy rating of dwellings. The test data from which it has been
3
Metre (wg)
calculated have been certified by 0085.
2.5
2
1.5
1
0.5
0
0
200
400
600
800
1000
1200
Flow Rate (l/h)
11
5.0 Dimensions and Fixings
Dimensions
3o
A 780mm
E
G
B 345mm
C 450mm
A
D 116mm Ø Min.
E 185mm
F 145mm
G 131mm
H 180mm
B
360° Orientation
H
D
C
Tube Ø 100mm
F
Tap Rail
32.5 mm
Condensate
Drain
65 mm
Heating
Flow
(22mm)
12
65 mm
Domestic Hot
Water Outlet
(15mm)
65 mm
Gas
Inlet
(22mm)
65 mm
Cold Water
Inlet
(15mm)
65 mm
Heating
Return
(22mm)
Pressure Relief
Valve
(15mm)
6.0 System Details
6.1
Information
1. The Baxi Platinum Combi HE 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.
b) IRN 302 Byelaw 14.
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 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 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.
6.3
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.
13
6.0 System Details
6.5
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.
Stop
Valve
Double
Check
Valve
DHW
Mains
Inlet
Fig. 4
Temporary
Hose
2. There are connection points on the mains cold water inlet
and central heating return isolating taps (Fig. 5) to which the
filling loop kit supplied can be assembled. If the boiler is to be
installed in a location (e.g. loft space) the filling point must be
accessible. The kit supplied can still be used for this, or if
necessary a more suitable propriety kit.
Stop
Valve
CH
Return
3. The filling method adopted must be in accordance with all
relevant water supply regulations and use approved
equipment.
4. Your attention is drawn to:
for GB: Guidance G24.2 and recommendation R24.2 of the
Water Regulations Guide.
for IE: the current edition of I.S. 813 “Domestic Gas
Installations”.
5. 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)
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. 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
Filling Loop
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.
Fig. 6
Pressure Relief Valve
Discharge Pipe
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.
14
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
Expansion
Vessel
Boiler
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
Stop Tap
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”.
To Hot
Taps
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
(eg. Zilmet 160ml, R1/2 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.
15
7.0 Site Requirements
450mm
5mm Min
5mm Min
7.1
200mm Min
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 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.
2
1
12
11
3
PM
AM
8
7
7
8
3
1
9
5
10
4
2
10
4
9
0
5
GRASSLIN
3
2
1
12
4
0
bar
11
200mm Min
Fig. 8
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
3°
Clearances (Figs. 8 & 9)
1. A flat vertical area is required for the installation of the
boiler.
2. These dimensions include the necessary clearances around
the boiler for case removal, spanner access and air
movement. Additional clearances may be required for the
passage of pipes around local obstructions such as joists
running parallel to the front face of the boiler.
450mm Min
For Servicing
Purposes
5mm Min
In Operation
Fig. 9
16
7.0 Site Requirement
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. 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).
7.5
Electrical Supply
1. External wiring must be correctly earthed, polarised and
in accordance with relevant regulations/rules. In GB this is
the current I.E.E. Wiring Regulations. In IE reference should
be made to the current edition of ETCI rules.
2. The mains supply is 230V ~ 50Hz fused at 3A.
Fig. 10
Gas Service Cock
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.
17
7.0 Site Requirements
Termination to an internal soil and
vent pipe
Boiler
50mm
per me
2.5° M
inimum
tre of
pipe ru
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.
n
fall
1. The condensate outlet will accept 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.
450mm min
External termination via internal discharge
branch
e.g sink waste - downstream
Boiler
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.
50mm
Sink
per me
tre of
2.5° M
inimum
pipe ru
n
Pipe must terminate
above water level but
below surrounding
surface
fall
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.
Termination to a drain or gully
Boiler
Pipe must terminate above
water level but below
surrounding surface
50mm
per me
2.5° M
tre of
inimum
pipe ru
n
fall
Boiler
500mm min
per me
2.5° M
tre of
inimum
18
pipe ru
fall
n
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.
Termination to a purpose made soakaway
50mm
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.
Holes in the soak-away must
face away from the building
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
7.0 Site Requirements
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.
L
K
B,C
N
G
G
D
M
J
E
A
A
F
D
H,I
F
G
Fig. 11
Likely flue positions requiring
a flue terminal guard
Terminal Position with Minimum Distance (Fig. 11)
A* Directly below an openable window, air vent or any other
ventilation opening.
B Below gutter, drain/soil pipe.
C Below eaves.
D Below a balcony/car port roof.
E From vertical drain pipes and soil pipes.
F From internal or external corners.
G Above adjacent ground or balcony level.
H From a surface facing a terminal.
I
Facing a terminals.
J
From opening (door/window) in carport into dwelling.
K Vertically from a terminal on the same wall.
L Horizontally from a terminal on the same wall.
M* Above an opening, air brick, opening window etc.
N* Horizontally to an opening, air brick, opening window etc.
(mm)
300
25
25
25
25
25
300
600
1200
1200
1500
300
300
300
* 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.
Terminal
Assembly
300 min
Top View Rear Flue
Fig. 12
Property Boundary Line
19
7.0 Site Requirements
7.8
Flue Dimensions
The standard horizontal flue kit allows for flue lengths between
100mm and 685mm from elbow to terminal (Fig. 13).
m
5m
68
The maximum permissible equivalent flue length is:
10 metres
m
0m
10
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.
Fig. 13
7.10
Terminal Guard (Fig. 14)
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. 14
20
7.0 Site Requirements
7.11
Flue Options
1. The Baxi Platinum Combi HE can be fitted with flue
systems as illustrated.
B
A
2. The standard flue is suitable only for horizontal
termination applications.
12 11 10
1
9
2
8
3
4
7
5
AM
12 11 10
PM
9
5
1
2
0
8
4
7
3
7
8
4
3
9
1
12 11 10
3
5
PM
2
5
AM
GRASSLIN
2
0
7
4
8
1
3
GRASSLIN
9
2
4
1
2
12 11 10
3
0
1
bar
4
3. Maximum permissible equivalent flue lengths are:-
bar
0
R
Horizontal Concentric
Vertical Concentric
Vertical Twin Pipe
Horizontal
Flues
10 metres
10 metres
15 metres
4. Any additional “in line” bends in the flue system must be
taken into consideration.
Their equivalent lengths are:Concentric Pipes:
45° bend
0.5 metres
93° bend
1.0 metres
Twin Flue Pipe
45° bend
0.25 metres
91.5° bend
0.50 metres
12 11 10
1
9
2
8
3
4
7
5
AM
PM
5
12 11 10
0
9
7
4
1
8
8
3
2
3
9
12 11 10
4
1
3
AM
5
2
7
GRASSLIN
2
PM
5
7
4
1
0
4
8
3
GRASSLIN
9
2
0
bar
12 11 10
3
1
1
2
4
bar
0
The elbow supplied with the boiler is not included in any
equivalent length calculations
R
5. The illustrations opposite show examples of permissible
flue systems.
Vertical
Flues
(Twin Pipe)
6. Instructions for guidance and fitting are included in each
kit, where appropriate.
NOTE: Flue length is measured from point A to B as
shown.
B
A
12 11 10
1
9
2
8
3
4
7
5
AM
PM
5
0
7
4
8
3
GRASSLIN
9
2
12 11 10
3
1
1
2
4
bar
0
12 11 10
1
9
2
8
3
4
7
5
AM
PM
5
0
7
4
8
3
GRASSLIN
9
2
12 11 10
3
1
1
2
4
bar
0
R
R
12 11 10
1
9
2
8
3
4
7
5
AM
PM
5
0
7
4
8
3
GRASSLIN
9
2
12 11 10
3
1
1
2
4
bar
0
R
Vertical
Flues
B
A
12 11 10
1
9
2
8
3
4
7
9
AM
5
12 11 10
1
2
8
7
PM
5
3
AM
5
7
4
4
0
8
3
PM
2
9
5
GRASSLIN
0
7
12 11 10
3
4
1
2
8
3
GRASSLIN
9
12 11 10
3
4
1
1
1
2
2
bar
0
4
bar
0
12 11 10
1
9
2
8
3
4
7
9
5
AM
12 11 10
1
2
PM
8
5
3
0
7
7
4
4
AM
5
8
3
GRASSLIN
1
0
7
4
12 11 10
3
PM
9
2
5
2
8
3
9
2
12 11 10
3
4
1
1
GRASSLIN
2
0
1
bar
4
bar
0
R
R
R
R
21
8.0 Installation
8.1
Initial Preparation
The gas supply, gas type and pressure must be checked for
suitability before connection (see Section 7.4).
145mm
1. After considering the site requirements
(see Section 7.0) position the fixing template on the wall
ensuring it is level both horizontally and vertically.
2. 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 horizontal fixing slots.
3. Mark the position of the centre of the flue hole (rear
exit). For side flue exit, mark as shown (Fig. 16).
For Side Flue Exit
4. Note the shaded area on the template. Pipework may be
routed upwards behind the boiler, providing it does not
conflict with the shaded area.
5. If required, mark the position of the gas and water pipes.
Remove the template.
Fig. 16
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.
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.
8.2
Flushing Tube
Wall Plate
Flushing
1. Connect a tube to the central heating flow or return pipe
(Fig. 17).
2. Flush thoroughly (see System Details, Section 6.2).
8.3
Preparing The Boiler
1. Remove all packaging.
2. Stand the boiler on its base by using the rear lower edge
as a pivot.
Central Heating Return
22
Fig. 17
NOTE: A small amount of water may drain from the
boiler in the upright position.
8.0 Installation
8.4
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.
3. The loop and valves must be connected as shown in the
diagram (Fig. 17a).
Double Check
Valve & Stop Valve
Cold Inlet
4. The two flanged copper elbows supplied are of different
lengths (Fig. 17b). Use pipe ‘A’ to connect to the cold inlet.
Pipe ‘B’ should be used to connect to the central heating
return.
5. Note the orientation of the flow direction arrows on the
stop valve and double check valve.
Fig. 17a
Temporary Filling
Loop
CH Return
Stop Valve
6. Ensure the brass flange nuts are on each pipe and connect
the plain end of pipe ‘A’ to the stop valve inlet and the plain
end of pipe ‘B’ to the outlet of the check valve using the nuts
and washers supplied.
7. Remove the end caps from the isolation taps and put to
one side. Engage the brass flange nuts to the appropriate
connections on the tap rail or pipework. Ensure that the fibre
washers supplied are used on these joints.
Pipe ‘A’
Fig. 17b
To fill, test and flush if required (Fig. 17c)
8. 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 valve.
Pipe ‘B’
9. If desired a suitable gauge can be connected to one of the
taps so that the system may be accurately pressurised.
10. All joints, fittings and system components can now be
examined for soundness at operating pressure.
11. 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.
Pressure
Gauge
12. Remove the blanking plug(s), pressure gauge and flushing
equipment from the appliance if used.
Blanking Plugs
13. Continue with the installation and commissioning.
Hose and
Fitting
14. The filling loop must be disconnected and completely
removed after the system is pressurised.
15. Hand tighten the two previously removed end caps to the
stop valve and double check valve.
Fig. 17c
23
Wall Plate
8.0 Installation
8.5
Fitting The Boiler
1. Remove the sealing caps from the boiler connections.
2. Lift the boiler using the lower edges. Engage the slots at
the top rear of the boiler on the wall plate (Fig. 18).
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.
4. Tighten all the connections.
8.6
Fitting the Pressure Relief Discharge Pipe
(Fig. 19)
1. Remove the discharge pipe from the kit.
Fig. 18
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.
IMPORTANT: Make all soldered joints before connecting
to the pressure relief valve.
8.7
Condensate Drain (see section 7.6)
1. Connect the condensate drain to the trap outlet pipe.
Pressure Relief Valve
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”.
Fig. 19
Discharge Pipe
24
2. The connection will accept 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.
8.0 Installation
8.8
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. 20).
m
5m
68
m
0m
10
2. Locate the flue elbow on the adaptor at the top of the
boiler. Set the elbow to the required orientation (Fig. 21).
NOTE: The flue elbow is angled at 93 degrees to
ensure a fall back to the boiler.
3. Measure the distance from the outside wall face to the
elbow. This dimension will be known as ‘X’
(Fig. 22).
Fig. 20
4. To dimension ‘X’ add 50mm. This dimension to be
known as ‘Y’.
IMPORTANT: Check all dimensions before cutting.
Flue Elbow
Wall Thickness
Adaptor
(X)
Fig. 21
(X)
Wall Thickness
Fig. 20
Fig. 22
25
8.0 Installation
8.8
Waste
Y
Fitting the Flue (Cont)
5. Mark dimension ‘Y’ on the flue as shown (Fig. 23).
Carefully cut the waste material from the flue, ensuring that
the ducts are square and free from burrs.
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.
Flue
Fig. 23
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. 24).
8. Remove the flue elbow and insert the flue through the
hole in the wall. Refit the elbow to the boiler adaptor,
ensuring that it is pushed fully in.
Inner Flue Support Bracket
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. 25).
10. Ensure that the terminal is positioned with the slots to
the bottom (Fig. 25a).
Fig. 24
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 7.9 & 7.10).
Slots at bottom
Fig. 25a
Fig. 25
26
8.0 Installation
8.9
Making The Electrical Connections
To connect the mains input cable proceed as follows: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. 26).
Control Box Cover
3. Remove the control box cover securing screws.
Disengage the barbs on the control box from the cover.
Remove the cover (Fig. 27).
Fig. 27
4. Slacken the cable clamp on the LH side of the boiler
chassis (Fig. 28). Insert the cable through the clamp and
route it to the terminal block.
5. Slacken the screws in the terminal block, connect the
input cable, and tighten the screws.
Fig. 26
Fig. 28
Facia Panel
Cable Clamp
NOTE: Both the Live and Neutral connections are fused.
6. The boiler is fitted with an integral timer. If a room
thermostat is to be connected it can be done at this point.
Run the input cable from the thermostat through the second
cable clamp on the boiler chassis. Refer to the instructions
supplied with the control.
IMPORTANT: The room thermostat MUST be suitable
for 230V switching.
Fuses
Always fit fast
blow 2A fuse
Fused supply 3A
230V ~ 50Hz
NOTE: An external frost thermostat cannot be used
with the integral timer.
Live (brown)
br
Neutral (blue)
b
Earth (green/yellow)
g/y
230V
1
bk
2
bk
8. Ensure that both mains input and, where fitted, external
control input cables have sufficient slack to allow the control
box to drop down. Tighten the cable clamp(s) on the boiler
chassis.
Terminal Block
Fig. 29
L
br
N
b
g/y
230 V
7. Remove the link between terminals 1 & 2. The 230V
supply at terminal 1 can be connected to the thermostat.
The switched output from the thermostat must be
connected to terminal 2. (Fig. 29). If the room thermostat
being used incorporates an anticipator it MUST be wired as
shown in Fig. 29.
1
bk
2
bk
8.10
Preliminary Electrical Checks
1. Prior to commissioning the boiler preliminary electrical
system checks should be carried out.
N
SL
Room Thermostat
2. These should be performed using a suitable meter, and
include checks for Earth Continuity,
Resistance to Earth, Short Circuit and Polarity.
27
9.0 Commissioning
9.1
Commissioning the Boiler
1. Reference should be made to BS 5449 Section 5 when
commissioning the boiler.
Screw
2. Open the mains water supply to the boiler.
3. Open all hot water taps to purge the DHW system.
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 (Fig. 30).
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 then close and disconnect
the filling loop.
Pump
Fig. 30
8. Turn the gas supply on and purge according to in GB BS
6891 and in IE I.S. 813 “Domestic Gas Installations”.
2
9. Test for gas soundness.
1
3
10. Hinge the facia panel upwards and refit the case front
panel. Tighten the securing screws.
4
0
bar
Selector Switch
Display
Pressure Gauge
Fig. 31
2
1
12
11
3
PM
10
GRASSLIN
1
12
4
0
11
28
2
Fig. 32
Domestic Hot Water
Temperature Control
3
Central Heating
Temperature Control
4
9
0
5
bar
AM
8
7
7
8
3
1
9
5
10
4
2
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. 32).
9.0 Commissioning
9.2
Setting the Timer
10
The Electro-Mechanical Timer allows the central heating
system to be set every 15 minutes.
Using the three position switch the timer will allow either
constant operation, timed operation or central heating off.
9
Time Pointer
8
Move the switch button by sliding to the desired position.
Constant
7
Three position switch (Fig. 32a)
Timed
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.
AM
Off
5
0
4
IN
3
Fig. 32a
2
0
Off (Bottom position): No central heating.
Domestic hot water will operate on demand.
Rotate to adjust time
2
1
12
3
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.
11
To set the timed heating program
Decide which times of the day the central heating is required.
AM
8
7
7
8
PM
9
5
10
4
10
9
5
0
The heating will operate when the white tappets are set to
the outer edge of the bezel.
4
GRASSLIN
3
2
1
12
11
4
Timed (Central position): The heating will operate
according to the position of the tappets and be controlled as
above.
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. 32b).
On Position
12
Off Position
11
10
9
Time Pointer
Fig. 32b
29
9.0 Commissioning
9.3
x2
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.
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.
Central Heating
Temperature Control
Fig. 33
3. Ensure that the integral timer and any external controls are
calling for heat, and the selector switch is in the central
heating and hot water position (
). The current boiler
temperature is shown on the display.
Domestic Hot Water
Temperature Control
4. To check the gas rate it is necessary to set the boiler to
‘Calibration Mode’.
Selector Switch
Display
5. Turn both temperature control knobs fully anticlockwise,
then quickly turn the DHW temperature knob 1/4 clockwise
twice and back fully anticlockwise (Fig. 33).
2
1
12
11
3
PM
AM
8
7
7
8
3
1
9
5
10
4
2
1
12
0
11
Domestic Hot Water
Temperature Control
2
4
10
GRASSLIN
3
Central Heating
Temperature Control
4
9
0
5
bar
6. The display will now alternate between ‘SF’ and the
current boiler temperature and both green LEDs will flash
(Figs. 34 & 35).
7. Turn CH temperature control knob fully clockwise. As the
knob is turned the display will change from ‘0’ to ‘00’ (Fig. 36)
indicating maximum rate, then revert to ‘P’ alternating with
the current boiler temperature (Figs 37 & 38).
8. A gas rate measurement may now be made. Approximate
values are:-
Fig. 34
Fig. 35
24 model
2.6 m3/h
28 model
3.1 m3/h
33 model
3.6 m3/h
9. The ‘Calibration Function’ is active for 20 minutes unless
the maximum CH temperature is exceeded.
10. The function can be disabled at any time by turning the
DHW temperature knob.
Fig. 36
Fig. 37
30
Fig. 38
10.0 Completion
10.1
Case Front Panel
Completion
1. Instruct the user in the operation of the boiler and
system including the integral timer, 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. 39
31
11.0 Servicing
11 .1
Case Front Panel
Annual Servicing
1. For reasons of safety and economy, it is recommended that
the boiler is serviced annually.
Servicing must be performed by a competent person.
If a combustion analyser is available the CO2 can be
checked and adjusted - see Section 13.0.
2. After servicing, complete the relevant Service Interval
Record section of the Benchmark Commissioning Checklist at
the rear of this publication.
3. Ensure that the boiler is cool.
4. Ensure that both the gas and electrical supplies to the
boiler are isolated.
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. 40).
Fig. 40
Facia Panel Securing
Screws
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. 41).
7. Unscrew the sump from the bottom of the condensate trap
assembly (Fig. 41a).
8. Remove any deposits from the sump and trap. Clean as
necessary and replace the sump.
Inner Door
Panel
Fig. 41
Condensate
Trap
Sump
Fig. 41a
32
11.0 Servicing
11.1
Burner
Annual Servicing (Cont)
Viewing Window
7. Undo the nut on the gas inlet pipe to the venturi (Fig. 42)
and pull the sensing pipe off the fan.
7.5 ± 1
8. Disconnect the electrode leads, noting their position, and
the fan electrical plugs (Fig. 43).
4 ± 0.5
9. Undo the four nuts retaining the combustion box cover
to the heat exchanger.
Electrode Position
10. Carefully draw the fan, collector and cover assembly
forward, being careful to retain the injector in the venturi
(Figs. 42 & 43).
10 ± 1
11. Clean any debris from the heat exchanger and check
that the gaps between the tubes are clear.
Fan, Collector and Cover
Assembly
12. Inspect the burner, electrodes position and insulation,
cleaning or replacing if necessary. Clean any dirt or dust
from the air box.
13. Reassemble in reverse order.
NOTE: The sensing pipe must be reconnected to the
fan, not the venturi.
Electrode
Leads
DHW Filter (Fig. 45)
14. If the flow of domestic hot water is diminished, it may
be necessary to clean the filter.
Fig. 43
Venturi
15. Initially check the cold water inlet tap filter.
16. Turn the tap off and draw off from a hot tap. Undo the
blanking cap and remove the threaded bush
(Fig. 44).
Injector
Threaded
Fig. 44
Bush
Fig. 42
17. Extract the filter and rinse thoroughly in clean water.
Reassemble and check the flow. If required clean the
restricter filter as described below.
18. Pull off the hall effect sensor. Undo the restricter from
the inlet/return manifold.
Gas Inlet Pipe
19. Rinse the filter thoroughly in clean water and reassemble
in reverse order.
Hall Effect
Sensor
Blanking
Cap
Restricter
Cold Water
Inlet Tap
20. Turn the selector switch fully anticlockwise against the
spring pressure to the reset position and hold for 5 seconds
to reset the boiler.
21. 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.
Hydraulic Inlet
Assembly
Fig. 45
Filter
33
12.0 Changing Components
Bracket
Igniter
Igniter Feed
Plug
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.
See Section 11.1 “Annual Servicing” for removal of case
panel, door etc.
12.1
ElectrodeL
eads
Igniter (Fig. 46)
1. Disconnect the igniter feed plug and the electrode leads,
noting their positions.
Fig. 46
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.
12.2
Spark and Sensing Electrodes (Fig. 47)
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 gaskets and replace if
necessary. Reassemble in reverse order.
Spark
Electrode
ElectrodeL
eads
Sensing
Electrode
Fig. 47
34
12.0 Changing Components
12.3
Fan (Fig. 48)
1. Undo the nut on the gas inlet pipe to the venturi (Fig. 49)
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 extension
piece.
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.
7. Reassemble in reverse order, ensuring that the injector is
in place and the sensing pipe is connected to the fan.
Venturi
Injector
12.4
Venturi (Fig. 48)
1. Remove the collector and fan assembly as described in
section 12.3.
Cover
2. Extract the injector from the venturi.
Gas Inlet Pipe
Fig. 49
3. Undo the screws securing the fan to the venturi and the
venturi to the collector.
IMPORTANT: When fitting the new venturi, ensure the
arrows on it’s base point into the collector (Fig. 50).
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
12.5
Injector (Fig. 48)
Venturi
1. Remove the collector and fan assembly as described in
section 12.3.
Injector
Collector
Fig. 48
2. Extract and replace the injector and reassemble in reverse
order.
Fig. 50
When fitting the venturi
ensure that the arrow is
pointing forward
35
12.0 Changing Components
Cover
12.6
Burner
Burner (Fig. 51)
1. Undo the screws securing the collector to the venturi and
extension piece. Remove this extension piece from the
cover (on 24 and 28 models).
Gasket
Extension Piece
(Not on 33 model)
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
12.7
Insulation (Fig. 52)
1. Remove the electrode leads, noting their positions. Also
remove the electrodes as described in section 12.2.
Collector
Fig. 51
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. 52
Collector
Electrode
Leads
36
Sensing
Electrode
12.0 Changing Components
12.8
Electrical
Plug
Flue/Heat Exchanger
Thermostat Sensor
Flue/Heat Exchanger Thermostat Sensor
(Fig. 53)
1. Ease the retaining tab on the sensor away and disconnect
the electrical plug.
2. Turn the sensor 90o anticlockwise to remove - it is a
bayonet connection.
3. Reassemble in reverse order.
12.9
Fig. 53
Water Pressure Sensor (Fig. 54)
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.
12.10
Central Heating Temperature Sensor (NTC)
(Fig. 54)
1. Ease the retaining tab on the sensor away and disconnect
the electrical plug.
Flow Pipe
2. Unscrew the sensor from it’s pocket and reassemble in
reverse order. The plug will only fit one way.
Central Heating
Temperature Sensor
12.11
Safety Thermostat (Fig. 54)
1. Pull the plug off the 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.
Safety Thermostat
12.12
Pressure Sensor
DHW Temperature Sensor (NTC) (Fig. 55)
1. Turn off the mains cold water supply tap and draw off the
residual domestic hot water.
Fig. 54
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.
Plate Heat
Exchanger
DHW Temperature
Sensor
Fig. 55
37
12.0 Changing Components
12.13
Pump - Head Only (Fig. 56)
1. Drain the 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.
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. 57).
4. Reassemble in reverse order.
12.14
Pump - Complete (Fig. 58)
1. Drain the primary circuit.
Pump Wiring
Cover
2. Undo the two screws securing the body to the pipe and
manifold and draw the pump forwards.
Pump Body
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.
Socket Headed
Screw
4. Unscrew the automatic air vent from the pump body.
5. Connect the wiring to the new pump. Examine the ‘O’
ring seals on the return pipe and manifold, replacing if
necessary.
Pump Head
6. Fit the air vent to the pump body and reassemble in
reverse order.
Fig. 56
12.15
1. Drain the primary circuit and unscrew the automatic air
vent from the pump body.
Pump Setting
Fig. 57
2. Examine the ‘O’ ring seal, replacing if necessary, and fit it
to the new automatic air vent.
Automatic Air
Vent
3. Reassemble in reverse order.
Pump Wiring
Cover
Fig. 58
38
Automatic Air Vent (Fig. 58)
12.0 Changing Components
12.16
Gauge Retaining
Bracket
Pressure Gauge (Figs. 59 & 60)
1. Drain the primary circuit and undo the nut on the
pressure gauge capillary.
2. Undo the screws securing the gauge retaining bracket.
Pressure Gauge
Fig. 60
3. Remove the bracket and gauge assembly. Depress the
barbs on the side of the gauge and remove the retaining
bracket.
4. Examine the sealing washer, replace if necessary.
5. Reassemble in reverse order.
12.17
Hall Effect Sensor (Fig. 61)
1. Ease the sensor upwards off the hydraulic inlet manifold
assembly.
2. Disconnect the electrical plug from the sensor.
Fig. 59
Pressure Gauge
Capillary
Hall Effect
Sensor
3. Connect the plug to the new sensor. Carefully fit the new
sensor to the hydraulic assembly, ensuring it is fully down.
12.18
Pressure Relief Valve (Fig. 62)
1. Drain the 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. 61
‘O’ ring seal
Grub Screw
Pressure Relief Valve
Fig. 62
Discharge Pipe
39
12.0 Changing Components
12.19
Plate Heat Exchanger (Fig. 63)
1. Drain the primary circuit and remove the gas valve as
described in section 12.23.
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. 63
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.
12.20
Diverter Valve - Motor Unit & Assembly
(Figs. 64 & 65)
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. 64
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.
Bypass Pipe
Spring Clip
Securing Screw
40
Fig. 65
12.0 Changing Components
12.21
P.C.B. (Fig. 67)
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. 65).
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
Fig. 66
P.C.B.
5. Reassemble in reverse order, ensuring that the
temperature controllers are reset to their previous positions.
12.22
Selector
Switch
Selector Switch (Fig. 67)
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. 66).
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. 67
41
12.0 Changing Components
12.23
Venturi Inlet
Pipe
Outlet Adaptor
Gas Valve (Fig. 68)
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.
Gas Valve
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.
5. Remove the outlet adaptor and inlet pipe and transfer them
to the new valve. Examine the ‘O’ ring seals, replace if
necessary.
Ignition Lead
6. Reassemble in reverse order.
IMPORTANT: The CO2 must be checked and adjusted as
detailed in Section 13.0 Combustion Check
Valve
Inlet Pipe
12.24
Expansion Vessel (Fig. 69)
1. Drain the primary circuit and undo the nut on the vessel
connection pipe.
Gas Feed
Elbow
2. Undo and remove the locknut and spring washer securing
the vessel spigot to the boiler air box.
Fig. 68
3. Remove the bracket and vessel from the boiler.
Retaining Bracket
4. Locate the retaining bracket on the upper flange of the
vessel and fit to the boiler.
Expansion Vessel
Boiler Chassis
Spring
Washer
Lock Nut
Fig. 69
42
5. Reassemble in reverse order.
13.0 Combustion Check
x2
13.1
Checking the CO2
1. The combustion (CO2) may be checked using a suitably
calibrated analyser after running the boiler for several
minutes.
2. To do this it is necessary to set the boiler to ‘Calibration
Mode’.
Central Heating
Temperature Control
3. Ensure that all external controls are calling for heat. The
actual current boiler temperature is shown on the display.
Domestic Hot Water
Temperature Control
Fig. 70
4. Turn both temperature control knobs fully anticlockwise,
then quickly turn the DHW temperature knob 1/4 clockwise
twice and back fully anticlockwise (Fig. 70).
Display
Selector Switch
2
1
12
11
3
PM
10
GRASSLIN
3
2
1
12
4
0
11
Central Heating
Temperature Control
4
9
0
5. The display will now alternate between ‘SF’ and the
current boiler temperature and both green LEDs will flash
(Figs. 71 & 72).
5
bar
AM
8
7
7
8
3
1
9
5
10
4
2
6. Turn the CH temperature knob fully clockwise. As the
knob is turned the display will change, indicating the fan
speed.
Domestic Hot Water
Temperature Control
7. The display will show ‘00’, indicating maximum rate, then
revert to ‘P ‘ alternating with the current boiler temperature
(Figs 73, 74 & 75).
8. Remove the plug from the flue adaptor test point. Insert
the analyser probe and allow time for the reading to settle
(Fig. 76).
The CO2 should be 8.7% ± 0.2
Fig. 72
Fig. 71
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. 77).
Fig. 74
Fig. 73
Fig. 75
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.
Flue Adaptor Test
Point
Plug
11. With the boiler on minimum, the ‘Min. Rate’ adjustment
screw must be altered, using a suitable hexagon key, after
removing the cap (Fig. 77). If the CO2 is reset at either
boiler rate it must be rechecked at the other rate and also
adjusted if required.
Analyser Probe
Fig. 76
Min Rate
Adjustment Screw
(cap fitted)
Max Rate
Adjustment Screw
(cover removed)
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. 77
43
14.0 Electrical
14.1
Central Heating
NTC Sensor
DHW
NTC Sensor
Illustrated Wiring Diagram
b
b
Overheat Stat
Hall Effect
Sensor
b
r
Water Pressure
Switch
b
r
Flue Sensor
1
4
2
g
br
r
5
b
w
b
g
g
bk
Fan
3
1
2
b
b
b
g/y
br
X400
1
X401
9 87 6 5 4 3 2 1
2
3
4
10 9 8 7 6 5 4 3 2 1
4
bk
3
br
2
Control PCB
bk
1
Timer
b
X9
X501
1
2
1
X1
2
3
4
1
5
X2
2
3
4
5
6
7
8
9
r
bk
X3
b
br
Flame
Sensing
Electrode
br
br
br
b
b
Pump
w
bk
b
br
b
r
br
b
w
r
L
Spark
Generator
N
bk
b
Mains Input
Link
b
a
g/y
Diverter Valve
br
b
br
g
w
bk
Gas Valve
br
Ignition
Electrode
br
b
r
b
Reset Selector Switch
bk
br
bk
b
w
44
- brown
- black
- blue
- white
g - green
g/y - green / yellow
r
- red
15.0 Short Parts List
Short Parts List
Key
No.
Description
Manufacturers
Part No.
426
306
315
G.C.
No.
311
Fan
5114684
426
Motor 3way Valve
248733
315
Igniter Electrode
5114702
316
Sensing Electrode
5114703
422
Gas Valve
5114734
624
Hall Effect Sensor
5114767
316
311
306
Burner 24/28
5114697
Burner 33
5114698
419
Water Pressure Switch
5114748
400
Plate Heat Exchanger
5114708
415
Pump
248042
302
Flue Thermostat
5114747
421
NTC Sensor
5114725
420
Overheat Thermostat
5114729
504
Pressure Gauge
248090
419
624
422
503
400
PCB 24
5116024
PCB 28
5115062
PCB 33
5114745
415
302
503
421
420
504
45
16.0 Fault Finding
16.1
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.
Initial Fault Finding Checks
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.
16.2
Error Codes
1. If a fault occurs on the boiler an error code may be shown
by the facia display.
Table Of Error Codes
E20
E50
E28
E110
E119
E125
E130
E133
E160
Central Heating NTC Fault
Flue NTC Fault
Hot Water NTC Fault
Safety Thermostat Operated
Water Pressure Switch Not Operated
Pump Fault
Flue NTC Operated
Interruption Of Gas Supply or Flame Failure
Fan or Fan Wiring Fault
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'
E20, E28 & E50 indicate faulty components.
E110 shows overheat of the primary water and E130
overheat of the flue system.
E119 is displayed when the primary water pressure is less
than 0.5 bar.
E133 indicates that the gas supply has been interrupted,
ignition has failed or the flame has not been detected.
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 the pump is probably inoperative.
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.
46
16.0 Fault Finding
Refer to Section 14.0 “Illustrated Wiring Diagram” for position of terminals and components
Central Heating - Follow operational sequence
Turn selector switch to
The display illuminates
NO
Go to section ‘A’
YES
Error 110 flashing
Error 130 flashing
Error 133 flashing
YES
Turn the selector switch to
reset position for 5 seconds
YES
If the error 110 is still flashing.
Go to section ‘J’
NO
Error 20, 28 or 50 flashing
YES
Go to section ‘E’
NO
YES
Error 119 flashing
Go to section ‘C’
Ensure controls are set to
demand and verify the
contacts are closed
NO
NO
Turn Central Heating
thermostat to Maximum.
Pump runs
NO
Ensure all controls and
integral clock are calling for
heat
YES
Error 125 flashing
Go to section ‘B’
YES
3-way valve is open to Central
Heating circuit
NO
Go to section ‘K’
YES
Fan runs
NO
Error 160 flashing
Go to section ‘D’
NO
Error 160 flashing
Go to section ‘L’
YES
Fan runs at correct speed
YES
Spark at ignition electrodes for
up to 5 seconds and for 3
attempts
YES
NO
Error 133 flashing
YES
Go to section ‘H’
Turn the selector switch to
reset
Go to section ‘F’
NO
YES
Burner lights
Burner does not stay alights
after 5 seconds
YES
Error 133 flashing
Go to section ‘I’
YES
Pump continues to run for 3
minutes
(room thermostat open)
Check the Central Heating
NTC sensor
Go to section ‘E’
YES
NO
Burner output modulates to
maintain the temperature set
Error 130 flashing
Go to section ‘M’
YES
Burner goes out
YES
Fan stops after 10 seconds
YES
Operation sequence
successful
47
16.0 Fault Finding
Domestic Hot Water - Follow operational sequence
Turn selector switch to
The display illuminates
NO
Go to section ‘A’
YES
Error 110 flashing
Error 133 flashing
YES
Turn the selector switch to
reset position for 5 seconds
YES
If the error 110 is still flashing.
Go to section ‘J’
NO
YES
Error 20, 28 or 50 flashing
Go to section ‘E’
NO
YES
Error 119 flashing
Go to section ‘C’
Go to section ‘B’
NO
Turn Domestic Hot Water
thermostat to Maximum.
Open DHW tap fully.
DHW Hall Effect sensor
operated (red neon on the
sensor illuminated
YES
NO
DHW flow rate more than 2
l/min
YES
YES
NO
3-way valve is open to
Domestic Hot Water circuit
Is mains water filter and
assembly clean?
Is the magnetic detector free
to move in the Hall Effect
sensor
Go to section ‘K’
YES
Pump runs
NO
Error 125 flashing
Go to section ‘B’
NO
Error 160 flashing
Go to section ‘D’
NO
Error 160 flashing
Go to section ‘L’
YES
Fan runs
YES
Fan runs at correct speed
YES
Spark at ignition electrodes for
up to 5 seconds and for 3
attempts
YES
NO
Error 133 flashing
YES
Go to section ‘H’
Turn the selector switch to the
reset position for 5 seconds
Go to section ‘F’
NO
Burner lights
YES
Burner does not stay alights
after 5 seconds
YES
Error 133 flashing
Go to section ‘I’
NO
Reduce DHW flow rate
Burner modulates
NO
Clean DHW NTC sensor
and DHW heat exchanger
YES
Burner output modulates to
maintain the temperature set
YES
NO
Error 130 flashing
Go to section ‘M’
Close DHW tap
YES
DHW flow sensor senses no
flow. Burner goes out
48
YES
Fan stops after 10 seconds
YES
Pump runs for 30 seconds
YES
Operation sequence
successful
16.0 Fault Finding
Fault Finding Solutions Sections
A
Is there 230V at:
1.
Main terminals L and N
2.
Main terminal fuse
3.
B
NO
Check electrical supply
NO
Replace fuse
NO
Check wiring
PCB - X1 connector
terminals 1,2
NO
Display
illuminated
Replace PCB
Is there 230V at:
YES
1.
Pump
2.
PCB - X3 connector terminals 3 & 4
NO
If pump jammed, release
NO
Replace pump
Replace PCB
YES
Change pump supply cable
C
1.
YES
CH system pressure less than 0.5 bar
NO
2.
D
1.
Check the tap of the automatic air
vent is opened
Fan connections correct at fan. PCB X2 connector, is 230V AC across
terminals 5 & 7
Re-pressurise system
Check connection water pressure
switch terminal
COM - NO and PCB connector
X400 terminals 3,4
NO
YES
YES
Replace water
pressure switch
Open the automatic air vent
Fan jammed or faulty winding
YES
Replace fan
NO
Replace PCB
49
16.0 Fault Finding
E
F
Temperature sensors faulty.
Cold resistance approximately
10kΩ @ 25° C (DHW and CH sensors)
20kΩ @ 25° C (Flue sensor)
(resistance reduces with increase in temp.)
1.
2.
NO
Replace sensor
Check and correct the connection of the
tube between the venturi and gas valve
Gas at burner
NO
Ensure gas is on and purged
PCB - X3 connector is 230V AC across
terminals 1 & 2
YES
Replace gas valve
NO
Replace PCB
G
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
H
Check and correct if necessary
1. Ignition electrode and lead
2. Electrode connection
3. Spark gap and position
Replace Hall
Effect Sensor
NO
YES
voltage at PCB - X2 connector is
230V AC across terminals 2,5
Check wiring
Replace PCB
YES
Burner
Viewing Window
7.5 ± 1
4 ± 0.5
Electrode Position
50
10 ± 1
Replace igniter
16.0 Fault Finding
I
1.
2.
Check the gas supply pressure:
For Natural Gas greater than
10 - 11 mbar
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
Flame current should be more than 0.5 μA
J
1.
Overheat thermostat operated or
faulty, i.e. continuity across
thermostat terminals
NO
NO
Replace PCB
Replace flame sensing electrode
Allow to cool. Continuity
across thermostat terminals
more than 1.5 ohm
YES
Replace safety thermostat
YES
Replace PCB
K
Is there 230V at:
1.
Motor 3-way valve
2.
PCB - X3 connector terminals
5 & 6 central heating mode
5 & 7 domestic hot water mode
YES
Replace motor 3-way valve
NO
Replace PCB
YES
Change pump supply cable
L
1.
M
1.
Fan connections correct at fan.
PCB - X401 connector terminals 5,6,7 & 8
Temperature sensors faulty.
Cold resistance approximately
10kΩ @ 25° C (CH sensor)
20kΩ @ 25° C (Flue sensor)
(resistance reduces with increase in temp.)
YES
NO
YES
2.
If pump is running the heat exchanger could be
obstructed
Replace fan
Replace sensor
Replace heat exchanger
51
17.0 Notes
52
17.0 Notes
53
BENCHMARK
No. 5 1 1 6 2 8 0
1.0 Introduction
GAS BOILER COMMISSIONING CHECKLIST
COLLECTIVE MARK
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
PROGRAMMABLE ROOMSTAT
CYLINDER T/STAT & PROGRAMMER/TIMER
COMBI BOILER
HEATING ZONE VALVES
FITTED
NOT REQUIRED
HOT WATER ZONE VALVES
FITTED
NOT REQUIRED
THERMOSTATIC RADIATOR VALVES
FITTED
AUTOMATIC BYPASS TO SYSTEM
FITTED
TIME & TEMPERATURE CONTROL TO HOT WATER
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
BURNER OPERATING PRESSURE (IF APPLICABLE)
N/A
ft3/hr
mbar
CENTRAL HEATING FLOW TEMPERATURE
°C
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
GAS RATE
m3/hr
N/A
MAXIMUM BURNER OPERATING PRESSURE (IF APPLICABLE)
ft3/hr
mbar
COLD WATER INLET TEMPERATURE
°C
HOT WATER OUTLET TEMPERATURE
°C
WATER FLOW RATE
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
1
54
SIGN
CORGI ID No.
DATE
1
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
SERVICE 2 DATE
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
SIGNATURE
SIGNATURE
SERVICE 3 DATE
SERVICE 4 DATE
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
SIGNATURE
SIGNATURE
SERVICE 5 DATE
SERVICE 6 DATE
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
SIGNATURE
SIGNATURE
SERVICE 7 DATE
SERVICE 8 DATE
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
SIGNATURE
SIGNATURE
SERVICE 9 DATE
SERVICE 10 DATE
ENGINEER NAME
COMPANY NAME
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
ENGINEER NAME
COMPANY NAME
SIGNATURE
SIGNATURE
TEL No.
CORGI ID CARD SERIAL No.
COMMENTS
55
924.355.1
B a x i H e a ting UK Limited
Brownedge Road Bamber Bridge Preston Lancashire PR5 6UP
After Sales Service 08700 60 30 60 Technical Enquiries 08706 049 049
Website www.baxi.co.uk
company
Comp No 5116280 - Iss 2 - 11/05