Manual

21
221691B
Diagram 10.1
ELECTRICAL FAULT FINDING
FUNCTIONAL FLOW WIRING
Diagram 10.2
10 Fault Finding - Electrical
0899
THERMOSTAT
GAS VALVE
CONTROL
SOLENOID
L
N/C
C
N
ORANGE
RED
BLUE
3
4
0900
Isolate electricity supply to the control box. Remove the control box cover and physically check all cables
and connections.
With electricity supply isolated, remove the cover of the mains inlet connector. Replace the connector without
cover. Restore electricity supply. Is voltage between C and N (blue) 220 to 240V ~ ?
Isolate electricity supply and re-connect red cable.
Restore the supply.
Isolate electricity supply to the control box.
Disconnect red cable at C. Restore electricity
supply. Is voltage between red cable connector
and N (blue) 220 to 240V ~ ?
Turn boiler thermostat to 'MAX'. Is voltage between
N/C and N (blue) 220 to 240V ~ ?
Faulty red cable or connection, isolate electricity
supply and renew cable.
Faulty thermostat, isolate electricity supply
and renew thermostat.
Faulty orange cable or connection, isolate
electricity supply and renew cable.
Faulty blue cable or connection, isolate electricity
supply and renew cable.
Faulty gas valve, isolate electricity
supply and renew valve.
Turn boiler thermstat to 'O'. Is voltage between N/C and
N (blue) zero ?
Isolate electricity supply. Disconnect orange cable at gas
valve. Restore electricity supply and turn boiler thermostat
to 'MAX'. Is voltage between orange cable connector and
N (blue) 220 to 240V ~ ?
Isolate electricity supply. Disconnect blue cable at gas
valve. Replace cover of mains inlet connector.
Restore electricity supply. Is voltage between orange
and blue cable connectors 220 to 240V ~ ?
Isolate electricity supply. Re-connect orange and blue
cables to gas valve. Restore electricity supply.
With pilot burner lit and boiler thermostat set between
'MIN' and 'MAX', does the main burner light?
Turn boiler thermostat to 'O'.
Does main burner extinguish?
Boiler controls in order.
START Carry out preliminary electrical checks to make sure that the electricity supply is available at the boiler.
Check that any remote time or temperature controls are calling for duty. Make sure that the system is filled,
the gas supply is available and the pilot is lit.
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
YES
10.1 Electrical
Refer to electrical fault finding chart, diagram 10.1, functional
flow diagram 10.2 and wiring diagram 9.2.
IMPORTANT: The preliminary electrical system checks as
contained in the British Gas Multimeter Instruction Book, or
similar publication, are the first checks to be carried out during
a fault finding procedure. On completion of the service fault
finding task which has required the breaking and remaking of
electrical connections, then the checks, earth continuity, polarity
and resistance to earth must be repeated.