Set Appliance State:
Gas Off
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to AC Volts 
CH Demand
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Boiler switch On.
Reset lockout as necessary.
Allow fan to run after approximately 8 seconds.
Measure voltages across connections 22 (black lead) and connection 23 (orange lead) on connector marked X7 on the PCB.
Expected voltage mains voltage (230 volts AC).
Reset lockout as necessary.
Allow fan to run after approximately 8 seconds.
Measure voltages across connections 22 (black lead) and connection 23 (orange lead) on connector marked X7 on the PCB.
Expected voltage mains voltage (230 volts AC).
Isolate as per TOPs P4
and refit as necessary