Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to AC Volts 
Gain access to PCB (use Insulation Mat as required)
Central Heating Switch in Constant position
Room thermostat calling for heat (if fitted)
Note:
If no external room thermostat is fitted a link between terminals 3 & 4 (L & Swl) of the mains power supply terminal block should be fitted
Central Heating Switch in Constant position
Room thermostat calling for heat (if fitted)
Note:
If no external room thermostat is fitted a link between terminals 3 & 4 (L & Swl) of the mains power supply terminal block should be fitted
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Is there mains voltage present on connector PL1 connection 3 (white wire) and connection
8 neutral (blue wire)?
8 neutral (blue wire)?
Isolate as per TOPs P4
and refit as necessary