Set Appliance State:
Gas Off
Set Multimeter to AC Voltage 
CH Demand
Isolate Mains Power to appliance as per TOPs P4
Rotary Switch in CH and DHW position
CH Thermostat adjusted to Maximum
Ensure the Boiler has not reached its operating temperature
Keep Boiler Case Switch depressed
Remove the 0.25 Amp fuse, insert the positive probe into the fuse holder
Rotary Switch in CH and DHW position
CH Thermostat adjusted to Maximum
Ensure the Boiler has not reached its operating temperature
Keep Boiler Case Switch depressed
Remove the 0.25 Amp fuse, insert the positive probe into the fuse holder
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Measure the voltage across the fuse holder base and the neutral (Blue wire terminal marked N) on the main terminal block.
Note:
Ensure probe has good contact with base of fuse holder.
Note:
Ensure probe has good contact with base of fuse holder.
Isolate as per TOPs P4
and refit as necessary