Set Appliance State:
Set Boiler Control Thermostat to MAX position
Set Multimeter to AC Volts 
CH Demand
Isolate Mains Power to appliance as per TOPs P4
Ensure external control are calling for heat
Use insulation mat as required
Ensure external control are calling for heat
Use insulation mat as required
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Allow the boiler to ignite and run.
Wait until it has shut down prematurely.
Measure the voltage across the switched live connection (marked SwL, red wire) and the neutral connection (marked N, blue wire) at the terminal block.
Mains voltage expected.
Wait until it has shut down prematurely.
Measure the voltage across the switched live connection (marked SwL, red wire) and the neutral connection (marked N, blue wire) at the terminal block.
Mains voltage expected.
Isolate as per TOPs P4
and refit as necessary