Set Appliance State:
Set Boiler Control Thermostat to MAX position
Set Multimeter to AC Volts 
DHW Demand
Isolate Mains Power to appliance as per TOPs P4
Ensure external controls are calling for heat
Use insulation mat as required
Ensure external controls are calling for heat
Use insulation mat as required
Gas On
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Allow fan to run and burner to ignite.
Wait until the boiler has prematurely shut down.
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 the boiler has prematurely shut down.
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