Set Appliance State:
Mains Power Off
Set Boiler Control Thermostat to MAX position
Set Multimeter to AC Volts 
CH Demand
External controls calling for heat
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Allow ignition sequence to commence and burner to establish.
Remove heating demand.
Measure the voltage across the pump live (connection marked P) and the pump neutral (connection marked PN) on the main connector block.
Mains voltage should be present for approximately 5 minutes after the demand for heating has been removed.
Remove heating demand.
Measure the voltage across the pump live (connection marked P) and the pump neutral (connection marked PN) on the main connector block.
Mains voltage should be present for approximately 5 minutes after the demand for heating has been removed.
Isolate as per TOPs P4
and refit as necessary