Set Appliance State:
Gas Off
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Turn Hot Water Tap On
Boiler ON/OFF Switch OFF
CH Temperature Selector OFF
DHW Temperature Selector to Max
Remove lower front facia panel
CH Temperature Selector OFF
DHW Temperature Selector to Max
Remove lower front facia panel
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Boiler ON/OFF Switch ON.
Measure Voltage across connection 1 (grey wire) and connection 2 (white wire) at connector marked X1 on the pump control PCB.
Measure Voltage across connection 1 (grey wire) and connection 2 (white wire) at connector marked X1 on the pump control PCB.
Isolate as per TOPs P4
and refit as necessary