Set Appliance State:
Mains Power Off
Set Multimeter to DC Volts 
Turn Hot Water Tap On
Use insulation mat as necessary
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Allow pump to run.
Measure voltage across connection 2 (yellow lead) and connection 3 (blue lead) on the three connection connector nearest the front of the appliance on the fan control PCB.
Expected voltage greater than 1 volt DC.
Notes:
1. This is best done at the exposed area of the pins at the back of the connector as it comes off of the fan board.
2. Voltage will only be present for approximately 5 seconds, if boiler locks out you will need to switch the boiler off/on to continue test.
Measure voltage across connection 2 (yellow lead) and connection 3 (blue lead) on the three connection connector nearest the front of the appliance on the fan control PCB.
Expected voltage greater than 1 volt DC.
Notes:
1. This is best done at the exposed area of the pins at the back of the connector as it comes off of the fan board.
2. Voltage will only be present for approximately 5 seconds, if boiler locks out you will need to switch the boiler off/on to continue test.
Isolate as per TOPs P4
and refit as necessary