Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Turn Hot Water Tap On
Gain access to PCB (use Insulation Mat as required)
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Reset appliance if required (press reset button once and release).
Measure for DC voltage between pin 9 (blue) on connector X20
and the earth point on the boiler chassis.
When the fan starts, approximately 16 - 22 Vdc should be present for 4 seconds, this will then be present again after approximately 6 seconds. This will be repeated 5 times before lockout occurs, reset as required until test complete.
Note:
1. Ensure a good connection is made or misdiagnosis will occur.
2. Each pin on the PCB connector is numbered.
Measure for DC voltage between pin 9 (blue) on connector X20
and the earth point on the boiler chassis.
When the fan starts, approximately 16 - 22 Vdc should be present for 4 seconds, this will then be present again after approximately 6 seconds. This will be repeated 5 times before lockout occurs, reset as required until test complete.
Note:
1. Ensure a good connection is made or misdiagnosis will occur.
2. Each pin on the PCB connector is numbered.
Isolate as per TOPs P4
and refit as necessary