Set Appliance State:
Set Multimeter to DC Volts 
CH Demand
Isolate Mains Power to appliance as per TOPs P4
Gain access to bottom of PCB
(This may require unclipping from main bracket)
Remove the fan connector from the PCB
Note:
Ensure PCB is located safely before turning the power back ON
Gain access to bottom of PCB
(This may require unclipping from main bracket)
Remove the fan connector from the PCB
Note:
Ensure PCB is located safely before turning the power back ON
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure the DC voltage between terminal 4 (the blue wire location when plug is fitted) of the PCB fan connector and a suitable earth. The fan connection is at the bottom left hand side of the PCB.
Expect a voltage of approximately 75 vdc 5 seconds after power is reinstated as the PCB attempts to send power to the fan.
Note:
Shortly before the fault code is shown the voltage will increase to 110 vdc, reset the boiler as necessary until the result of the test can be ascertained.
Expect a voltage of approximately 75 vdc 5 seconds after power is reinstated as the PCB attempts to send power to the fan.
Note:
Shortly before the fault code is shown the voltage will increase to 110 vdc, reset the boiler as necessary until the result of the test can be ascertained.
Isolate as per TOPs P4
and refit as necessary