Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
On/Off Switch ON
Gain access to bottom of PCB
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
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:
Test 1 - No demand
Measure the DC voltage between terminal 6 (the red wire location when plug is fitted) of the PCB fan connector and a suitable earth.
Expect a voltage of approximately 13.5 Vdc.
Test 2 - With demand
Apply a CH demand.
Repeat the above test.
Expect the voltage to have dropped to approximately 0 Vdc as the PCB attempts to send power to the fan.
Measure the DC voltage between terminal 6 (the red wire location when plug is fitted) of the PCB fan connector and a suitable earth.
Expect a voltage of approximately 13.5 Vdc.
Test 2 - With demand
Apply a CH demand.
Repeat the above test.
Expect the voltage to have dropped to approximately 0 Vdc as the PCB attempts to send power to the fan.
Isolate as per TOPs P4
and refit as necessary