Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Use Insulation Mat as required
Disconnect connector from the fan and make safe
Disconnect connector from the fan and make safe
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure the voltage between the red wire (pin 17) on the connector marked X20 and a suitable earth.
Voltage should be approximately 22vdc.
Voltage should be approximately 22vdc.
Isolate as per TOPs P4
and refit as necessary