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:
Allow fan to run.
Measure the DC voltage between the white wire at M3 to the blue wire at M6 on the main PCB.
Voltage should be approximately 35V DC.
Measure the DC voltage between the white wire at M3 to the blue wire at M6 on the main PCB.
Voltage should be approximately 35V DC.
Isolate as per TOPs P4
and refit as necessary