Set Appliance State:
Mains Power Off
Set Multimeter to DC Volts 
Turn Hot Water Tap On
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure the voltage across the black lead connection 1 and the white lead connection 3 on the 5 way connector on the fan control board (connections numbered from the top)
Observe voltage.
After approximately 8 seconds does the voltage reading pulse high then low?
There will be approximately 4 seconds between pulses.
Expected readings high 30-35 Volts DC, low 0-5 Volts DC.
Observe voltage.
After approximately 8 seconds does the voltage reading pulse high then low?
There will be approximately 4 seconds between pulses.
Expected readings high 30-35 Volts DC, low 0-5 Volts DC.
Isolate as per TOPs P4
and refit as necessary