VOLTAGE FAN SWITCHED

Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4

Set Multimeter to AC Volts

Turn Hot Water Tap On

On/Off Switch Off
Attach black probe to an earth point with crocodile clip
Ensure fan connector is attached to PCB
Disconnect connector from the fan assembly and make safe

WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure

Mains Power On

Measurement:

Place red probe over terminal 2 in preparation for monitoring the AC voltage.
On/Off Switch On, Reset boiler as required.
As the boiler carries out its initialisation check (P2 - P3 - P4 shown on display) note the voltage between terminal 2 (fan connector) and boiler earth. After the boiler finishes its initialisation check (Flow temperature shown on display) the AC voltage should increase by approximately 2.0V AC or greater from the voltage during initialisation.
You will probably need to repeat test several times to confirm test results.

1 2 3 4 5

Note:
For ease of access it may be advisable to remove pump plugs from PCB. Care should be taken not to short terminals with probes. The fan connector may need to be slid down off the PCB slightly but should remain in contact with the PCB terminals. Voltage increase will only occur whilst the appliance is not in lockout.