Set Appliance State:
Set Multimeter to AC Volts 
CH Demand
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Reset boiler if required.
Allow fan to run and ignition sequence to commence.
Measure the voltage at connector CN1 second from bottom (brown wire) on control PCB to a suitable neutral.
Approximately 8 seconds after the fan starts mains voltage should be present for 3 to 5 seconds. This should repeat 5 times before boiler locks out, with approximately 5 seconds between attempts.
Note:
Reset boiler as required until test is complete.
Allow fan to run and ignition sequence to commence.
Measure the voltage at connector CN1 second from bottom (brown wire) on control PCB to a suitable neutral.
Approximately 8 seconds after the fan starts mains voltage should be present for 3 to 5 seconds. This should repeat 5 times before boiler locks out, with approximately 5 seconds between attempts.
Note:
Reset boiler as required until test is complete.
Isolate as per TOPs P4
and refit as necessary