Set Appliance State:
Set Multimeter to DC Volts 
Isolate Mains Power to appliance as per TOPs P4
Ensure the boiler is cool so that there is demand for preheat
Set DHW temperature selector to ECO
Remove control box rear cover to expose main PCB
Ensure the boiler is cool so that there is demand for preheat
Set DHW temperature selector to ECO
Remove control box rear cover to expose main PCB
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Allow ignition sequence to commence.
Test for DC voltage between connection 4 (brown wire)
on H5 at the PCB and a suitable earth.
Observe voltage as ignition sequence progresses.
At rest expect reading of Approx 77 VDC, during ignition attempts Voltage will increase to Approx 170 VDC.
When flame is present expect voltage to drop to Approx 10-20 VDC.
Note:
Ensure that spark generator is correctly mounted and secured to the heat exchanger bracket. If incorrectly fitted it has been found to affect rectification.
Test for DC voltage between connection 4 (brown wire)
on H5 at the PCB and a suitable earth.
Observe voltage as ignition sequence progresses.
At rest expect reading of Approx 77 VDC, during ignition attempts Voltage will increase to Approx 170 VDC.
When flame is present expect voltage to drop to Approx 10-20 VDC.
Note:
Ensure that spark generator is correctly mounted and secured to the heat exchanger bracket. If incorrectly fitted it has been found to affect rectification.
Isolate as per TOPs P4
and refit as necessary