Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Gain access to PCB (use Insulation Mat as required)
ECO mode ON
Appliance in WINTER mode (no picture of a sun in the display press reset button to toggle picture of sun on and off)
ECO mode ON
Appliance in WINTER mode (no picture of a sun in the display press reset button to toggle picture of sun on and off)
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Allow fan purge to complete (2 minutes), allow the burner to ignite and boiler to run in CH mode.
Measure the dc voltage between pin 3 and pin 4 connector X4 with the burner lit (voltage should be approximately 210 vdc).
Put the appliance into summer mode (press the reset button once a sun will appear in the display) while continuing to monitor the voltage.
As soon as the demand ends the voltage should return to approximately 0 vdc.
Does the voltage behave as described above?
Measure the dc voltage between pin 3 and pin 4 connector X4 with the burner lit (voltage should be approximately 210 vdc).
Put the appliance into summer mode (press the reset button once a sun will appear in the display) while continuing to monitor the voltage.
As soon as the demand ends the voltage should return to approximately 0 vdc.
Does the voltage behave as described above?
Isolate as per TOPs P4
and refit as necessary