Set Appliance State:
Mains Power Off
Set Multimeter to AC Volts 
CH Demand
DHW Selector in Minimum (-) position
CH Selector in Maximum (+) position
ON/OFF Switch in ON position
DHW Selector in Minimum (-) position
CH Selector in Maximum (+) position
ON/OFF Switch in ON position
Ensure the external controls (if fitted) are calling for heat
Turn the clock override switch to the 'I' position
Turn the clock override switch to the 'I' position
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Measure the voltage between pin 2 connector X1A (orange wire) and pin 2 connector X1B (blue wire).
Note:
If external controls are not fitted ensure the link is in place in the power plug located underneath the appliance.
Expect mains voltage.
Note:
If external controls are not fitted ensure the link is in place in the power plug located underneath the appliance.
Expect mains voltage.
Isolate as per TOPs P4
and refit as necessary