Set Appliance State:
Gas Off
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
CH Demand
ON/OFF Switch in ON Position
CH Temp Selector in Maximum position
DHW Temp Selector in Minimum position
Mode Selector Switch in Heat and Hot water position
Remove plastic top cover from gas valve
(held by one screw top R/H corner of the cover)
CH Temp Selector in Maximum position
DHW Temp Selector in Minimum position
Mode Selector Switch in Heat and Hot water position
Remove plastic top cover from gas valve
(held by one screw top R/H corner of the cover)
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
If required reset boiler, turn CH / DHW control to reset position.
Allow Fan to run and ignition sequence to commence.
Measure the Voltage across the two black leads on the Gas Valve Operator.
(These are the two leads towards the R/H side of the Valve, not the black leads on the Modulating Solenoid).
Voltage should be approximately 20 Volts DC.
Allow Fan to run and ignition sequence to commence.
Measure the Voltage across the two black leads on the Gas Valve Operator.
(These are the two leads towards the R/H side of the Valve, not the black leads on the Modulating Solenoid).
Voltage should be approximately 20 Volts DC.
Isolate as per TOPs P4
and refit as necessary