Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Remove plastic top cover from Gas Valve
(Held by one screw in the top R/H corner of the cover)
Disconnect black leads from the terminals of the Gas Valve Operator
(These are the two separate leads, not the plug connector on the Modulating Solenoid)
(Held by one screw in the top R/H corner of the cover)
Disconnect black leads from the terminals of the Gas Valve Operator
(These are the two separate leads, not the plug connector on the Modulating Solenoid)
Measurement:
Measure the resistance across the exposed terminals of the Gas Valve Operator.
Resistance should be approximately 200 Ohms.
Resistance should be approximately 200 Ohms.
Isolate as per TOPs P4
and refit as necessary