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:
Test 1:
Measure the resistance across the exposed terminals
of the Gas Valve Operator.
Resistance should be approximately 200 Ohms.
Test 2:
Measure the resistance across one exposed terminal
of the gas valve operator and a suitable earth connection.
Resistance should be open circuit.
Measure the resistance across the exposed terminals
of the Gas Valve Operator.
Resistance should be approximately 200 Ohms.
Test 2:
Measure the resistance across one exposed terminal
of the gas valve operator and a suitable earth connection.
Resistance should be open circuit.
Isolate as per TOPs P4
and refit as necessary