Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Remove the leads from the Modulator
Measurement:
Measure the resistance across the terminals of the gas valve modulating coil.
Resistances should be approximately as in the table below.
Resistances should be approximately as in the table below.
| Pins | Resistance in Ohms |
| Modureg | 80 |
Isolate as per TOPs P4
and refit as necessary