Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Remove both wires from the limit thermostat
Measurement:
Measure the resistance between one of the terminals of the limit thermostat and a suitable earth.
Expect a resistance of greater than 1 Mohm.
(O.L is acceptable because this is greater than 1 Mohm)
Is the resistance measured as expected?
Note:
Image shows the limit thermostat removed for clarity but the test is carried out with the overheat stat in situ attached to the primary heat exchanger.
Expect a resistance of greater than 1 Mohm.
(O.L is acceptable because this is greater than 1 Mohm)
Is the resistance measured as expected?
Note:
Image shows the limit thermostat removed for clarity but the test is carried out with the overheat stat in situ attached to the primary heat exchanger.
Isolate as per TOPs P4
and refit as necessary