Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Remove the air intake pipe
The air intake is held by one screw attached to the heat exchanger
Remove the leads from the overheat stat which is located on top of the heat exchanger and remove the sensor by twisting anticlockwise with fingers.
The air intake is held by one screw attached to the heat exchanger
Remove the leads from the overheat stat which is located on top of the heat exchanger and remove the sensor by twisting anticlockwise with fingers.
Measurement:
Measure resistance across the sensor.
Isolate as per TOPs P4
and refit as necessary