Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect the Thermostat 'On/Off function' multiplug
(two Orange/Black wires) from the PCB
Turn thermostat to Max position
(two Orange/Black wires) from the PCB
Turn thermostat to Max position
Measurement:
Test 1:
Turn thermostat to Off position.
Measure the resistance across the two Orange/Black wires on the disconnected multiplug.
Expected resistance open circuit.
Test 2:
Turn thermostat to Max position.
Measure the resistance across the two Orange/Black wires on the disconnected multiplug.
Expected resistance close circuit.
Reconnect plug after the test.
Turn thermostat to Off position.
Measure the resistance across the two Orange/Black wires on the disconnected multiplug.
Expected resistance open circuit.
Test 2:
Turn thermostat to Max position.
Measure the resistance across the two Orange/Black wires on the disconnected multiplug.
Expected resistance close circuit.
Reconnect plug after the test.
Isolate as per TOPs P4
and refit as necessary