Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Control Thermostat in the Off position
Measurement:
Disconnect the Purple spaded wire (connection 7) and the Yellow spaded wire (connection 8) from the Control Thermostat and measure the Resistance across connections 7 and 8 on the Thermostat.
Isolate as per TOPs P4
and refit as necessary