Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4

Observation:

Measure the temperature of the appliance by measuring at the return pipe by the frost thermostat.
Note:
This appliance incorporates built in frost protection, if the appliance temperature drops below 10 degrees it will fire to prevent freezing until a temperature of 16°C is reached. If the appliance is above 10 degrees but you suspect it has been exposed to temperatures of 10 degrees or below then choose the second outcome below.