Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
CH Demand
Attach temperature clamp to flow pipe
Set boiler temperature control to maximum
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Allow appliance to fire and system to heat.
Note.
To speed up the process reduce the heating circuit by turning some rads off.
Observe both temperature reading and boiler operation.
Choose from the following observations.
BOILER SHUTS DOWN AT APPROX. 85°C

BOILER GOES TO OVERHEAT BELOW 85°C
BOILER TEMPERATURE GREATER THAN 90°C AND BOILER STILL FIRED