Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
CH Demand
Attach temperature clamps to flow and return pipes as shown in the picture
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Tap reset button to skip self check.
Hold the radiator +/- buttons simultaneously
for 5 seconds to set boiler to service mode.
Allow flow temperature to reach approx. 60°C.
Is the temperature differential below 25°C?
Note:
To reduce time taken for this test you
may wish to turn off some radiators.
To exit service mode tap the reset button.