Set Appliance State:

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

Measurement:

Measure the temperature differential after the appliance has been running for at least 2 minutes.
Expected differential approximately 20°C or less.
Notes:
To reduce the time for the test the heating load can be reduced
by turning off some radiators.
Differential may be higher at initial system startup.