Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Turn Hot Water Tap On
Remove pump flow microswitch from flow switch head
ON/OFF Switch ON
Summer/Winter button set to Summer
CH Temperature selector to minimum
DHW Temperature selector to maximum
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Observation:

Allow pump to run
Does the pump flow switch spindle fully extend.
Replace microswitch after test.