Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Turn Hot Water Tap On
ON/OFF Switch ON
Summer/Winter button set to Summer
CH Temperature selector to minimum
DHW Temperature selector to maximum
Electrically disconnect pump flow microswitch at its inline connector
Summer/Winter button set to Summer
CH Temperature selector to minimum
DHW Temperature selector to maximum
Electrically disconnect pump flow microswitch at its inline connector
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Allow pump to run.
Measure resistance across the black and white wire at the inline connector (end that runs to the microswitch).
Resistance should be closed circuit.
Repeat test.
Resistance should be open circuit.
Replace microswitch after test.
Measure resistance across the black and white wire at the inline connector (end that runs to the microswitch).
Resistance should be closed circuit.
| Isolate Mains Power to appliance as per TOP's P4 |
Repeat test.
Resistance should be open circuit.
Replace microswitch after test.
Isolate as per TOPs P4
and refit as necessary