Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to Resistance Set meter to measure resistance
Remove plug from top of pump

Measurement:

Test 1:
Measure the resistance between the
L and N connections at the pump.
Resistance should be approximately 160 Ohms.
Test 2:
Measure the resistance between the
L and earth connections at the pump.
Resistance should be greater than 1M Ohm.
Test 3:
Measure the resistance between the
N and earth connections at the pump.
Resistance should be greater than 1M Ohm.