Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Disconnect air pressure pipes from APS
Measurement:
Measure the resistance between common and normally closed terminals on the APS (terminals 1 and 2)
Expect continuity/zero resistance.
Is the resistance as expected?
Expect continuity/zero resistance.
Is the resistance as expected?

Isolate as per TOPs P4
and refit as necessary