Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect plug connector (marked JP11) from PCB
Disconnect the leads from the water pressure switch
Disconnect the leads from the water pressure switch
Measurement:
Test 1:
Test between blue, 1 (from the bottom) on JP11 and blue spade at water pressure switch.
Expect zero resistance
Test 2:
Test between white, 2 (from the bottom) on JP11 and white spade at water pressure switch.
Expect zero resistance
Test between blue, 1 (from the bottom) on JP11 and blue spade at water pressure switch.
Expect zero resistance
Test 2:
Test between white, 2 (from the bottom) on JP11 and white spade at water pressure switch.
Expect zero resistance
 h50011 water pressure switch unplugged.jpg)
Isolate as per TOPs P4
and refit as necessary