Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Disconnect plug marked JP5
Measurement:
Test 1:
With DHW temperature selector set to maximum,
measure the resistance across the blue wire (connection 4),
and the black wire (connection 5).
Resistance measured should be approximately 11 kOhms.
Turn CH temperature selector to minimum.
Resistance should reduce to less than 100 Ohms.
Test 2:
With DHW temperature selector set at minimum, measure the resistance across the white wire (connection 6), and the black wire (connection 5).
Resistance measured should be approximately 11 kOhms.
Turn DHW temperature selector to maximum.
With DHW temperature selector set to maximum,
measure the resistance across the blue wire (connection 4),
and the black wire (connection 5).
Resistance measured should be approximately 11 kOhms.
Turn CH temperature selector to minimum.
Resistance should reduce to less than 100 Ohms.
Test 2:
With DHW temperature selector set at minimum, measure the resistance across the white wire (connection 6), and the black wire (connection 5).
Resistance measured should be approximately 11 kOhms.
Turn DHW temperature selector to maximum.
Isolate as per TOPs P4
and refit as necessary