Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Remove control box cover
Disconnect plug marked CN15
Disconnect plug marked CN15
Measurement:
Test 1:
Set DHW temperature selector to maximum
Measure the resistance across the blue wire (connection 3) and the black wire (connection 2).
Resistance measured should be approximately 10.6 kOhms.
Turn DHW temperature selector to minimum.
Resistance should reduce to under 100 Ohms.
Test 2:
Set DHW temperature selector to minimum
Measure the resistance across the white wire (connection 1) and the black wire (connection 2).
Resistance measured should be approximately 10.6 kOhms.
Turn DHW temperature selector to maximum.
Resistance should reduce to under 100 Ohms.
Set DHW temperature selector to maximum
Measure the resistance across the blue wire (connection 3) and the black wire (connection 2).
Resistance measured should be approximately 10.6 kOhms.
Turn DHW temperature selector to minimum.
Resistance should reduce to under 100 Ohms.
Test 2:
Set DHW temperature selector to minimum
Measure the resistance across the white wire (connection 1) and the black wire (connection 2).
Resistance measured should be approximately 10.6 kOhms.
Turn DHW temperature selector to maximum.
Resistance should reduce to under 100 Ohms.
Isolate as per TOPs P4
and refit as necessary