Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Gain access to the Control PCB
(the Main PCB will need to be removed)
(the Main PCB will need to be removed)
Measurement:
Ensure that when the user control on the front of the boiler is rotated that the spindle turns the potentiometer on the PCB.
Measure the resistance of the potentiometer and compare to the table below:
Measure the resistance of the potentiometer and compare to the table below:
| Test 1 | Test 2 | RESET - 2.5Kohm | RESET - 8ohm |
| CH+DHW - 3.4Kohm | CH+DHW - 2.5Kohm |
| DHW - 3.2Kohm | DHW - 3.2Kohm |
| OFF - 2.6Kohm | OFF - 3.4Kohm |
Isolate as per TOPs P4
and refit as necessary