Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Remove control box cover if necessary
Run hot water tap at flow rate of 3 l/min
Run hot water tap at flow rate of 3 l/min
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Measure the DC voltage between the Red wire on connector X22 (4th connection up from the bottom) and a suitable earth, with the connector X22 attached to the PCB.
Expect a steady voltage of approximately 2.4 vdc.
Is the voltage measured as expected?
Expect a steady voltage of approximately 2.4 vdc.
Is the voltage measured as expected?
Isolate as per TOPs P4
and refit as necessary