Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to DC Volts 
Use Insulation Mat as required
Ensure no hot water demand
Ensure no hot water demand
| WARNING! - Mains voltage is expected during test follow TOPs P4 live testing procedure |
Measurement:
Test 1:
Measure the voltage at the red wire (pin 5) of X22 to a suitable earth
point. This is the supply voltage of approximately 5V DC.
If this voltage is NOT present select that
option below instead of continuing to test 2.
Test 2:
Measure the voltage at the white wire (pin 4)
of X22 to a suitable earth point.
Expect approximately 5V DC at this time.
Open a hot tap and repeat test 2.
There should now be approximately 4.3V DC.
Measure the voltage at the red wire (pin 5) of X22 to a suitable earth
point. This is the supply voltage of approximately 5V DC.
If this voltage is NOT present select that
option below instead of continuing to test 2.
Test 2:
Measure the voltage at the white wire (pin 4)
of X22 to a suitable earth point.
Expect approximately 5V DC at this time.
Open a hot tap and repeat test 2.
There should now be approximately 4.3V DC.
