Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to AC Volts 
CH Demand
Gain access to interface PCB
Remove connector CN7 from the interface PCB and make safe.
NO demands
Remove connector CN7 from the interface PCB and make safe.
NO demands
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
Wait until the fan has stopped after start up sequence.
Test 1: Measure the AC voltage between the top left hand Pin of connector CN7 and a suitable earth. Expect approximately 1.1 VAC
Test 2: Apply a central heating demand.
Measure the AC voltage between the top left hand Pin of connector CN7 and a suitable earth. Expect an increase in voltage of approximately 0.05 VAC or greater from the first voltage measured.
Note: It does not matter if the appliance is displaying a fault code for this test.
Test 1: Measure the AC voltage between the top left hand Pin of connector CN7 and a suitable earth. Expect approximately 1.1 VAC
Test 2: Apply a central heating demand.
Measure the AC voltage between the top left hand Pin of connector CN7 and a suitable earth. Expect an increase in voltage of approximately 0.05 VAC or greater from the first voltage measured.
Note: It does not matter if the appliance is displaying a fault code for this test.
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Isolate as per TOPs P4
and refit as necessary