Set Appliance State:
| Isolate Mains Power to appliance as per TOPs P4 |
Set Multimeter to Resistance 
Gain access to PCB (use Insulation Mat as required)
Disconnect connector X13 from the PCB
Disconnect plug from heat exchanger fuse
(and additional sensor if fitted) and pull outwards
as shown in the picture to improve access
Disconnect connector X13 from the PCB
Disconnect plug from heat exchanger fuse
(and additional sensor if fitted) and pull outwards
as shown in the picture to improve access
Measurement:
Check for continuity (zero resistance) on both of the wires running from pins 6 & 8 at connector X13 to their corresponding wire at the disconnected harness at the top of the boiler
Inspect harness and the plugs for good overall condition.
Inspect harness and the plugs for good overall condition.
Isolate as per TOPs P4
and refit as necessary