9 Fault Finding

9.1 Electrical 9.2 Electrical Supply Failure

Important. On completion of the Service/Fault Finding task which has required the breaking and remaking of the electrical connections the earth continuity, polarity, short circuit and resistance to earth checks must be repeated using a suitable multimeter.Refer to neon indicators “An Aid to Fault Finding” diagram 9.1,Boiler Fault Finding diagram 9.2, Pump Overrun Fault Finding diagram 9.3 the Functional Flow diagram 9.4, Gravity Domestic Hot Water and Fully Pumped Central Heating, diagram 9.5, Fully Pumped Open Vented or Sealed Water System, the Pictorial Wiring diagram 9.6, Gravity Domestic Hot Water and Fully Pumped Central Heating and diagram 9.7 Fully Pumped Open Vented or Sealed Water System. Failure of the electrical supply will cause the burner to go out.Operation will normally resume on the restoration of the electricalsupply. If the burner does not relight after an electrical supply failure the overheat device may need resetting.Remove the control cover, see diagram 6.6 and push the resetbutton on the front of the control box, see diagram 6.1.If the cutoff operates at any other time press the reset button andthe burner should relight.If the fault persists refer to fault finding chart.Note, the pump may run for several minutes when power is firstapplied, regardless of a call for heat.

Neon Indicators - An Aid to Fault Finding

THE NEON INDICATORS ARE AN AID TO FAULT FINDING ONLY. FAILURE OF ANY OF THE NEON INDICATORS DOES NOT WARRANT THEREPLACEMENT OF AN OTHERWISE SATISFACTORY PRINTED CIRCUIT BOARD (PCB).
4120

NONO YESYESYESYESYES

Is neon 1 lit? Fault with mains supply or PCB fuse Ignition, pilot or flame proving fault -see detailed fault finding chart.Air flow proving fault - that is fan or airpressure switch - see detailed fault finding chart. Overheat cut off device tripped orthermostat, overheat cut off device faulty - see detailed fault finding chart. Is neon 2 lit?

NONONO

Is neon 4 lit? System satisfactory Is neon 3 lit? Is main burner operating? Multi-functional control/harness problem- see detailed fault finding chart.

NEONINDICATORS Diagram 9.1

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