Glow-worm 56-2 Back Boiler - Manual (Page 22)

22 221781A
10 Fault Finding
Diagram 10.5
BACK BOILER PILOT FAULT FINDING CHART
PILOT WILL NOT LIGHT
START HERE
Check gas line-open all cocks,
rectify any blockages, purge out
any air. Does pilot light?
Apply match to pilot burner instead
of pressing piezo unit button.
Does pilot light?
Undo tubing nut at pilot burner.
Press gas valve knob.
Does gas flow freely?
Replace faulty flue blockage
safety device.
Undo tubing nut at pilot outlet
of gas valve. Press gas valve knob.
Does gas flow freely?
Change blocked pilot tube.
Change gas valve.
Does pilot stay alight when
gas valve knob is released?
PILOT SATISFACTORY
Does pilot flame envelop
thermocouple?
Replace faulty flue blockage
safety device.
Check thermocouple circuit using
Thermocouple fault finding,
see diagram 10.3.
On pressing piezo unit button is
there a spark across electrode
gap?
Pull ignition lead off electrode.
Hold end of lead close to pilot
burner and operate piezo unit.
Is there a spark across gap?
Pull ignition lead off piezo unit.
Using blade of a screwdriver, touch
unit chassis and leave approx.
4mm gap from connection tag on
piezo unit. Operate piezo.
Is there a spark across gap?
Change
piezo unit. Change
ignition lead.
Replace faulty flue blockage
safety device.
NO YES NO YES
NO YES
NO YES
NO YES
NO YES
NO YES
NO YES
NO YES
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