Supplied By www.heating spares.co Tel. 0161 620 6677
23
221764B
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.
Turn gas valve knob to Pilot/Ign.
Press gas valve knob.
Does gas flow freely?
Rectify blockage in pilot injector,
or renew pilot injector.
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?
Check aeration. If necessary - Clean
pilot, rectify blockage in pilot
injector, or replace.
Check thermocouple circuit using
Thermocouple and Boiler Overheat
Cut-Off fault finding.
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.
Check electrode gap. Reposition,
or replace electrode as necessary.
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
10 Fault Finding - Pilot
Diagram 10.5
BOILER PILOT FAULT FINDING
0905