Glow-worm Ultimate 50CF - Manual (Page 17)

17 221787B
9 Fault Finding
PILOT WILL NOT LIGHT
START HERE
Check flue blockage safety device
has not operated,
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 multi-functional control knob.
Does gas flow freely?
Rectify blockage in pilot injector,
or renew pilot injector.
Undo tubing nut at pilot outlet
of the multi-functional control.
Press gas valve knob.
Does gas flow freely?
Change blocked pilot tube.
Change multi-functional control.
Does pilot stay alight when
multi-functional control
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 fault finding diagram.
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
Diagram 9.1 BOILER PILOT FAULT-FINDING
5291