Supplied By www.heating spares.co Tel. 0161 620 6677
44
220692C
44
SECTION
Fault Finding
11
Before detailed checking of electrical components ensure that remote controls are calling for heat. Check the gas supply is free of obstructions and
purged of air. Check the overheat cutoff has not operated. Isolate the electrical supply and physically check ALL cables, connections and the printed
circuit board fuse. Check the air tubes to the air pressure switch. Switch on the electrical supply and check for correct polarity.
Turn the boiler thermostat to its maximum setting. Also check fuses.
Is there 240V~ between 12 and
10 and between 11 and 10 ?
Is there 240V~ between yellow connection
on overheat device and 10 ?
Is there 240V~
between 6 on thermostat and 10 ?
Is there 240V~ between
1 on air pressure switch and 10 ?
Is there 240V~ between 3 on air
pressure switch and 10 ?
Does fan run?
Does fan Hunt?
Replace printed circuit board.
Check lead continuity and inspect electrode
and lead for damage.
Check for pilot jet blockage,
incorrect electrode adjustment.
If satisfactory replace gas valve.
Isolate supply, test harness and replace
as required.
Inspect electrode lead / connection
for poor contact. Check electrical supply
polarity and correct if necessary.
If satisfactory replace printed circuit board
Isolate supply, test harness continuity.
If satisfactory replace printed circuit board.
Correct power supply problem.
Check overheat reset.
If satisfactory replace overheat device.
Replace thermostat.
Check yellow cable between printed circuit
board and air pressure switch.
If satisfactory replace printed circuit board.
Replace air pressure switch.
Is there 240V~ between motor connections
on fan?
Isolate electrical supply test fan harness
continuity.
If satisfactory replace printed circuit board.
Inspect air tubes for leaks, kinks and
correct fitting. If satisfactory replace faulty
air pressure switch.
Is there a spark at pilot burner?
Does pilot light?
With pilot lit does spark stop?
Replace gas valve.
System satisfactory.
Does main burner light?
Is neon 4 lit?
Is neon 3 lit?
Replace fan.
Is neon 2 lit?
Is neon 1 lit?
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
Is there 240V~ between 2 on air
pressure switch and 10 ?
Is there 240V~ between pilot gas valve
solenoid blue and brown connections?
Is there 240V~ between main gas
valve solenoid black and blue cables?
AIR PRESSURE SWITCH
MAIN TERMINAL STRIP
CONTROL THERMOSTAT
4780
