Honeywell Central Heating Cooker Natural Gas - Manual (Page 38)

38
FAULT FINDING
ELECTRICITY SAFETY - Switch off electrical supply to unit before making any electrical tests.
FAULT POSSIBLE CAUSE ACTION
BURNER WILL NOT START Boiler Thermostat or other Ensure all controls are calling for heat
system controls satisfied
Fuse blown Fit new 5 amp fuse, if it blows again check
for short circuit in wiring
No gas/pressure low Ensure all isolation valves are open and
minimum gas pressure on inlet is 17/20
mbar.
Blocked Flue Neon illuminated Press the reset button on lower control
panel. NB Only try twice
Ensure flue is not blocked and minimum
draught of 0.04”WG
Ensure bulb for thermostat is in pocket.
Poor Earth Check earth continuity and all earths connected.
FAN DOES NOT RUN Connections Check connections and plugs 24DC 230V
NO FAN NOISE
Gas Valve solenoid Touch coil with non magnetic screwdriver,
if not magnetic replace gas valve
BURNER IGNITES Live and neutral reversed Check polarity
MOMENTARILY THEN GOES
TO LOCKOUT
Ionisation probe incorrect Adjust gap to that specified
Ionisation probe damaged Replace probe
Ionisation probe lead damaged Repair/replace
Poor earth to unit Check continuity and all earth connections
Control box wiring faulty Check control box wiring and wiring
into molex
Venturi throttle setting excessive Check combustion figures are to spec
BURNER IGNITES AND THEN Low/No gas pressure Check supply pressure
GOES OUT AFTER A FEW
MINUTES
Breakdown in ionisation circuit Check ionisation circuit whilst running is
above 0.9 µa DC
BURNER FAN RUNS Damaged ignition electrode Replace electrode
BUT DOES NOT IGNITE
Ignition lead not connected Reconnect leads/replace
/damaged
Ignition spark excessive Reset spark gap to specified 3mm
Ignition control not seated Ensure control located correctly and pins
on gas valve not bent
Ignition control box faulty Replace