34
BURNER FAULT-FINDING (cont.)
ELECTRICAL SAFETY - before making any electrical checks, switch off the mains supply to the boiler
FAULT
MORNING START LOCKOUT
DELAYED IGNITION (BURNER
PULSATES ON STARTUP)
BURNER STARTS VIOLENTLY
BURNER REPEATEDLY
ATTEMPTS TO FIRE
(balanced flue only)
COMBUSTION FUMES SMELL
POSSIBLE CAUSE
Faulty non-return valve or air leak
in two-pipe system
Low voltage to appliance
Combustion settings incorrect
Oil level in tank falling below
burner
Nozzle partially blocked
Low oil pressure
Flue blocked or damaged
Fan slipping on shaft
Pump coupling loose or worn
Delayed ignition
Exhaust gas in combustion air
Baffle access cover not secure
Baffle access cover seal damaged
Burner incorrectly fitted, or fixing
gasket damaged
Flue gasket damaged
ACTION
Replace non-return valve, cure leak
Check with local electricity board
Check combustion under normal running
conditions, check against settings shown in
burner leaflet
Raise tank or fir two-pipe system
Replace nozzle with one of same
specification (see burner leaflet)
Check pump pressure and adjust to settings
shown in burner leaflet
Check flue and rectify/replace as necessary
Check fan and retighten/replace as
necessary
Check fan and rectify/replace as necessary
Reset electrode gap and position to settings
shown in burner leaflet
Check electrodes for damage, replace as
necessary
Check condition of HT leads, replace as
necessary
Remove air hose from boiler end of flue,
leaving burner end in place. If burner starts
normally, check flue for breakdown of seals
and repair/replace as necessary
If indeterminate, leaving hose attached,
pierce a small hole in air hose and use flue
gas analyser to check for carbon dioxide. If
more than trace elements present, check
flue for breakdown of seals and
repair/replace as necessary
Tighten wing nuts, securing door in position
Replace seal as necessary
Check burner fixing gasket, replace as
necessary. Tighten burner mounting nuts
Check gasket, replace as necessary.
Tighten flue mounting nuts