Does fan run after approx. 30 secs.?
Check flue and ignition system
No
Check pitot tube (in fan outlet) and air
hoses are not obstructed and correctly
aligned.
Check or replace air pressure switch.
Does the fan run now?
Is 230 VAC present across fan
terminals?
Replace electronic board
Yes
No
No
Yes
No
Yes
Yes Check/replace fan
Does the boiler
commence ignition
Check air/flue gas system
is correctly fitted and not
obstructed
Yes
No
Replace electronic board
No
Yes Are electrodes sparking at
the burner? Yes Go to sheet E
No
Check electrodes and
electrode leads.
Replace as necessary.
Sheet D
Does yellow fan operation
indicator glow? Does yellow fan
operation indicator flash?
