Condition
Possible cause
Action
Faulty motor contactor.
Change.
Faulty motor.
Change.
Fault in frequency converter or
soft starter (if equipped).
Check error and reset.
Lack of fan air pressure
Condition
Possible cause
Action
Fan motor starts, but during pre-
purge period lockout occurs.
Faulty differential air pressure
switch setting.
Check setting, adjust if necessary.
Dirty or damaged differential air
pressure switch impulse tubes.
Clean or replace.
Faulty differential air pressure
switch.
Change.
Fan suction blocked.
Clean.
Incorrect motor rotation direction. Reconnect motor.
Leakage test failure
Condition
Possible cause
Action
Leakage test failure
Gas block failure
See section
Gas valve proving
.
Gas inlet pressure to burner too
low
Find out cause and repair.
Faulty pressure switch
Change.
Faulty gas valve
Change.
No electric arc for ignition
Condition
Possible cause
Action
Fan motor starts, control voltage
from burner control to ignition
transformer is switched on, no
electric arc is formed, and after a
short time lockout occurs.
Dirty or damaged ignition
electrodes.
Clean or change.
Ignition electrodes too far apart.
Adjust electrodes according to
instructions in section
Adjusting
combustion head
.
Damaged or disconnected ignition
cable.
Change.
Faulty ignition transformer.
Change.
Flame does not form
Condition
Possible cause
Action
Gas or oil use:
Fan motor starts, the electric arc
used for ignition is in order. After
a short period of time lockout
occurs.
Fuel valves do not open or open
too slowly:
Break in control circuit.
Faulty actuator.
Find out cause of the break.
Replace faulty part.
Faulty fuel pressure.
Check components (filter, throttle
plug, regulator, pressure switch)
and adjust.
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M4263 2206EN
