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BURNER STARTING DIFFICULTIES AND THEIR CAUSES
DIFFICULTIES
The burner goes through
the pre-purge period nor-
mally, the flame ignites,
but the burner goes to
lock-out within 2 seconds
after the ignition.
The burner goes to lock-
out, after the pre-purge
period, because the flame
does not ignite.
The burner does not pass
through the pre-purge pe-
riod and the control box
goes to lock-out.
The burner does not start
at the thermostat closing.
The burner continues to
repeat the starting cycle
without going on lock-out.
N.B.: If problems still occur after all of the above checks have been made, check the electrical
connections on the plug and sockets, the damper and burner motor, gas control wiring igni-
tion transformer and external interlocks, if the burner still fails to function, replace the con-
trol box.
OPERATING FAULTS
The burner goes to lock-out because of :
The burner shuts-down if the gas pressure switch opens.
2049
The ionization probe is earthed or not in contact with the flame, or its
wiring to the control box is broken, or there is a fault on its insulation
to earth.
The ionization current is weak (lower than 3 m A).
The gas pressure switch is set too close to its working-pressure.
The valves are passing too little gas (low pressure in the gas pipe-
work).
The valves are defective.
The ignition arc is irregular or not present.
The pipe has not been purged from the air.
On the servomotor (1, fig. 1, page 1) lever N5 and lever ST1 do not
respect the setting sequences (see page 8).
The air pressure switch does not change over: it has failed or the air
pressure is too low (combustion head bad set).
Flame simulation exists (or the flame really lights).
Gas is not supplied.
The gas pressure switch does not close its contact due to incorrect
setting or a faulty switch.
The air pressure switch is changed over to the operational position.
This concerns a very particular irregularity, caused by the fact that
the gas pressure in the gas-mains lies very close to the value to
which the gas pressure switch has been set.
As a result of this, the sudden falling-off of pressure at the opening of
the valves causes the opening of the pressure switch.
However this only temporarily, because the valves immediately close
again, so then does the pressure switch, because the pressure
builds-up again the cycle to be repeated over and over.
This can be remedied by lowering the setting of the pressure switch.
– Flame failure
:
– Ionization probe earthed
:
– Opening of the air pressure switch
10 GB
CAUSES
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