2915246
14
GB
BURNER STARTING DIFFICULTIES AND THEIR CAUSES
The symbol, visible on the reading disc of the pointer, shows the kind of problem.
◆
The control box does not start at the thermostats closing, because of:
- lack of gas;
- the gas pressure switch does not close the contact: bad set;
- the air pressure switch changed over in operation position;
- the control box fuse is broken;
- the servomotor does not totally change over the closing circuit in being between the terminals 11 and 8 of the
control box.
▲
Stop at the start-up, because of:
- the servomotor does not change over the max. opening circuit in being between the terminals 9 and 8 of the
control box.
P Lock-out
The air pressure switch does not change over, because of:
- defective contact;
- insufficient pressure of the air.
■
Lock-out
Unperfect operation of the flame detecting circuit, because of:
- probe to earth;
- defective internal amplifier.
▼
Stop during pre-purge phase, because of:
The servomotor does not change over the minimal opening circuit in being between the terminals 10 and 8 of the
control box.
1 Lock-out due to flame signal lack; if:
- the ionisation probe is not inside of the flame;
- the probe connection to the control box is disconnected;
- the ionization current is insufficient (min. 6 µA).
❚
Lock-out during operation due to:
- flame signal lack;
- no air pressure.
NOTICE
- If lock-out occurs between the start-up and the pre-ignition phase without that a symbol comes out, the cause is
the flame simulation.
- If the burner repeats continuously the start-up cycle without lock-out occurring, this is due to the “oscillation” of
the gas pressure switch caused by a setting very near to the gas network pressure, therefore the pressure
decreasing at the burner start-up is sufficient to actuate the gas pressure switch causing a new start-up.
