5244
14
OPERATION TROUBLES 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.
O
Lock-out
Unperfect operation of the flame detecting circuit, because of:
- probe to earth;
- defective internal amplifier.
P
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 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.
Содержание GAS 6 P/M
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