GZ 2 - GZ 4 / 100 - 1450 kW
Installation-Operation-Maintenance
13
Fault diagnosis
Flame monitoring
makes use of the conductivity and rectifier
effect of the flame, by means of an ionisation electrode.
The
flame signal amplifier only
reacts to the
DC component
of the flame signal.
A short circuit between ionisation electrode and earth
causes a fault cutout.
MMI 810.1
mains voltage
UN = AC 230 V
necessary sensor current for reliable
operation
> 5 µA
Fig. 15: Legend measuring circuit
FE Ionisation
electrode
M Multimeter
Fig. 16: Position ionisation electrode GZ 2
Ionisation current in operation:
GZ 2:
15 - 22 µA
Fault diagnosis MMI 810
Fault
Remedy
Burner does not start,
program display re-
mains the same
•
Faulty electric lead
•
Thermostat or gas switch
"OFF""
Burner does not start,
program display turns
constantly
•
Air pressure switch not in idle
position (working contact must
be open)
•
Connection terminal 1
–
terminal
9 interrupted
•
Operating voltage < 180V
Automatic unit shows a
fault just after starting
pre-venting (line in
blue box)
•
Air pressure switch contact does
not close
•
No load at terminal 5
•
Flame signal
Automatic unit shows a
fault during pre-
venting (blue area)
•
Air pressure switch contact
opens
•
Flame signal
Automatic unit shows a
fault during the safety
period (yellow area)
•
No flame formed (faulty ignition,
valve does not open, etc.)
•
No or weak flame signal (flame
does not hold, poor insulation of
flame sensor, burner not cor-
rectly connected to earth con-
ductor)
Automatic unit shows a
fault during operation
setting (red or green
area)
•
Flame breaks off
•
Air pressure switch contact
opens
•
Flame signal too weak