Fault Diagnosis - herrmann HG 30 Série Caractéristiques Techniques, Instructions De Montage Et De Service

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5.7 Fault diagnostics
Fault
Fan motor does not start
Fan is running; fault occurs during
pre-purge
Blower is running; fault occurs during
safety time
No ignition spark
Fault on burner cannot be eliminated;
blower runs with maximum speed
Cause
No power detectable
Burner control is defect
Fan is defect
Signal for stage 1 is off
Flame appears during pre-purge
Ionisation electrode is defect
Ionisation current is too low
Cable of the ionisation electrode is defect
Missing protective ground between
control box and burner casing
No flame
Gas-air system defect
Shutoff valve of gas pipe is closed
Ignition unit is defect
Ignition electrodes are defect
Ignition cables are defect
Electrodes positioned incorrectly
Burner control is defect
Fan is defect
Speed control/signal generator is defect
Wiring between speed control/signal generator
and fan is defect
Remedy
- Check wiring
- Replace burner control
- Replace fan
- Check temperature setting at the boiler thermostat
- Check wiring between burner
and boiler control
- Check function of the gas-air system
- Check wiring of the solenoid valves
- Check ionisation electrode (connection to ground)
- Replace electrode bloc with cable
- Check position of the ionisation electrode
- Improve combustion
(increase/decrease gas volume flow)
- Replace electrode bloc with cable
- Check wiring. To provide power supply, the burner
must be connected to phase, neutral and
protective ground.
- Non-ignitable mixture. Check setting of gas-air
system and the fan speed.
- Surface load (burner performance) is too low. Check
setting on gas-air system and check fan speed.
- Replace gas-air system
- Open shutoff valve
- Replace ignition unit
- Replace electrode bloc with cable
- Replace electrode bloc with cable
- Align electrodes according to fig. 10
- Replace burner control
- Replace fan
- Replace speed control/signal generator
- Check wiring, if necessary replace cable