32
Display
Measure
Control unit issues a heat
demand
No
Increase set value. Ensure
heat transfer.
Yes
Fan starts
No
Fault 59, 457
Check the fan connecting ca-
bles. Check the fan power
supply.
Yes
Ignition
No
Fault 359
Check ignition module (con-
trol voltage 230 V across
plug "X1/54" terminals "L"
and "N" on the HBMU).
Check the gas supply.
Yes
Gas solenoid valve opens
No
Fault 357
Check the gas supply pres-
sure.
Yes
Ionisation current builds
No
Fault 369, 380
Check distance of ionisation
electrode on burner gauze
assembly.
Purge the gas line.
Yes
Burner in operation
No
Shuts down below the set
boiler water temperature and
restarts immediately.
Check the flue system for
tightness (flue gas recircula-
tion). Check gas flow pres-
sure.
Yes
Automatic calibration of
the combustion controller
No
Fault 62, 373
Ensure adequate heat trans-
fer. Reset the appliance.
Fault 346, 377
Check gap between ionisa-
tion electrode and burner
gauze assembly.
Check flue system. Remove
flue gas recirculation if re-
quired.
Reset the appliance.
Operating instructions
For further details regarding faults, see "Troubleshoot-
ing".
Commissioning, inspection, maintenance
Function sequence and possible faults
6174240