83
Fault number
on the display
System characteristics
Cause
Measures
F.400
Burner in a fault state
Lead break, ionisation
voltage, signal 1
Check ionisation electrode and
connecting cable.
Reset the appliance.
F.401
Burner in a fault state
Short circuit, ionisation
voltage, signal 2
Check ionisation electrode and
connecting cable.
Reset the appliance.
F.402
Burner in a fault state
Lead break, ionisation
voltage, signal 2
Check ionisation electrode and
connecting cable.
Reset the appliance.
F.403
Burner in a fault state
Short circuit, dynamic ioni-
sation current, signal 1
Check ionisation electrode and
connecting cable.
Reset the appliance.
F.404
Burner in a fault state
Lead break, dynamic ioni-
sation current, signal 1
Check ionisation electrode and
connecting cable.
Reset the appliance.
F.405
Burner in a fault state
Short circuit, dynamic ioni-
sation current, signal 2
Check ionisation electrode and
connecting cable.
Reset the appliance.
F.406
Burner in a fault state
Lead break, dynamic ioni-
sation current, signal 2
Check ionisation electrode and
connecting cable.
Reset the appliance.
F.407
Burner in a fault state
Safety chain
Check heating system fill level.
Check circulation pump.
Vent the system.
Reset the appliance.
F.408
Burner in a fault state
Gas valve monitoring re-
lay 1 has responded.
Reset the appliance.
F.410
Burner in a fault state
Internal error, processor,
BCU burner control unit
Reset the appliance.
F.416
Burner locked out
Flue gas temperature sen-
sor incorrectly positioned
Fit flue gas temperature sensor
correctly. See "Repairs".
F.417
Burner in a fault state
Short circuit, 24 V power
supply
Check connecting cable and sup-
ply voltage to the BCU burner con-
trol unit.
Reset the appliance.
F.418
Burner locked out
Lead break, 24 V supply
voltage
Check connecting cable and sup-
ply voltage to the BCU burner con-
trol unit.
Reset the appliance.
F.425
System in control mode, cal-
culation out of operation
Time synchronisation
failed.
Set the time. If external time is
used, check parameters 1504 and
508.
F.426
Burner in a fault state
Short circuit, external un-
lock signal
Check the connection to the HMU
heat management unit.
Reset the appliance.
F.427
Burner in a fault state
Lead break, external un-
lock signal
Check the connection to the HMU
heat management unit.
Reset the appliance.
F.428
Control mode
Short circuit, air mass
sensor, fan unit
Check connecting cable and plug-
in connector.
F.429
Control mode
Lead break, air mass sen-
sor, fan unit
Check connecting cable and plug-
in connector.
Troubleshooting
Fault messages
(cont.)
6130884
Service
