69
Displayed fault
code
System characteristics
Cause
Measures
405
Burner in a fault state
Ionisation electrode earth
fault, HBMU heat man-
agement unit faulty
Check IO electrode for earth fault.
If the fault persists, replace the
HBMU heat management unit. See
chapter "Replacing the HBMU heat
management unit".
Reset the appliance.
406, 408, 410
Burner in a fault state
HBMU heat management
unit faulty
Replace the HBMU heat manage-
ment unit. See chapter "Replacing
the HBMU heat management unit".
Reset the appliance.
416
Burner locked out
Flue gas temperature sen-
sor incorrectly positioned
Fit flue gas temperature sensor
correctly. See "Repairs".
Carry out mains reset after fault
has been remedied.
417, 418
Burner in a fault state
HBMU heat management
unit faulty
Replace the HBMU heat manage-
ment unit. See chapter "Replacing
the HBMU heat management unit".
Reset the appliance.
425
System operating normally;
calculation not working
Calculation values can be
viewed via software tool.
Time synchronisation
failed
Set the time.
446
Burner in a fault state
Deviation, heat generator
flow temperature sensor/
high limit safety cut-out
Check the flow temperature sen-
sor/high limit safety cut-out.
Check plug-in connection and lead
to sensor.
Reset the appliance.
447, 448
Burner in a fault state
Deviation, ionisation volt-
age/ionisation current sig-
nal
Replace the HBMU heat manage-
ment unit. See chapter "Replacing
the HBMU heat management unit".
Reset the appliance.
449, 450, 451,
452
Burner in a fault state
Error in scheduled pro-
gram run monitoring
Reset the appliance. If the fault oc-
curs repeatedly, replace the HBMU
heat management unit. See chap-
ter "Replacing the HBMU heat
management unit".
453
Burner in a fault state
Synchronisation error, se-
quence
Reset the appliance. If the fault oc-
curs repeatedly, replace the HBMU
heat management unit. See chap-
ter "Replacing the HBMU heat
management unit".
454
Burner in a fault state
Incorrect HBMU heat
management unit parame-
ter set
Flash correct HBMU heat manage-
ment unit parameter set.
455, 456
Burner in a fault state
Error in program run moni-
toring
Reset the appliance. If the fault oc-
curs repeatedly, replace the HBMU
heat management unit. See chap-
ter "Replacing the HBMU heat
management unit".
457
Burner in a fault state
Fan sluggish or blocked.
Reset the appliance.
Check fan for sluggishness. In the
case of severe contamination or
grinding noises, replace fan unit.
Troubleshooting
Fault messages
(cont.)
6179762
Diagnosis