67
Displayed fault
code
System characteristics
Cause
Measures
396
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.
399
Burner in a fault state
IO electrode earth fault,
HBMU heat management
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.
400
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.
401
Burner in a fault state
IO electrode earth fault,
HBMU heat management
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.
402
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.
403
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.
404
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.
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.
Troubleshooting
Fault messages
(cont.)
6173886
Diagnosis