Viessmann B1HF - Page 77

77
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.)
6167586
Diagnosis