Viessmann Vitodens 050-W Installation And Service Instructions Manual page 72

Troubleshooting
Fault messages
(cont.)
Displayed fault System characteristics
code
468 Burner in a fault state
471 No heat demand
474 Burner in a fault state
527, 528 Burner in a fault state
540 Burner in a fault state
574 Normal operation without
room influence
72
Cause
Ionisation current too high
during calibration
System pressure sensor
not available, lead break
or short circuit
Error in scheduled pro-
gram run monitoring
Incorrect HBMU heat
management unit parame-
ter set
Condensate backup in the
heat cell
Room temperature sen-
sor, heating circuit 1 not
available
Measures
Check gap between ionisation
electrode and burner gauze as-
sembly.
Check whether there is a lot of
dust in the ventilation air (e.g. from
construction work).
Reset the appliance.
Note
Deposits on the electrodes indicate
foreign bodies in the ventilation air.
Check the installation room and
flue system for causes of the de-
posits. For example: Laundry de-
tergents, cleaning agents, toilet-
ries, deposits in the ventilation air
supply (chimney).
If burner gauze assembly and ioni-
sation electrode have been re-
placed, also clean fan unit, gas/air
channel and Venturi extension.
Check system pressure sensor
■
(plug ).
aND
Check lead and plug-in connec-
■
tion.
Check whether the supply volt-
■
age to the sensor is 5 V .
Reset the appliance.
If the fault occurs repeatedly, re-
place the HBMU heat management
unit. See chapter "Replacing the
HBMU heat management unit".
Overwrite (flash) the HBMU heat
management unit with the correct
parameter set.
Check system for condensate
■
backup.
Check the condensate drain and
■
trap.
Replace insulation blocks, elec-
■
trodes and burner gauze assem-
bly if necessary.
Note
To prevent water damage, detach
fan unit before removing the burn-
er.
Reset the appliance.
Check external room temperature
sensor for heating circuit or room
temperature sensor on remote
control unit.
Check setting of parameter 933.6