Viessmann Vitodens 050-W Installation And Service Instructions Manual page 59

Fault messages
(cont.)
Displayed fault System characteristics
code
62 Burner in a fault state
63 Burner in a fault state
64 Normal operation; burner re-
starts.
67 Burner in a fault state
68 Burner in a fault state
Cause
High limit safety cut-out
has responded.
Flue gas temperature lim-
iter has responded.
Flame loss in the stabilisa-
tion or operating phase.
Ionisation current lies out-
side the permissible range
Flame signal is already
present at burner start.
Troubleshooting
Measures
Check heating system fill level.
■
Check pre-charge pressure in di-
■
aphragm expansion vessel. Ad-
just to required system pressure.
Check whether flow rate is suffi-
■
cient (circulation pump).
Check function of 3-way diverter
■
valve. Vent the system.
Reset the appliance.
Check heating system fill level.
■
Check pre-charge pressure in di-
■
aphragm expansion vessel. Ad-
just to required system pressure.
Check whether flow rate is suffi-
■
cient (circulation pump).
Check function of 3-way diverter
■
valve.
Vent the system.
Reset the appliance once the flue
system has cooled down.
Check gas supply (gas pressure
■
and gas flow switch).
Check balanced flue system for
■
flue gas recirculation.
Check ionisation electrode (re-
■
place if necessary): Check the
distance of the electrode to the
burner gauze assembly and its
contamination level.
Check gas supply (gas pressure
and gas flow switch), check gas
solenoid valve and inlet strainer.
Check ionisation electrode for the
following:
Clearance to burner gauze as-
■
sembly
Check electrode/burner gauze
■
assembly for contamination.
If specified measures do not help,
replace fan unit.
Reset the appliance.
Close the gas shut-off valve. Re-
move connecting cable of the ioni-
sation electrode. Reset the appli-
ance.
If the fault persists, replace the
HBMU heat management unit. See
chapter "Replacing the HBMU heat
management unit".
59