Viessmann VITODENS 111-W Installation And Service Instructions Manual page 72

Troubleshooting
Fault messages
(cont.)
Displayed fault System characteristics
code
63 Burner in a fault state
64 Normal operation; burner re-
starts.
65 Burner in a fault state
67 Burner in a fault state
72
Cause
Flue gas temperature lim-
iter has responded.
Flame loss during stabili-
sation or operating phase
Flame signal not present
or insufficient at burner
start
Ionisation current lies out-
side the permissible range
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 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 elec-
■
trode to the burner gauze assem-
bly and its contamination level.
Check gas supply (gas pressure
■
and gas flow switch).
Check gas solenoid valve.
■
Check the system for conden-
■
sate backup; check the conden-
sate drain.
Note
Prevent water damage.
■
Detach fan unit before removing
the burner.
Check ionisation electrode and
connecting cable. Check the igni-
tion. Connecting cables to ignition
module and ignition electrode. Igni-
tion electrode for distance and con-
tamination: See also chapter
"Checking and adjusting the igni-
tion and ionisation electrodes".
Check ignition electrode for broken
insulation.
Reset the appliance.
Check gas supply (gas pressure
and gas flow switch), check gas
solenoid valve and inlet strainer.
Check ionisation electrode for the
following:
Distance to burner gauze assem-
■
bly.
Check electrode/burner gauze
■
assembly for contamination.
If specified measures don't help,
replace fan unit.
Reset the appliance.