Viessmann VITODENS 100-W Installation And Service Instructions Manual page 49

Fault messages
(cont.)
Displayed fault System characteristics
code
63 Burner in a fault state
67 Burner in a fault state
68 Burner in a fault state
69 Burner in a fault state
70 Burner in a fault state
Cause
Flue gas temperature lim-
iter has responded.
Ionisation current lies out-
side the permissible range
Flame signal is already
present at burner start.
Ionisation current lies out-
side the permissible range
HBMU heat management
unit internal fault
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 once the flue
system has cooled down.
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 the electrode/burner
■
gauze assembly for dirt.
If specified measures don't 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".
Check ionisation electrode for the
following:
Check whether insulation block is
■
touching electrode ceramic.
To check the gas solenoid valve:
■
In the service menu under "b.6",
set the burner output to the lower
heating output for approx. 4 min.
If the fault occurs, replace the
HBMU heat management unit.
See chapter "Replacing the
HBMU heat management unit".
In the service menu under "b.6",
■
switch the burner output from the
lower to the upper heating out-
put. If this fault occurs during
modulation, check the inlet
strainer for dirt. Replace the fan
unit if necessary.
Replace the HBMU heat manage-
ment unit. See chapter "Replacing
the HBMU heat management unit".
49