Viessmann VITODENS 100-W Installation And Service Instructions Manual page 28

Troubleshooting
Fault messages on the display
Fault code System characteris-
on display tics
b0 Burner switched off
b8 Burner switched off
E5 Burner switched off
F0 Burner switched off
F1 Burner in a fault
state
F2 Burner in a fault
state
F3 Burner in a fault
state
F4 Burner in a fault
state
28
(cont.)
Cause
Short circuit, flue
gas temperature
sensor
Flue gas tempera-
ture sensor lead
broken
Internal fault
Internal fault
Max. flue gas tem-
perature exceeded
Temperature lim-
iter has responded
Flame signal is
already present at
burner start
No flame signal is
present
Measures
Check sensor (see
page 34).
Check sensor (see
page 34).
Check ionisation elec-
trode and connecting
leads.
Press "Reset" (see
page 30).
Replace control unit.
Check heating system fill
level. Check circulation
pump. Vent system.
Press "Reset" (see
page 30).
Check heating system fill
level. Check circulation
pump. Vent system.
Check temperature limiter
and connecting leads.
Press "Reset" (see
page 30).
Check ionisation elec-
trode and connecting
lead.
Press "Reset" (see
page 30).
Check ignition/ionisation
electrode and connecting
leads, check gas pres-
sure, check gas train, igni-
tion, ignition module and
condensate drain.
Press "Reset" (see
page 30).