Viessmann Vitodens 100-W Installation And Service Instructions Manual page 34

Troubleshooting
Fault messages on the display
Fault code System characteris-
on the dis- tics
play
51 No DHW heating
52 Burner blocked
58 No DHW heating
59 No DHW heating
5A Burner blocked
A9 Regulated operation
without Open Therm
device
b0 Burner blocked
b8 Burner blocked
E5 Burner blocked
F0 Burner blocked.
F1 Burner in a fault
state
34
(cont.)
Cause Measures
Outlet temperature Check the sensor (see
sensor shorted out page 43).
Short circuit, flow Check connections and
sensor lead; replace sensor if
required.
Cylinder tempera- Check the sensor (see
ture sensor lead page 40).
broken
Outlet temperature Check the sensor (see
sensor lead broken page 43).
Break, flow sensor Check connections and
lead; replace sensor if
required.
Communication Check connections and
fault Open Therm lead; replace Open Therm
device device if required.
Short circuit, flue Check the sensor (see
gas temperature page 44).
sensor
Break, flue gas Check the sensor (see
temperature sen- page 44).
sor
Internal fault Check the ionisation elec-
trode and cables.
Press "Reset" (see
page 36).
Internal fault Replace the control unit.
Max. flue gas tem- Check the heating system
perature exceeded fill level. Check the circu-
lation pump. Vent the sys-
tem.
Press "Reset" (see
page 36).