Viessmann Vitodens 222-F B2TA Installation And Service Instructions Manual page 124

Troubleshooting
Fault codes
(cont.)
Dis- Const.
played
fault
code
50 X
51 X
58 X
59 X
A7
A8
A9
124
Weath.- System char-
comp. acteristics
X No DHW heat-
ing
X No DHW heat-
ing
X No DHW heat-
ing
X No DHW heat-
ing
X Control mode
as per deliv-
ered condition
X Burner blocked
The venting
program is star-
ted automati-
cally (see
page 77)
X If a heating cir-
cuit with mixer
is connected,
the burner op-
erates at its
lower heating
output.
If only one
heating circuit
without mixer is
connected, the
burner is
blocked
Cause Measures
Short circuit, Check the cylinder
cylinder tem- temperature sen-
perature sen- sor (see
sor page 140)
Short circuit, Check the outlet
outlet temper- temperature sen-
ature sensor sor (see
page 142)
Lead break, Check the cylinder
cylinder tem- temperature sen-
perature sen- sor (see
sor page 140)
Lead break, Check the outlet
outlet temper- temperature sen-
ature sensor sor (see
page 142)
Programming Replace program-
unit faulty ming unit
Air lock in the Vent the system if
internal circu- the fault message
lation pump continues to be dis-
or minimum played
flow rate not
achieved
Internal circu- Check the circula-
lation pump tion pump
blocked