121
Dis-
played
fault
code
Const.
Weath.-
comp.
System char-
acteristics
Cause
Measures
48
X
Mixer closes
Lead break,
flow tempera-
ture sensor,
heating circuit
2 (with mixer)
Check flow temper-
ature sensor (see
page 142).
4C
X
Mixer closes
Lead break,
flow tempera-
ture sensor,
heating circuit
3 (with mixer)
Check flow temper-
ature sensor (see
page 142).
50
X
X
No DHW heat-
ing by the boil-
er
Short circuit,
cylinder tem-
perature sen-
sor
Check the cylinder
temperature sen-
sor (see
page 136).
58
X
X
No DHW heat-
ing
No DHW
heating by the
boiler
Check the cylinder
temperature sen-
sor (see
page 136).
90
X
X
Control mode
Short circuit,
temperature
sensor
/
Check sensor
/
on solar control
module.
91
X
X
Control mode
Short circuit,
temperature
sensor
aÖ
Check sensor
aÖ
on solar control
module.
92
X
X
No solar DHW
heating
Short circuit,
collector tem-
perature sen-
sor
Check temperature
sensor
&
on solar
control module or
sensor on the
Vitosolic.
93
X
X
Control mode
Short circuit,
cylinder tem-
perature sen-
sor
Check temperature
sensor at connec-
tion S3 to the
Vitosolic.
94
X
X
No solar DHW
heating
Short circuit,
cylinder tem-
perature sen-
sor
Check temperature
sensor
%
on solar
control module or
sensor on the
Vitosolic.
Troubleshooting
Fault codes
(cont.)
5623 520 GB
Service