105
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
4C
X
Mixer closes
Lead break,
flow tempera-
ture sensor,
heating circuit
3 (with mixer)
Check flow temper-
ature sensor
50
X
X
No DHW heat-
ing
Short circuit,
cylinder tem-
perature sen-
sor
Check sensors
(see page 118)
51
X
X
No DHW heat-
ing
Short circuit,
outlet temper-
ature sensor
Check sensor (see
page 118)
58
X
X
No DHW heat-
ing
Lead break,
cylinder tem-
perature sen-
sor
Check sensors
(see page 118)
59
X
X
No DHW heat-
ing
Lead break,
outlet temper-
ature sensor
Check sensor (see
page 118)
A7
X
Control mode
as per deliv-
ered condition
Programming
unit faulty
Replace program-
ming unit
Troubleshooting
Fault codes
(cont.)
5457 552 GB
Service