47
A
B
Fig. 28
A
HBMU heat management unit
B
Programming unit
Fault messages
Note
For diagnosis and troubleshooting, see chapter
"Repairs".
Fault messages dependent on appliance equipment
level
Displayed fault
code
System characteristics
Cause
Measures
7
No DHW heating
Lead break, cylinder tem-
perature sensor
■
Check the DHW setting in the
commissioning assistant and cor-
rect if necessary.
■
Check the cylinder temperature
sensor (terminal 2).
■
Measure voltage at sensor input
on HBMU heat management
unit. Set value: 3.3 V
–
with sen-
sor disconnected
Replace faulty component if neces-
sary.
8
No DHW heating
Short circuit, cylinder tem-
perature sensor
Check the cylinder temperature
sensor (terminal 2).
Replace faulty component if neces-
sary.
Troubleshooting
Overview of electronics modules
6174240
Diagnosis