Overview Of Electronics Modules; Fault Messages - Viessmann VITODENS 100-W Installation And Service Instructions Manual

Overview of electronics modules

A
B
Fig. 28
HBMU heat management unit
A
Programming unit
B

Fault messages

Note
For diagnosis and troubleshooting, see chapter
"Repairs".
Fault messages dependent on appliance equipment
level
Displayed fault System characteristics
code
7 No DHW heating
8 No DHW heating
Cause
Lead break, cylinder tem-
perature sensor
Short circuit, cylinder tem-
perature sensor
Troubleshooting
Measures
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.
Check the cylinder temperature
sensor (terminal 2).
Replace faulty component if neces-
sary.
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