Fault" Is Displayed - Viessmann VITODENS Operating Instructions Manual

What to do if...
The DHW is too hot
Cause
The control unit is set incorrectly.
The DHW is being heated by the solar thermal system.

"Fault" is displayed

Cause
Heating system fault
and "Service" are displayed
ë
Cause
The service time, as specified by your heating contrac-
tor, has arrived.
"Operation disabled" is displayed
Cause
The controls have been locked.
"External hook-up" is displayed
Cause
The operating program set at the control unit has been
switched over by an external device, e.g. EA1 exten-
sion.
"External program" is displayed
Cause
The operating program set at the control unit has been
switched over by the Vitocom communication interface.
"Check filter" is displayed
Cause
The filters in your ventilation unit and in your exhaust
■
air valves are severely contaminated.
The last filter change was more than 1 year ago.
■
50
Remedy
Check and correct the DHW temperature if required
(see page 35).
Check the settings at the solar control unit and correct
them if required.
Separate operating instructions
Remedy
Proceed as described on page 45.
Remedy
Proceed as described on page 45.
Remedy
Unlock them (see page 41).
Remedy
No action required. Once the external changeover no
longer applies, the set operating program becomes ac-
tive again.
Remedy
You can change the operating program.
Remedy
Change the filters (see page 53).