Fault Messages On The Display - Viessmann Vitodens 100 Installation And Service Instructions Manual

System characteristics
What to do if ...
... the rooms are cold,
even though the burner is
working

Fault messages on the display

(cont.)
Cause
Hot water priority
Fault on Vitotrol 100 or
similar programmable
room thermostat
Any faults in your heating system are
indicated on the display by a flashing
fault symbol "U".
Read the fault code on the display
and report it to your heating engineer.
What needs doing?
Solution
Switch off hot water de-
mand or wait until de-
mand is satisfied.
Contact your heating en-
gineer.
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