What To Do; System Characteristics - Viessmann VITODENS 100 Operating Instructions Manual

System characteristics

What to do if ...
... the heating system
doesn't come on
Fuse has triggered
(either at the fuse board
or in the controls)
... the boiler does not
switch on (or switched on
infrequently)
Cause
System switch switched
off
System controls includ-
ing room thermostats
not calling for heatKnob
"tr" is set to "9"
Knob "tr" is set to "9" Set required heating
Contact your heating en-
gineer
No gas
Control fault

What to do

Solution
Switch on
System controls to create
demand. 9
water temperature (see
page 9)
Contact your gas utility
supplier or heating engi-
neer
Read off the fault codes
in the display. Contact
your heating engineer
and report fault codes.
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