What To Do; When Rooms Are Too Cold - Viessmann VITODENS Operating Instructions Manual

When rooms are too cold

Cause
Heating system is switched OFF
ON/OFF indicator 8 (green) is OFF
Control unit or remote control unit is in-
correctly adjusted
Only when operating with DHW load-
ing:
DHW priority (wp in the display)
No fuel
Control unit fault: U is displayed and
the red fault indicator flashes
Burner fault: E is displayed and the
red fault indicator on the control unit
flashes
Heating water temperature or required
room temperature too low
Remote control fault
Remedy
Switch ON system ON/OFF switch 8
&
(see page 10)
&
Switch ON mains electrical isolator, if
installed (outside boiler room)
& Check the circuit breaker inside
power distribution (main domestic
fuse) and reset it, if required
Set up "Heating and DHW" G (see
page 12)
Wait until the DHW cylinder has been
heated up or, if an instantaneous water
heater is installed, until no more DHW
is being drawn (p is extinguished in
the display)
Oil/LPG:
Check fuel level and, if necessary, re-
order fuel.
Natural gas:
Open the gas shut-off valve and check
with your gas supplier, if required.
Check the fault code on the display
(see page 21) and notify your local
heating contractor
Press burner fault reset E – if that at-
tempt to start also fails, notify your
heating contractor
Raise the heating water temperature or
the required room temperature (see re-
mote control operating instructions)
Notify your local heating contractor

What to do

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