Viessmann VITOLIGNO 300-C Installation And Service Instructions Manual page 175

Display and control elements
Function of appliance mains isolator
A
Fig. 105
The appliance ON/OFF switch
cover A .
Note
Do not operate the appliance ON/OFF switch if the
boiler is running.
Pressing the "START/STOP" button can cause burn-
out in the boiler.
Control functions
Heating water buffer cylinder
The heating water buffer cylinder is used to store
excess energy from heat generators.
The buffer charging level is detected by buffer temper-
ature sensors. The control unit uses the buffer charg-
ing level to calculate the combustion output of the
boiler.
Optimum settings of the heating system have a posi-
tive effect on the service life and efficiency of the
boiler.
The set temperature of the heating water buffer cylin-
der depends on the following parameters:
■ "Buffer" heating curve (slope and level)
■ "Buffer" operating mode
■ Outside temperature
(cont.)
The appliance mains isolator is used to isolate the con-
trol unit from the power supply. It does not turn off the
mains power supply.
After switching off, there are still live components
inside the control unit enclosure.
is located behind
Note
■ Matching the heating curve ("Buffer") to the volume
of the heating water buffer cylinder prevents cycling
of the boiler.
■ A boiler runtime of at least 1 hour should be ach-
ieved.
■ Standard values
–
–
Danger
Live components can cause severe injuries.
When carrying out maintenance work, isolate
the entire system from the power supply.
Check that it is no longer live.
Small heating water buffer cylinder
Low level of heating curve indicates early modulat-
ing.
Large heating water buffer cylinder
High level of heating curve indicates late to no
modulating.
Function description
175