Viessmann VITOLADENS333-F, Service Instructions Manual

Page: 88 / 112

External blocking
The "External blocking" function is
connected via external extension
input "
aVD ".
In coding address "32" you can select
the influence the "Ext. blocking" sig-
nal should have on the connected cir-
culation pumps.
External demand
The "External demand" function is
connected via external extension
input "
aVD ".
In coding address "34" you can select
the influence the "Ext. demand" signal
should have on the connected circula-
tion pumps.
The minimum set boiler water tem-
perature in case of external demand
is selected in coding address "9b".
Venting program
During the venting program, the circu-
lation pump will be alternately
switched ON and OFF for 30 s respec-
tively over a period of 20 min.
For a certain period, the diverter valve
is alternately set towards heating and
DHW heating. The burner is switched
OFF during the venting program. The venting program is activated via
code "2F:1". The program is automati-
cally disabled after 20 min, and cod-
ing address "2F" is set to "0".
Fill program
In the delivered condition, the diverter
valve is set to its central position,
enabling the system to be filled com-
pletely. After switching ON the control
unit, the diverter valve no longer goes
into its central position. Afterwards, the diverter valve can be
moved via code "2F:2" into the central
position. In this position, the control
unit can be switched OFF, and the
system can be filled completely.
Control functions
(cont.)
88
Function description
5692
779
GB