Viessmann VITOCAL 300, Installation And Service Instructions Manual

Page: 124 / 160

This setting defines the temperature
that the external heat source must
reach before the mixer opens. This
temperature is only significant when
the external heat source starts.
During operation, the flow tempera-
ture of the external heat source can
fall below this temperature limit. Access
& " System settings "
& " Program "
& " Ext. heat source "
& "Mixer T limit" (
1
/
!
)
Standard setting 60 °C
Setting range 0 to 80 °C
Minimum runtime
Setting of the period during which the
external heat source can receive a
demand signal. A demand signal for
the external heat source can be can-
celled by the control unit after this per-
iod has expired.
The runtime must not be less than the
specified minimum. Access
& " System settings "
& " Program "
& " Ext. heat source "
& "Min. runtime" (
P
/
Q
)
Standard setting 2:00 h
Setting range 0:00 to
24:00 h
Runtime without demand
The demand signal is cancelled if the
flow temperature in "Runtime without
demand" is above the mixer dead
zone (see pages 110).
Access
&
" System settings "
&
" Program "
&
" Ext. heat source "
&
"Runtime w/o demand" (
P
/
Q
)
Standard setting 2:00 h
Setting range 0:00 to
24:00 h
Mixer active zone/dead zone
For function description see
page 110. Access
&
" System settings "
&
" Program "
Mixer temperature limit
124
Control settings, external heat source
55
92
901
GB