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Viessmann 5443202
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SCU124
Time period - switch-on conditions
tDTO:
Time period -
switch-on conditions
Adjustment range: 1 ... 100 s
in steps of 1 s
Factory setting: 60 s
The parameter tDTO is used for adjusting the time period
during which the switch-on condition DT O must be per-
manentely fulfilled.
Filling time
tFLL:
Filling time
Adjustment range:
1.0 ... 30.0 min
in steps of 0.5 min
Factory setting: 5.0 min
The filling time can be adjusted using the parameter tFLL.
During this period, the pump runs at 100 % speed.
Stabilization
tSTB:
Stabilization
Adjustment range:
1.0 ... 15.0 min
in steps of 0.5 min
Factory setting: 2.0 min
The parameter tSTB is used for adjusting the time period
during which the switch-off condition DT F will be ignored
after the filling time has ended.
Booster function option
OBST:
Booster function
Adjustment range: ON / OFF
Factory setting: OFF
This function is used for switching on a second pump when
filling the solar system. When solar loading starts, R2 is ener-
gized in parallel to R1. After the filling time (tFLL) has ended,
R2 is switched off.
Note:
The booster function is available in system layout 1
(Arr = 1) only.
The booster function will only be available if the
drainback option has been activated.
Drainback option
A drainback system permits the heat transfer fluid to drain
back into the holding tank when solar energy is not coll-
ected. The drainback option will initiate the filling of the
system when solar loading begins.
If the drainback option ODB is activated, the pump will
operate at 100 % speed for the adjusted filling time tFLL
in order to fill the system with fluid from the holding tank.
After tFLL, pump speed will go down to the adjusted
minimum pump speed nMn. The switch-off conditions will
then be ignored for the stabilization time tSTB in order to
avoid the system from shutting down prematurely.
If the function is activated, the menu items described in the
following (tDTO, tFLL and tSTB) have to be adjusted:
Note:
The drainback option is only available in system
layouts 1 and 2.
ODB:
Drainback option
Adjustment range: OFF / ON
Factory setting: OFF
Note:
A drainback system layout requires additional
components such as a holding tank. The drainback
option should only be activated if all components
required are properly installed.
Note:
When the drainback option ODB is activated, the
cooling functions OCC, OSYC and OSTC as well
as the antifreeze function OCF are not available.
If OCC, OSYC, OSTC or OCF have already
been activated before, they will be deactivated
again as soon as ODB is activated. They will remain
deactivated, even if ODB is deactivated later on.
Note:
When the drainback option ODB is activated,
the temperature differences DT O, DT F and
DT S are set to a fixed adjustment. Additionally,
the adjustment range and the factory setting of
the collector emergency shutdown temperature
EM changes (see the corresponding channel
descriptions for further information).
Previous adjustments made in these channels will
be overridden and have to be entered again if
ODB is deactivated later on.
Note:
Viessmann Vitosol collectors cannot be used in
drainback systems.