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Drainback option
a drainback system permits the heat transfer fluid to
drain back into the holding tank when solar energy
is not collected.the drainback option will initiate the
filling of the system when solar loading begins.
Note:
a drainback system requires additional
components such as a holding tank. the
drainback option should only be activated
if all components required are properly in-
stalled.
the parameter
Filling time
is used to adjust the
time period for which the pump will be run at 100 %
speed in order to fill the system.
the parameter
Stabilisation
is used for adjusting
the time period during which the switch-off condi-
tion will be ignored after the filling time has ended.
the parameter
Initialis.
is used for adjusting the
time period during which the switch-on condition
must be permanentely fulfilled for the filling proce-
dure to start.
the
Booster
option is used for switching on a se-
cond pump when filling the solar system. the corre-
sponding relay is switched on at 100 % speed for the
duration of the filling time.
a short time (Delay time) after the system has been
emptied, the
Drain impulse
option will switch on
the solar pump for an adjustable
Duration
. thus, a
hydrostatic head will form in the flow pipe. When it
falls back into the holding tank, water pockets re-
maining in the collector will be sucked down into
the holding tank.
adjustment channel Description
adjustment range / selection Factory setting
Filling time
Filling time
1 ... 30 min
5 min
stab. time
stabilisation time
1.0 ... 15.0 min
2,0 min
Initialis.
Initialisation time
1 ... 100 s
60 s
Booster
Booster option
Yes, no
no
relay
Booster pump relay selection
system dependent
system dependent
Drain impulse
Drain impulse option
Yes, no
no
Delay
Delay time
1 ... 30 min
3 min
Duration
Drain impulse loading duration 1 ... 60 s
10 s
Funct.
activation / Deactivation
activ., Deactivated
Deactivated
Solar / Opt. functions / Add new function... / Drainback
S1
S3
S2
S4/TR
R1
R2
booster pump
Exemplary drainback system layout
(R2 = booster pump)
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