Steca TR A502 TT, Инструкция по установке и эксплуатации

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10.3.1 Drainback
Notice
Danger of malfunction in drainback systems
• In drainback systems, the drainback function must be activated.
• In drainback systems with speed-controlled solar circuit pumps (sys-
tems 1.1 to 4.2), note the following:
– Activation of the drainback function switches off the speed
control of the solar circuit pump, but this can be subsequently
switched on again if desired (
P:18
/
P:19
in Section 11).
– Adjust the minimum speed high enough so that the heat trans-
fer fluid is reliably pumped into the collector.
The following drainback function characteristics can be set:
Filling time: When switched on, the solar circuit pump runs for the
duration of the filling time in order to pump the heat transfer fluid into
the collector.
Stabilising time: After the filling time has expired, the solar circuit
pump continues to run for the duration of the stabilising time. The fol-
lowing applies:
• The solar circuit pump also continues to run for this time even when the
switch-off conditions are satisfied.
• When the speed control is activated and the solar irradiation is too
low (no sun symbol on the display) the pump runs at minimum
speed.
• After expiry of the stabilising time, the controller checks to see if the
solar irradiation is sufficient to continue loading the storage tanks.
Draining time: The solar circuit pump is switched off during the drain-
ing time. This allows the heat transfer fluid to flow back into the drain-
back tank and the solar circuit is automatically drained.
Short startup time: After the draining time has expired, the solar circuit
pump runs for the duration of the short startup time (a few seconds). In
most cases, this supports the draining process and sucks the remaining
heat transfer fluid out of the solar circuit.
Booster pump: The booster pump supports the solar circuit pump dur-
ing the filling time and short startup time. The booster pump can only
be connected when a free output is available.
Notes
• The drainback function cannot be active simultaneously with the
following functions:
– Interval
– Reduction of stagnation phases
– Holiday – recooling
– Active cooling
– Freeze recirculation
• The drainback function can only be activated in systems with a
single solar circuit.