27
Special functions
With speed control the
LTDC makes it possible to vary the speed of connected pumps.
6.3. - Speed control R1 / R2
6.3.1. - Modes
The following speed modes are available here:
Off:
There is no speed control. The connected pump is only switched on or off with full speed.
Mode M1:
After the purging time the controller switches to the set max. speed. If the temperature
difference ∆T between the reference sensors (collector and storage tank) is less than the set value, then
the speed is decreased by one stage after the control time elapses. If the temperature difference between
the reference sensors is greater than the set value, then the speed is increased by one stage after the
control time elapses. If the controller has adjusted the speed of the pump down to the smallest stage and
the ∆T between the reference sensors is ∆T off, the pump is switched off.
Mode M2:
After the purging time the controller switches to the set min. speed. If the temperature
difference ∆T between the reference sensors (collector and storage tank) is greater than the set value,
then the speed is increased by one stage after the control time elapses. If the temperature difference ∆T
between the reference sensors is below the set value, then the speed is decreased by one stage after the
control time elapses. If the controller has adjusted the speed of the pump down to the smallest stage and
the ∆T between the reference sensors is T∆off, the pump is switched off.
Mode M3:
After the purging time the controller switches to the set min. speed. If the temperature at the
reference sensor (collector) is greater than the setpoint to be set subsequently, then the speed is increased
by one stage after the control time expires. If the temperature at the reference sensor (collector) is less
than the setpoint to be set subsequently, then the speed is decreased by one stage after the control time
expires.
Mode M4:
When the primary storage is loaded, speed control works as in M3.
When the secondary storage is loaded, speed control works as in M2.
Settings range: M1,M2,M3, M4, Off / Default: Off
This function should only be activated by a specialist. Depending on the pump and pump
stage used, the minimum speed should not be set too low, because otherwise the pump or
the system may be damaged. The information provided by the relevant manufacturer must
also be observed! If in doubt, the min. speed and the pump stage should generally be set to
high rather than too low.
Caution
6.3.2. - Purging time
During this time period, the pump is running with full speed (100%) to ensure trouble-free startup. After this
time has passed, the pump is set to speed control and is set to max. speed or min speed, depending on the
speed control variant „6.3.1. - Modes“ on page 27 chosen.
Settings range: 5 to 600 seconds / Default setting: 8 seconds
6.3.3. - Sweep time
Sweep time determines the inertia of the speed control to prevent strong fl uctuations in temperature.
Sweep time is the timespan for a complete change from minimum to maximum pump speed.
Settings range: 1 to 15 minutes / Default setting: 4 minutes
