English (GB)
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8.7.19 Pump start and stop speed (4.2.8)
Description
The function controls the starting and stopping of pumps.
There are two options:
1. Use calculated speed
This function ensures that the optimum number of pumps is
always running at a desired duty point, in terms of energy
consumption. The CU 352 calculates the required number of
pumps and their speed. This requires that the differential
pressure of the pump is measured by a differential-pressure
sensor or separate pressure sensors on the inlet and
discharge side.
If calculated speed has been selected, the CU 352 will ignore
the percentages set.
2. Use fixed speed
The pumps are started and stopped at speeds set by the user.
1. Use calculated speed
Fig. 59
Use calculated speed
Setting via control panel
• Settings > Pump cascade control > Pump start and stop speed
> Use calculated speed.
2. Use fixed speed
Fig. 60
Use fixed speed
Setting via control panel
• Settings > Pump cascade control > Pump start and stop
speed.
• Select: Use fixed speed.
• Set: Start next pump at this speed > 1 -> 2.
1. Set the speed as percentage.
2. Set the other pumps in the same way.
3. Select: Instant pump stop at > 1 -> 0.
4. Set the speed as percentage.
5. Set the other pumps in the same way.
Factory setting
The function is set to calculated speed.
8.7.20 Min. performance (4.2.9)
Fig. 61
Min. performance
Description
This function ensures circulation in a system. Note that the stop
function, if enabled, can influence this function.
See section
. Examples:
• If 0 pumps have been selected, the stop function can stop the
pump if there is no or a very small consumption.
• If pumps have been selected, the stop function will not be
active.
Setting via control panel
• Settings > Pump cascade control > Min. performance.
1. Set:
• Number of pumps
• Speed.
Factory setting
The number of pumps is set to 0. The speed in closed loop is set
to 25 %.
