Danfoss vlt FC 102 - Page 242

25-30 Destage Function Time
Range: Function:
15 s* [0 - 300 s] The destage function timer is
programmable to avoid frequent
staging/destaging of the xed-
speed pumps. The destage function
time starts when the adjustable-
speed pump is running at
parameter 4-11 Motor Speed Low
Limit [RPM] or parameter 4-12 Motor
Speed Low Limit [Hz], with 1 or
more xed-speed pumps in
operation and system requirements
satised. In this situation, the
adjustable-speed pump contributes
a little to the system. When the
programmed value of the timer
expires, a stage is removed,
avoiding dead head water
circulation in the adjustable-speed
pump.
e75za640.12
(4-12)
(27-27)
F
min
F
VLT pump
Destage
timer period
Pump
switch-off
Illustration 3.81 Destage Function Time
3.23.3 25-4* Staging Settings
Parameters determining conditions for staging/destaging
the pumps.
25-40 Ramp Down Delay
Range: Function:
10 s* [0 - 120 s] When adding a xed-speed pump
controlled by a soft starter or a
star-delta starter, it is possible to
delay the ramp down of the lead
pump until a preset time after the
start of the xed-speed pump. This
delay eliminates pressure surges or
water hammer in the system.
Use this option only if [1] Soft
Starter or [2] Star Delta is selected
in parameter 25-02 Motor Start.
25-41 Ramp Up Delay
Range: Function:
2 s* [0 - 12 s] When removing a xed-speed
pump controlled by a soft starter, it
is possible to delay the ramp up of
the lead pump until a preset time
after the stop of the xed-speed
pump. This delay eliminates
pressure surges or water hammer in
the system.
Only to be used if [1] Soft Starter is
selected in parameter 25-02 Motor
Start.
Parameter Descriptions
VLT
®
HVAC Drive FC 102
240 Danfoss A/S © 10/2019 All rights reserved. M0010001
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