Danfoss VLT AQUA Drive FC 202 Programming Manual page 179

Parameter Description
25-26 Destage At No-Flow
Option: Function:
The Destage at No-Flow parameter ensures that
when a no-flow situation occurs, the fixed speed
pumps are destaged one-by-one until the no-flow
signal disappears. This requires that No Flow
Detection is active. See parameter group 22-2* No-
Flow Detection.
If [0] Disabled is selected, the cascade controller
does not change the normal behavior of the
system.
[0] Disabled
[1] Enabled
25-27 Stage Function
Option: Function:
If the Stage Function is set to [0] Disabled,
parameter 25-28 Stage Function Time is not
activated.
[0] Disabled
[1] Enabled
25-28 Stage Function Time
Range: Function:
15 [0 - The Stage Function Time is programmed to avoid
s 300 s] frequent staging of the fixed speed pumps. The
*
Stage Function Time starts if it is [1] Enabled by
parameter 25-27 Stage Function, and when the
variable speed pump is running at Motor Speed
High Limit, parameter 4-13 Motor Speed High Limit
[RPM] or parameter 4-14 Motor Speed High Limit [Hz],
with at least one fixed speed pump in the stop
position. When the programmed value of the timer
expires, a fixed speed pump is staged.
25-29 Destage Function
Option: Function:
The destage function ensures that the lowest
numbers of pumps are running to save energy and
to avoid dead head water circulation in the
variable speed pump. If the destage function is set
to [0] Disabled, parameter 25-30 Destage Function
Time is not activated.
[0] Disabled
[1] Enabled
25-30 Destage Function Time
Range: Function:
15 [0 - The destage function timer is programmable to
s 300 s] avoid frequent staging/destaging of the fixed 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 one
or more fixed speed pumps in operation and
MG20O702
Programming Guide
25-30 Destage Function Time
Range:
F VLT pump
F
min
(4-12)
Illustration 3.79 Destage Function Time
3.22.3 25-4* Staging Settings
Parameters determining conditions for staging/destaging
the pumps.
25-40 Ramp Down Delay
Range:
10 s
*
120 s]
25-41 Ramp Up Delay
Range:
2 s [0 -
*
12 s]
Danfoss A/S © Rev. 2014-01-21 All rights reserved.
Function:
system requirements satisfied. 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.
Pump
switch-off
De-stage
timer period
(27-27)
Function:
[0 - When adding a fixed 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 fixed speed
pump to eliminate 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.
Function:
When removing a fixed 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
stopping of the fixed speed pump to eliminate
pressure surges or water hammer in the system.
Only to be used if [1] Soft Starter is selected in
parameter 25-02 Motor Start.
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