25-26 Destage At No-Flow
Option:
Function:
This parameter ensures that when a no-flow
situation occurs, the fixed speed pumps are
destaged 1 by 1 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
s
*
[0 -
300 s]
The stage function time is programmed to avoid
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 runs 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 1 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
is not activated.
[0] Disabled
[1] Enabled
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 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 1 or
more fixed speed pumps in operation and system
25-30 Destage Function Time
Range:
Function:
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.
e75za640.12
(4-12)
(27-27)
F
min
F VLT pump
Destage
timer period
Pump
switch-off
Illustration 3.87 Destage Function Time
3.22.3 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 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. 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
25-41 Ramp Up Delay
Range:
Function:
2 s
*
[0 -
12 s]
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 stop of
the fixed 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 Description
Programming Guide
MG20OB02
Danfoss A/S © 05/2018 All rights reserved.
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Summary of Contents for VLT AQUA Drive FC 202
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