Operating instructions

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
Disabled [0], the par. 25-30 Destage Function Time
will not be 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 par. 4-11 Motor
Speed Low Limit [RPM] or par. 4-12 Motor Speed Low
Limit [Hz], with one or more fixed speed pumps in
operation and 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.
3.23.3 25-4* Staging Settings
Parameters determining conditions for staging/destaging the
pumps.
25-40 Ramp Down Delay
Range: Function:
10.0 s * [0.0 -
120.0 s]
When adding a fixed speed pump controlled by
a soft 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.
Only to be used if Soft Starter [1] is selected in
par. 25-02 Motor Start.
25-41 Ramp Up Delay
Range: Function:
2.0 s * [0.0 -
12.0 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
stopping of the fixed speed pump to eliminate
pressure surges or water hammer in the system.
Only to be used if Soft Starter [1] is selected in
par. 25-02 Motor Start.
Parameter Description
VLT
®
HVAC Drive Programming Guide
MG.11.CA.02 - VLT
®
is a registered Danfoss trademark 171
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