25-26 Destage at No-Flow
Option:
Function:
[0]
*
[1]
Disabled
Enabled
The Destage at No-Flow parameter ensures that when a no-flow
situation occurs, the fixed speed pumps will be destaged one-
by-one until the no-flow signal disappears. This requires that No
Flow Detection is active. See par. 22-2*.
If Destage at No-Flow is disabled the cascade controller does
not change the normal behaviour of the system.
25-27 Stage Function
Option:
Function:
[0]
Disabled
[1]
*
Enabled
If the Stage Function is set to
Disabled
[0],
Stage Timer
, par.
25-28, will not be activated.
25-28 Stage Function Time
Range:
Function:
15 sec.
*
[0 – 300 sec.]
The Stage Function Time is programmed to avoid frequent stag-
ing of the fixed speed pumps. The Stage Function Time starts if
it is
Enabled
[1] by
Stage Feature
, par. 25-27, and when the
variable speed pump is running at
Motor Speed High Limit
, par.
4-13 or 4-14, 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:
[0]
Disabled
[1]
*
Enabled
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
Destage Timer
, par. 25-30, will not be
activated.
25-30 Destage Function Time
Option:
Function:
[15
sec.]
*
0 – 300 sec.
The Destage Function Timer is programmable to avoid frequent
staging/destaging of the fixed speed pumps. The Destage Func-
tion Time starts when the adjustable speed pump is running at
Motor Speed Low Limit
, par. 4-11 or 4-12, with one or more
fixed speed pumps in operation and system requirements sat-
isfied. 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 circula-
tion in the adjustable speed pump.
VLT
®
AQUA Drive Programming Guide
2. Parameter Description
MG.20.O2.02 - VLT
®
is a registered Danfoss trademark
233
2