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VLT
®
HVAC Drive Programming Guide
25-04 Pump Cycling
Option:
[0] *
Disabled
[1]
Enabled
25-05 Fixed Lead Pump
Option:
[0]
No
[1] *
Yes
25-06 Number Of Pumps
Range:
2 N/A*
[2 - 9. N/A]
Function:
To provide equal hours of operation with fixed speed pumps, the pump use can be cycled. The
selection of pump cycling is either "first in – last out" or equal running hours for each pump.
The fixed speed pumps will be connected in the order 1 – 2 and disconnected in the order 2 – 1.
(First in – last out).
The fixed speed pumps will be connected/disconnected to have equal running hours for each pump.
Function:
Fixed Lead Pump means that the variable speed pump is connected directly to the adjustable fre-
quency drive, and if a contactor is applied between adjustable frequency drive and pump, this
contactor will not be controlled by the adjustable frequency drive.
If operating with par.25-50
Lead Pump Alternation
set to
No
[0].
The lead pump function can alternate between the pumps controlled by the two built in relays. One
pump must be connected to the built-in RELAY 1, and the other pump to RELAY 2. The pump
function (Cascade Pump1 and Cascade Pump2) will automatically be assigned to the relays (maxi-
mum two pumps can in this case be controlled from the adjustable frequency drive).
The lead pump will be fixed (no alternation) and connected directly to the adjustable frequency
drive. The par.25-50
Lead Pump Alternation
and Relay 2 can be assigned to separate fixed speed pumps. A total of three pumps can be controlled
by the adjustable frequency drive.
Function:
The number of pumps connected to the cascade controller including the variable speed pump. If
the variable speed pump is connected directly to the adjustable frequency drive and the other fixed
speed pumps (lag pumps) are controlled by the two built-in relays, three pumps can be controlled.
If both the variable speed and fixed speed pumps are to be controlled by built-in relays, only two
pumps can be connected.
par.25-05 Fixed Lead Pump, Fixed Lead Pump
If
fixed speed pump; both controlled by a built-in relay. If
Pump
Yes
, is set to
[1]: one variable speed pump and one fixed speed pump controlled by a built-
in relay.
One lead pump, see par.25-05
relays.
MG.11.C6.22 - VLT
®
is a registered Danfoss trademark
set to other than
Off
is automatically set to
Off
No
, is set to
[0]: one variable speed pump and one
par.25-05 Fixed Lead Pump, Fixed Lead
Fixed Lead Pump
. Two fixed speed pumps controlled by built-in
3 Parameter Description
3
[0], this parameter must be
[0]. Built-in relays Relay 1
3-237
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