System Settings; Motor Start; Pump Cycling; Fixed Lead Pump - Danfoss VLT Programming Manual

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VLT HVAC Drive Programming Guide

3.23.2 25-0* System Settings

Parameters related to control principles and configuration of the system.
25-00 Cascade Controller
Option:
[0] * Disabled
[1] Enabled

25-02 Motor Start

Option:
[0] * Direct on Line
[1] Soft Starter

25-04 Pump Cycling

Option:
[0] * Disabled
[1] Enabled

25-05 Fixed Lead Pump

Option:
[0] No
[1] * Yes
Function:
For operation of multiple devices (pump/fan) systems where capacity is adapted to actual load by
means of speed control combined with on/off control of the devices. For simplicity only pump sys-
tems are described.
The Cascade Controller is not active. All built-in relays assigned to pump motors in the cascade
function will be de-energized. If a variable speed pump is connected to the frequency converter
directly (not controlled by a built-in relay); this pump/fan will be controlled as a single pump system.
The Cascade Controller is active and will stage/destage pumps according to load on the system.
Function:
Motors are connected to the mains directly with a contactor or with a soft starter. When the value
Motor Start
of par. 25-02 is set to an option other than
Pump Alternation
is automatically set to the default of
Each fixed speed pump is connected to line directly via a contactor.
Each fixed speed pump is connected to line via a soft starter.
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 frequency con-
verter and if a contactor is applied between frequency converter and pump, this contactor will not
be controlled by the frequency converter.
If operating with par. 25-50 Lead Pump Alternation
be 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 frequency converter).
The lead pump will be fixed (no alternation) and connected directly to the frequency converter. The
Lead Pump Alternation
par. 25-50
2 can be assigned to separate fixed speed pumps. In total three pumps can be controlled by the
frequency converter.
MG.11.C9.02 - VLT ® is a registered Danfoss trademark
3 Parameter Description
Direct on Line
Direct on Line
[0].
set to other than Off
Off
is automatically set to [0]. Built-in relays Relay 1 and Relay
3
Lead
[0], then par. 25-50
[0], this parameter must
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