Carrier OPN PSM MPCXPE Application Guide v2
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Carrier ChillerVu Variable Flow Condenser Pump CARRIER CORPORATION 2020
Application Guide i All rights reserved
Carrier ChillerVu Variable Flow Condenser Pump
Application Guide
CARRIER CORPORATION 2020 Catalog No. 11-808-577-01 12/17/2020
Verify that you have the most current version of this document from www.hvacpartners.com or
www.accounts.ivusystems.com or your local Carrier office.
Important changes are listed in Document revision history at the end of this document.
CARRIER CORPORATION 2020. All rights reserved throughout the world. i-Vu is a registered trademark of Carrier
Corporation. All other trademarks are the property of their respective owners.
Contents What is the Carrier ChillerVu variable flow condenser water pump application? ............................................ 1
Theory of operation .............................................................................................................................................. 3
Variable flow, headered condenser pump control sequence ................................................................................... 4 Points and Properties ........................................................................................................................................... 5
Manager Status ..................................................................................................................................... 5 Staging of pumps .................................................................................................................................. 6 Staging Trip Points and Delays ............................................................................................................. 7 Pump VFD Control - Differential Pressure Control Loop...................................................................... 7 Individual Pump Control - Configuration .............................................................................................. 9 Common CW Entering Temperature .................................................................................................. 10 Individual CW Flow Valve Control ....................................................................................................... 11 Individual Chiller Flow Configuration - Chiller Flow Meter ................................................................. 12 Individual Pump Control - Configuration ............................................................................................ 13
Variable flow, dedicated condenser pumps control sequence .............................................................................. 14 Points and Properties ........................................................................................................................................ 15
Manager Status ................................................................................................................................... 15 Common CW Entering Temperature .................................................................................................. 16 Individual Pump Control - Configuration - Pump Control .................................................................. 17 Individual Pump Control - Configuration - Pump VFD Control ........................................................... 18 Individual Pump Command Points - Configuration ............................................................................ 19 Optional Flow Meter Properties .......................................................................................................... 20
Document revision history ........................................................................................................................................ 21
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Application Guide 1 All rights reserved
The variable flow condenser pump sequence, available for both headered and dedicated pump arrangements,
allows you to stage up to 8 VFD-equipped condenser water pumps.
NOTES
Each pump must be equipped with a flow check valve device (or 2-position isolation valve) to prevent reverse
flow through pumps that are not currently operating.
Currently, the dedicated pump sequence supports equal- or dissimilar-sized pumps. The headered version
supports only equal-sized pumps, but dissimilar-sized pump logic will be available in a future release.
What is the Carrier ChillerVu variable flow condenser water pump application?
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CAUTION You can use the following applications and equipment files with the Carrier ChillerVu controller
ONLY.
You can find detailed information on the capabilities of the Carrier ChillerVu hardware in the Carrier
ChillerVu Installation and Start-up Guide (#11-808-532-01).
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Theory of operation
This theory of operation is based on the fact that condenser water Delta temperature (Delta T) across the
condenser barrel varies with the water flow rate through the condenser barrel.
The Variable Flow Condenser Loop Pump sequence saves condenser pump energy by reducing condenser
water flow through the chiller as machine load decreases.
Each chiller will have a design Delta T that represents the temperature rise through the condenser at full load
and the design condenser water flow rate. Varying the water flow rate as the load decreases, so that the
Delta T is maintained at the design value, can reduce pump energy consumption, while allowing the machine
to operate within its specified design parameters for heat rejection. You can set minimum and maximum
pump speeds and/or flow rates to ensure that maximum flow rate is never exceeded and a minimum flow
rate is maintained.
Example A machine with a 10F water temperature rise across the condenser barrel, under design
conditions, might only have a 5F rise at 50% load, if condenser water flow remains constant. By reducing
the condenser water flow in response to reduced Delta T, and causing it to increase to the original design
delta T of 10F, directly reduces pump energy consumption.
The system is designed to operate independently of tower control logic. During design conditions with high
outdoor wet bulb temperatures and high entering condenser water temperatures, the system has a safety
override that controls the pump VFD to maintain a maximum leaving condenser water temperature setpoint,
if the entering water temperature plus the delta T exceeds this value.
This causes the VFD to operate at higher speeds when the entering water is very high, or greater than the
allowable limit according to the machine design, and permits maximum flow through the condenser barrel,
until the leaving water temperature is brought down below the maximum setpoint. Once the entering
condenser temperature is below the specified high limit, the pumps' speeds and/or flow control valves will
again modulate to maintain the Delta T setpoint.
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Control sequence
1 The associated Chiller Manager (CM) program is linked to the Condenser Pump Manager (CPM) program
using a network point.
2 When chilled water is required, the CM signals the CPM, indicating how much condenser water flow is
required.
3 The CPM, based on the available capacity of its condenser pumps, starts the required number of pumps to
satisfy the CMs flow requirements. You can configure the run order and rotation behavior of the pumps.
4 Once the pumps are started, the VFD control sequence is enabled, which operates the pumps in unison to
maintain the required Delta P across the entire condenser system.
5 The 2-way, modulating flow control valve on each condenser inlet is regulated to maintain a target design
condenser Delta T for each chiller system.
6 If present, the optional flow meter on each branch will be used to set a minimum and maximum flow rate and
override the flow control valve output.
Variable flow, headered condenser pump control sequence
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Points and Properties
The following pages show the drop-down sections on the Properties > Control Program tab in the i-Vu interface.
Most of the properties are self-explanatory, however, certain key features, functions, and specific parameters are
defined.
The properties are shown in the order that they appear in your i-Vu interface. Properties that are not unique to
this application, such as Rotation and Reset, are omitted.
The CPM program can support a maximum of 8 condenser pumps. This document shows 1 example of each
properties section, since pumps 2 through 8 are the same.
Manager Status
Manager Status provides a status matrix and the option to enable or disable the pump manager.
When Enable Pump Manager is Yes, the program controls the pumps as shown.
When No, all pumps are disabled.
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Staging of pumps
Required Flow from Chiller Mgr the required flow value linked to the CMP from the CM
The maximum flow rate for EACH pump is __ gpm you can specify the maximum flow rate available from
each pump, resulting in the sequence calculating the maximum system flow rate available, based on the
number of pumps.
Requested number of pumps is: indicates the requested and actual number of running pumps
Lock number of pumps to run to __: locks the sequence to operate a specific number of pumps
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Staging Trip Points and Delays
Displays the status and delays of the lead pump and first lag pump.
Stages 3 through 8 are listed in sequence.
Pump VFD Control - Differential Pressure Control Loop
The pump VFDs are controlled in unison to maintain the differential pressure setpoint you enter. The Delta P is
measured across the system headers.
VFD control parameters:
Diff Pressure setpoint
VFD Minimum Output speed
Control Output Override override values
High Differential Pressure Protection setpoints and actions
Alarms settings for the VFD control
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Individual Pump Control - Configuration
These properties display each pump's operational status data with values you can configure.
Pump Maintenance Mode
Normal - pump remains under the control of the CPM program
Maintenance - pump is no longer under the control of the CPM program
Re-enable - re-starts operation
Convert the PID values in the range sets the scaling of the VFD output to match the prevailing frequency (50Hz
or 60Hz)
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Common CW Entering Temperature
The key parameter in this section is the maximum entering condenser water temperature, which is used to
override the Flow Control Valve Output to 100%.
The maximum Flow Control Valve Output is overridden to 100% when the entering condenser water sensor
exceeds the high temperature limit the you specify.
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Individual CW Flow Valve Control
Chiller 1 CW Flow Valve Control
The CW Flow Valve Effective Minimum and Maximum Position Setpoints only show if you select the optional Flow
Meters at build time.
The settings and status values related to the flow control valve for each condenser are displayed. If no flow meters
are installed, you can set a minimum valve position so that minimum flow is maintained during startup and low
loads.
You can set the following:
Delta Temperature Setpoint The Delta T is calculated from the common condenser entering water setpoint
and the individual condenser water leaving temperature.
CW Flow Valve Minimum Position Setpoint use when Flow Meters are not installed
CW Flow Valve Maximum Position Setpoint use when Flow Meters are not installed
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Individual Chiller Flow Configuration - Chiller Flow Meter
You can select flow meters in EquipmentBuilder when making your control program. If you have not selected
them, this property section is absent.
If you use flow meters, the CPM calculates minimum and maximum flow valve positions, based on the measured
flow and the minimum and maximum flow setpoints you define.
The value that is assigned to the flow control valve will be:
The larger of the calculated minimum or your defined minimum flow value
The smaller of the calculated maximum or your defined maximum flow value
IMPORTANT
We highly recommend that when using flow meters, you set the Maximum Valve position to 100% and the
Minimum Valve Position to 10% to make sure that the condenser water flow values are used and not
overridden by the configured valve position limits.
You must set the Minimum and Maximum CW Flow Setpoint values in accordance with the chiller design
specifications, to ensure that acceptable levels of flow are always maintained whenever a chiller is operating.
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Individual Pump Control - Configuration
All input and output points for the individual pumps are displayed and available as hardware or network points.
NOTE The Chiller Enable point provides chiller status to the CPM and should be connected to a point in the
system that can provide individual Chiller Run Status.
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NOTES
The variable flow, dedicated condenser pump sequence is a simplified version of the Variable flow, headered
condenser pump control sequence (page 4).
Run order or rotation logic is not necessary because the sequence requires dedicated pumps (each pump is
directly linked to a specific chiller). Also, the associated Chiller Manager does not need to send flow
requirements to the Condenser Pump Manager.
Each pump must be equipped with a flow check valve device or a 2-position isolation valve to prevent reverse
flow through pumps that are not currently operating.
If you have specified optional flow meters, the configuration screens are shown at the end of this document.
Control Sequence
1 The associated Chiller Manager (CM) program is linked to the Condenser Pump Manager (CPM) program
using network or hardware points.
2 When the CM needs to start a chiller, the logic enables the corresponding Run Pump point, followed by
enabling the corresponding condenser pump.
3 Once a pump is started, the associated VFD control sequence is enabled, which operates the pump to
maintain your defined condenser Delta T.
NOTE Each chiller/pump pair operates independently.
4 For systems equipped with flow meters, you can specify minimum and maximum flow settings. These values
override the VFD settings selected by the temperature control logic. This ensures that minimum and
maximum flow values are never exceeded.
Variable flow, dedicated condenser pumps control sequence
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Points and Properties
The following pages show the drop-down sections on the Properties > Control Program tab in the i-Vu interface.
Most of the properties are self-explanatory, however, certain key features, functions, and specific parameters are
defined.
The properties are shown in the order that they appear in your i-Vu interface. Properties that are not unique to
this application, such as Rotation and Reset, are omitted.
The CPM program can support a maximum of 8 condenser pumps. This document shows 1 example of each
properties section, since pumps 2 through 8 are the same.
Manager Status
Manager Status provides a status matrix and the option to enable or disable the pump manager.
When Enable Pump Manager is Yes, the program controls the pumps as shown.
When No, all pumps are disabled.
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Common CW Entering Temperature
The key parameter in this section is the maximum entering condenser water temperature, which is use to override
the VFD Output to 100%.
The maximum VFD Output is overridden to 100% when the entering condenser water sensor exceeds the high
temperature limit that you specify.
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Individual Pump Control - Configuration - Pump Control
These properties display each system pump's operational status data and values you can configure.
Pump Maintenance Mode
Normal - pump remains under the control of the CPM program
Maintenance - pump is no longer under the control of the CPM program
Re-enable - re-starts operation after failure
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Individual Pump Control - Configuration - Pump VFD Control
In the Pump VFD Control parameters, you can configure settings that relate to the VFD control sequence,
including Delta T setpoint, and minimum and maximum output values. You must set the minimum and maximum
output values in accordance with the chiller design specifications to ensure that acceptable levels of flow are
always maintained whenever a chiller is operating.
Set the scaling of the VFD output to match the prevailing frequency (50hZ or 60hZ).
The settings are available in this properties section when flow meters were not selected in EquipmentBuilder.
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Individual Pump Command Points - Configuration
All input and output points for the individual pumps are displayed and available as hardware or network points.
NOTE The Run Pump point provides a pump start to the CPM and should be connected to a point in the system
that signals the start of the corresponding condenser pump. On chillers with local pump control, a hardware or
network point typically starts the condenser pump.
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Optional Flow Meter Properties
When optional flow meters are specified, the Pump VFD Control section replaces the previous page, and a new
Properties section for the actual flow meter is added to the program. This includes information relating to the flow
meter min/max flow override sequence.
IMPORTANT
We highly recommend that when using flow meters, you set the Maximum VFD Speed Setpoint to 100% and
the Minimum VFD Speed Setpoint to 10% to make sure that the condenser water flow values are used and
not overridden by the configured valve position limits.
You must set the Minimum and Maximum CW Flow Setpoint values in accordance with the chiller design
specifications, to ensure that acceptable levels of flow are always maintained whenever a chiller is operating.
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Application Guide 21 All rights reserved
Important changes to this document are listed below. Minor changes such as typographical or formatting errors are not
listed.
Date Topic Change description Code*
6/20/19 Entire book. Removed "Proprietary and Confidential" from the footer C-D
10/5/16 Common CW Entering Temperature -
Headered
Calrified explanation. X-AE-BL-E
Common CW Entering Temperature -
Dedicated
Screen capture corrected and text changed to reflect that
dedicated pumps do not have a flow control valve.
X-AE-BL-E
* For internal use only
Document revision history
CARRIER CORPORATION 2020 Catalog No. 11-808-577-01