valent 484755 Supplement Microprocessor Controller User Manual

Document 484755
Heat-Cool Only Controls for
Dedicated Outdoor Air System

484755 Supplement Microprocessor Controller

Supplement Microprocessor Controller
Please read and save these instructions for future reference. Read carefully before attempting to assemble, install, operate or maintain the product described. Protect yourself and others by observing all safety information. Failure to comply with these instructions will result in voiding of the product warranty and may result in personal injury and/or property damage.

Overview

This document is to be used in conjunction with the Microprocessor Controller for Dedicated Outdoor Air System Installation, Operation and Maintenance Manual (IOM). All safety information provided in that IOM pertains to Heat- Cool Only controls also.
Heat-Cool Only Overview
Heat-Cool Only is designed to allow third-party control of a packaged DX, or Heat Pump unit while maintaining the safeties of the refrigeration system and heating devices. To achieve this, the Heat-Cool Only controller is factory installed and factory commissioned. This controller is responsible for the operation of the refrigeration and heating components installed in the unit. The safety of the refrigeration system is assured by monitoring pressures and temperatures contained within the refrigeration circuit(s). The third party is required to control the following: supply and exhaust airflow, cooling or heating operation selection, dehumidification enable, temperature setpoints, and emergency shutdown.
Additionally, a third-party device that is field supplied and installed provides occupancy, temperature, and airflow monitoring. This third-party device interfaces to the Heat-Cool Only controller via a terminal strip in the control cabinet, as represented in the image below.
END DEVICES: End devices required for Heat-Cool Only operation are provided and installed in the unit for the sole purpose of operating the heat/cooling control system. Sensors required for the third-party controller operation are to be provided and installed by the third party. Additionally, the third-party control system may use additional end devices not provided by the factory. Please refer to the unit’s submittal information for the exact unit configuration and selected options to determine factory provided end devices.
WARNING
Powering the third-party controller is the responsibility of the third party. The third party will supply and install a transformer to power their controller. This power cannot be taken from the control panel. The third-party device cannot be mounted in the electrical control panel of the unit.

Third Party Responsibilities

Occupancy, temperature, airflow, and third-party device power with Heat-Cool Only are the responsibility of the third party through a third-party device. This control not
only includes the timing of each occupied mode, but logic for enabling and modulating all non-refrigeration or heating components.
Occupancy
Scheduling and occupancy mode control are the responsibility of the third party.
Airflow
Maintaining the proper airflow by enabling and modulating the fans and dampers is the responsibility of the third-party controller.
During normal operation, airflow should continue over the unit’s heat exchangers after removing the remote start command to the Heat-Cool Only controller. For units with variable speed compressors, the compressors may take up to two minutes to completely stop. Additionally, in heating mode, supply airflow should continue until the supply air temperatures drop below 80ºF to dissipate the heat remaining in the heating devices and prevent excessive component temperatures.
DAMPER POSITIONING: Dampers will need to be powered and a position signal provided, when the dampers are modulating. Prior to starting fans in the unit, the third party will ensure that there is an open path for airflow by confirming that the damper end switch is closed, when installed.
FAN MODULATION: The enable and modulation signals are the responsibility of the third-party controller.

• Supply Fan: Supply fan modulation will need to follow these guidelines. The end switch signal must be received prior to the start of any fans in the unit when installed.

  • Cooling or Heat Pump Heating: When the unit is operating in cooling mode or heat pump heating, the fan turndown must be limited to a minimum of 50% of the designed airflow to ensure the refrigeration system can adequately modulate to meet the desired temperature setpoints. Modulating below 50% of the designed airflow may result in loss of space temperature control and have a negative impact on the refrigeration and heating components.

  • Electric Heat: Supply fan modulation must be limited to the minimum airflow requirements of the electric heater manufacturer. The minimum air flow required through a duct heater depends on the KW per square foot of face area for the highest capacity ON-OFF stage. In general, 500 FPM is adequate in most applications. Please contact technical support to get more information regarding specific products.
    WARNING
    When modulating the gas furnace heating capacity, it is recommended to maintain a maximum temperature rise and a minimum airflow for all units. The criteria must be met when controlling the staging and modulation of the gas furnaces in order to prevent improper combustion and damage to the unit.
    Please see Appendix B – Heat-Cool Only Heating Limitations for minimum airflow specific to the unit size and furnace installed.
    Please refer to the unit’s submittal information for the exact gas furnace performance data.

  • Gas Furnace Heat: When the unit is heating with a gas furnace, limit turndown to the minimum airflow based on the unit size or 50.0% of design airflow, whichever value is greater.
    Please see Appendix B – Heat-Cool Only Heating Limitations for minimum airflow specific to the unit size and furnace installed.

• Exhaust fan: Exhaust fan modulation will need to maintain the building requirements.

Energy Recovery
Control of energy recovery equipment installed in the unit is the responsibility of the third party. A heat wheel with or without a VFD, a core with face/bypass dampers or a bypass only damper must be controlled to a thirdparty provided sensor.
ENERGY WHEEL BYPASS DAMPER: When provided, the energy wheel bypass damper needs to be opened when exceeding design outdoor airflow rate in economizer mode by turning off the energy recovery wheel.
ENERGY CORE DAMPERS: When selected, the energy core may have either face and bypass dampers or only a bypass damper.

• Face/Bypass Dampers: When face and bypass dampers are both installed, the signal to the actuator would be 2-10V that is the desired for energy recovery. The signal in this situation is controlling the face damper and the bypass is the inverse of the signal.
• Bypass Only Damper: When only a bypass damper is installed, the signal to the actuator would be 2-10V also. However, the signal is the opposite of the desired for energy recovery. If 80% energy recover is desired, then the signal to the bypass damper should be 20% or 2 volts. The signal is controlling the bypass damper.

ENERGY RECOVERY DEFROST: Both forms of energy recovery must have a defrost sequence provided via the third-party controller.

• Energy Recovery Wheel: The third party will provide either an exhaust air temperature sensor or heat wheel pressure differential sensor/switch when pre-heat is not installed in the unit and the energy recovery device is used for exhaust air energy recovery. The exhaust air temperature must remain above 36°F or the differential pressure is less than 1.5”wc when the outside air temperature is below 10°F.
• Energy Core: The third party will provide an exhaust air temperature sensor when pre-heat is not installed in the unit and the energy recovery device is used for exhaust air energy recovery. The exhaust air temperature must remain above 36°F.
• Electric Preheat: When a preheat device is installed for energy recovery defrost, the third-party controller needs to ensure that the following conditions are met prior to enabling the preheat device.
  • Outside Air Damper >=30% open; AND
  • Supply Fan enabled; AND
  • Outdoor Air Temp < 10°F.

NOTE: Please see manufacturer’s information for suggested minimum cfm for pre-heat.
Temperature
Heat-Cool Only Control requires the third party to make decisions based on operating conditions and setpoints to heat, cool, dehumidify, or economize.
The third-party controller will communicate setpoints, via hard-wired 2-10 VDC signals, based on the operating mode:

• Cooling – Cooling Coil Setpoint
• Dehumidifying – Cooling Coil and Supply Air Setpoints
• Heat Pump Heating – Supply Air Setpoint
• Heating – Supply Air Setpoint

The third-party controller needs to control the amount of economizer and energy recovery capacity necessary to meet the current requirements, depending on the equipment installed in the unit. Analog output signals are sent via the terminal strip that interfaces with the controller or directly to the end devices.
Please refer to the unit wiring schematics or see Appendix A – Terminal Strip Wiring for further information regarding control input types and terminal strip wiring.

• Cold Coil Temperature Control: The thirdparty controller will send a signal to controlthe compressors in the unit. This setpoint will range between 50ºF and 75ºF in cooling and dehumidification modes of operation.

• Supply Air Temperature Control: When the unit has a HGRH coil or heating, there will be a Supply Air Temperature Setpoint input for the third-party controller. This setpoint will range between 50°F and 95°F in all modes of operation. The HGRH valve and heating devices will control to this setpoint.
  NOTE: A minimum setpoint of 60.0°F is advised in heating mode of a heat pump.

• Supply Temperature Limits: The heat-cool only controller also has high and low temperature limits. These limits are adjustable at the controller and will cause cooling or  eating to be isabled. It is the responsibility of the third party to maintain the following conditions:

  • Minimum Low Supply Temp Limit: 35°F
  • Maximum High Supply Temp Limit: 120°F

• Mode Switching – Cooling vs Heating:
  When heating and cooling are both installed in the unit, the third party is responsible for determining which mode of operation is required at any given time. The Cooling/Heating Control Mode input will be open for cooling or closed for heating. When the input changes state, the unit will shut down the current operation of the
  cooling or heating devices and switch to the other mode of operation after the mode switch timer expires.

• Mode Switching – Cooling vs
  Dehumidification: When a hot gas reheat coil is installed in the unit, the third party is responsible for determining when the hot gas reheat will control to the Supply Air Temperature Setpoint. The Cooling/Dehumidification Control Mode input will be open for cooling only or closed when reheat is desired.

Digital Status
The Heat-Cool Only terminal strip provides the third-party controller with information from devices installed in the unit. The following information is available through those digital statuses.
OUTSIDE AIR DAMPER ACTUATOR END
SWITCH: When installed, this status provides an indication that the outside air damper actuator has reached a specific open position.
CONDENSATE OVERFLOW SWITCH: This
device, when installed, indicates when the condensate drain pan is full and further operation of the refrigeration system could cause an overflow of water in the pan.
ENERGY RECOVERY STATUS: When installed, the energy recovery device may have an indication back to the terminal strip that the device is rotating, or the bypass is open.
FILTER PRESSURE SWITCH: If a filter pressure switch or switches is installed, an indication back to the third-party indicates that the filters are dirty.
GLOBAL ALARM OUTPUT: The global alarm output is available on all Heat- Cool Only units. This status indicates that there is an alarm condition in the HeatCool Only controller.
Digital Commands
EMERGENCY SHUTDOWN: This input is to remotely shutdown the unit during a fault condition. All heating or cooling operation will stop when this input is open.
This input affects the Global Alarm status.
REMOTE START/STOP: This input is to remotely start or stop the refrigeration and heating control of the unit. This input will be closed for the unit to provide cooling or heating.
COOLING/DEHUMIDIFICATION CONTROL MODE: This input determines whether the unit is in cooling mode or dehumidification mode.
COOLING/HEATING CONTROL MODE: This input determines whether the unit is in cooling or heating mode.

Operation of Unit

All Modes
The following conditions are required for the third party to enable the unit to operate in any mode:

**NOTE: These safety checks are the responsibility of the third-party controller and do NOT input to the controller.
Cooling
The following conditions are required for the third party to enable the unit and start compressors in cooling mode:

Dehumidifying NOTE: Hot Gas Reheat must be installed in the unit to utilize this functionality.
The following conditions are required for the controller to enable a unit in dehumidification mode:

Heating
The following conditions are required for the controller to enable a unit in heating mode:

Heating – Heat Pump
The following conditions are required for the controller to enable a unit and start compressors in heating mode.

only)
• Refrigerant Pressure Switches:| Closed (High and low)
• Supply Air Temperature:| < Maximum High Supply Temp Limit (120.0°F)
• Supply Air Setpoint Request:| 50-95°F scaled from 2-10vdc

Appendix A: Terminal Strip Wiring

Third-Party Wiring
The following table/diagram is the terminal strip wiring of the terminal strip for Heat-Cool Only operation. This terminal strip is the wiring point for the third-party control’s device. Please refer to the unit schematics for additional information.

• This terminal position is for any energy recovery device, heat wheel, core with face/bypass dampers, or core with bypass only damperThe voltage for either core option is 2.0-10.0VDC.

Appendix B: Gas Furnace Limitations

Supply fan modulation must be limited to the minimum airflow based on the unit size or 50% of design airflow, whichever value is greater. When modulating the gas furnace heating capacity, it is recommended to maintain a maximum temperature rise and a minimum airflow for all units.
WARNING
The following criteria must be met when controlling the staging and modulation of the gas furnaces to prevent improper combustion and damage to the unit. The airflow  reduction is only allowed if the supply air temperature does not exceed the max temp rise listed below. The supply air temp must be monitored, and the furnace must be
modulated to prevent over-firing of the furnace at low airflows.

1. In the table below, locate the unit casing size, the correct furnace MBH, and the airflow supply direction for the minimum airflow in CFM.

2. All gas furnaces must be limited to the greater of the following:
   a. minimum airflow in CFM; OR
   b. 50% of design airflow.

3. The third-party controls will send a 2-10VDC signal to control to a supply air temperature setpoint between 50.0°F (10.0°C) and 95.0°F (35.0°C) during all modes of operation.

4. The third-party controls must have a high supply temperature limit of 120.0°F (48.8°C) that shuts down all heating sources within the unit when the supply air temperature is greater than or equal to this high supply temp limit.

5. Minimum Temp Rise of 20.0°F for all furnaces.

CFM
VPR-110| 100| 100.0°F| 741| 60.0°F| 1,235
150| 100.0°F| 1,111| 60.0°F| 1,852
200| 100.0°F| 1,481| 60.0°F| 2,469
VPR-210| 200| 100.0°F| 1,481| 60.0°F| 2,469
250| 100.0°F| 1,852| 60.0°F| 3,086
300| 100.0°F| 2,222| 60.0°F| 3,704
350| 100.0°F| 2,593| 60.0°F| 4,321
400| 100.0°F| 2,963| 60.0°F| 4,938
VPR-310| 400| 100.0°F| 2,963| 60.0°F| 4,938
500| 100.0°F| 3,704| 60.0°F| 6,173
600| 100.0°F| 4,444| 60.0°F| 7,407
700| 100.0°F| 5,186| 60.0°F| 8,642
800| 100.0°F| 5,926| 60.0°F| 9,877
VPR-352 VX-352 VXE-352| 600| 100.0°F| 4,444| 60.0°F| 7,407
800| 100.0°F| 5,926| 60.0°F| 9,877
1000| 100.0°F| 7,407| 60.0°F| 12,346
1200| 100.0°F| 8,889| 60.0°F| 14,815
VX-12| 75| 100.0°F| 556| 100.0°F| 556
100| 100.0°F| 741| 100.0°F| 741
150| 100.0°F| 1,111| 100.0°F| 1,111
200| 100.0°F| 1,481| 100.0°F| 1,481
VX-112| 100| 100.0°F| 741| 100.0°F| 741
200| 100.0°F| 1,481| 100.0°F| 1,481
300| 100.0°F| 2,222| 100.0°F| 2,222
VX-212| 300| 100.0°F| 2,222| 100.0°F| 2,222
400| 100.0°F| 2,963| 100.0°F| 2,963
500| 100.0°F| 3,704| 100.0°F| 3,704
VX-312| 600| 100.0°F| 4,444| 100.0°F| 4,444
800| 100.0°F| 5,926| 100.0°F| 5,926
1000| 100.0°F| 7,407| 100.0°F| 7,407
1200| 100.0°F| 8,889| 100.0°F| 8,889

Appendix C: Supply and Exhaust Airflow Calculations

Supply and Exhaust Fan Airflow Measurement
The third-party controller can use the transducer’s signal from the supply fan and/or from the exhaust fan and the airflow formula to determine the amount of current airflow.
FORMULA: CFM = k √(ΔP)
ΔP = Differential Pressure (0.0-30.0 in. wc scaled from 0.0 to 10.0 VDC reading from transducer)
k = K Factor (from table) # of Fans
√= Square Root
NOTE: The supply and exhaust airflow will be calculated separately. Only include the fans of the same type in the calculation.

Appendix D: Outside Air Damper Airflow Calculations

If airflow monitoring for the outside air damper is installed it could be one of two types of airflow. Each type has their own calculations and/or setup.
Outside AMD
The following table shows the unit casing and tonnage along with the model of the AMD-23 that would be used with the optional purchase of airflow monitoring of OAD. Select the proper Supply CFM Range to determine the values to use in the calculation. The values are also available on the AMD.
NOTE: The operating range for the AMD damper is 300 to 2000 fpm. Airflows outside of the operating range may not properly register

Outside AMD

Unit Casing| 110| 110| 210| 210| 310| 310| 352| 352
Supply CFM Range| < 2700| > 2700| < 5100| > 5100| < 8300| > 8300| < 13700| > 13700
Area| 1.75 ft2| 2.33 ft2| 3.33 ft2| 4.72 ft2| 5.43 ft2| 7.67 ft2| 9.17 ft2| 12.22 ft2
K Factor| 2699| 2697| 2716| 2714| 2748| 2747| 2813| 2812
M Value| 0.477| 0.477| 0.477| 0.477| 0.477| 0.477| 0.477| 0.477
Transducer Range| 0 – 0.5”wc| 0 – 1”wc| 0 – 0.5”wc| 0 – 1”wc| 0 – 0.5”wc| 0 – 1”wc| 0 – 0.5”wc| 0 – 0.5”wc

Outside Air Damper Airflow Measurement
The third-party controller can use the transducer’s signal from the AMD for the airflow formula to determine the amount of current airflow through the OAD.
FORMULA: CFM = A K (P)M
A = Area
K = K Value
P = Pressure
M = M Value
GreenTrol Airflow Monitoring
The GreenTrol® airflow monitoring station measures airflow using advanced thermal dispersion technology. An integral LCD display provides a local indication of airflow measurement and device configuration. The GreenTrol also accepts up to two airflow probes for averaging.
GreenTrol Airflow Monitor functions:

• LCD readout of measured airflow
• Dual airflow probe averaging

ANALOG OUTPUTS: The airflow monitoring controller has two configurable analog outputs that transmit airflow, temperature, or PID control. They can be configured for one of three analog output ranges: 0-10VDC, 0-5VDC, and 2-10VDC. The controller has been factory configured to use analog output 1 for transmitting outdoor airflow rate
and analog output 2 for outdoor air temperature. The airflow monitoring output is wired to the customer terminal strip for Heat-Cool Only controls. See the technical manual for the airflow controller provided with the unit for instructions on configuring the analog outputs and using the Field Calibration Wizard.
FORMULA: Calculating airflow based on the analog output signal:

Contact Us / More Information

Contact Us
Technical Support and Service
800-789-8550
support@doas.com
Valent Dedicated Outdoor Air Systems
60–28th Avenue North
Minneapolis, MN 55411
Main: 612-877-4800
More Information
Unit Schematics
For configuration and connection questions, see the schematics that shipped with your unit. They can typically be found attached to the main control panel door.

Technical Support
Call: 1-800-789-8550
Email:support@doas.com
OUTDOOR AIR EXPERTS ROBUST DESIGNS DEDICATED SUPPORT
valentair.com
© 2023 Valent
Continuous product improvement is a policy of Valent; therefore, product
functionality and specifications are subject to change without notice. For the
most recent product information visit the product website.
Valent Heat-Cool Controller
Part number: 484755
Rev. 4
January 2023

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