Trane Technologies TTA156 Head Pressure Control Kit Installation Guide

Trane Technologies TTA156 Head Pressure Control Kit

Product Specifications

• Product Name: Head Pressure Control Kit
• Model: OdysseyTM Split System with SymbioTM Controls
• Capacity: 13 to 25 Tons
• Compatible Models: BAYLOAMS20: TTA156/180/201/240/251/300, TWA156/180/201/240
• Voltage: 120-600VAC
• Manufacturer Part Number: X13651682
• Pressure Range: 35 psig to 435 psig

Product Usage Instructions

Installation

1. Only qualified personnel should install and service the equipment.
2. Ensure proper field wiring and grounding as described in the manual to prevent hazards.

Operation:

1. Read the manual thoroughly before operating the unit.
2. Use proper Personal Protective Equipment (PPE) as described in the manual.

Maintenance

1. Follow the recommended maintenance schedule provided in the manual.
2. Contact your local representative for specific handling concerns with R-454B refrigerant.

Frequently Asked Questions

Q: Who should install the equipment?

A: Only qualified personnel should install and service the equipment to prevent any hazards.

Q: What refrigerant does the equipment use?

A: The equipment described in this manual uses R-454B refrigerant, which is flammable (A2L). Use ONLY R454B rated service equipment and components.

Q: What precautions should be taken during installation?

A: Ensure proper field wiring and grounding as described in the manual to avoid fire and electrocution hazards.

SAFETY WARNING
Only qualified personnel should install and service the equipment. The installation, starting up, and servicing of heating, ventilating, and air- conditioning equipment can be hazardous and requires specific knowledge and training. Improperly installed, adjusted or altered equipment by an unqualified person could result in death or serious injury. When working on the equipment, observe all precautions in the literature and on the tags, stickers, and labels that are attached to the equipment.

Introduction

Read this manual thoroughly before operating or servicing this unit.

Warnings, Cautions, and Notices
Safety advisories appear throughout this manual as required. Your personal safety and the proper operation of this machine depend upon the strict observance of these precautions.

The three types of advisories are defined as follows

• WARNING
  Indicates a potentially hazardous situation which, if not avoided, could result in death or serious injury.

• CAUTION
  Indicates a potentially hazardous situation which, if not avoided, could result in minor or moderate injury. It could also be used to alert against unsafe practices.

• NOTICE
  Indicates a situation that could result in equipment or property-damage only accidents.

Important Environmental Concerns
Scientific research has shown that certain man-made chemicals can affect the earth’s naturally occurring stratospheric ozone layer when released to the atmosphere. In particular, several of the identified chemicals that may affect the ozone layer are refrigerants that contain Chlorine, Fluorine and Carbon (CFCs) and those containing Hydrogen, Chlorine, Fluorine and Carbon (HCFCs). Not all refrigerants containing these compounds have the same potential impact to the environment. Trane advocates the responsible handling of all refrigerants.

Important Responsible Refrigerant Practices
Trane believes that responsible refrigerant practices are important to the environment, our customers, and the air conditioning industry. All technicians who handle refrigerants must be certified according to local rules. For the USA, the Federal Clean Air Act (Section 608) sets forth the requirements for handling, reclaiming, recovering and recycling of certain refrigerants and the equipment that is used in these service procedures. In addition, some states or municipalities may have additional requirements that must also be adhered to for responsible management of refrigerants. Know the applicable laws and follow them.

WARNING
Proper Field Wiring and Grounding Required!
Failure to follow code could result in death or serious injury.
All field wiring MUST be performed by qualified personnel. Improperly installed and grounded field wiring poses FIRE and ELECTROCUTION hazards. To avoid these hazards, you MUST follow requirements for field wiring installation and grounding as described in NEC and your local/state/national electrical codes.

WARNING
Personal Protective Equipment (PPE) Required!
Failure to wear proper PPE for the job being undertaken could result in death or serious injury. Technicians, in order to protect themselves from potential electrical, mechanical, and chemical hazards, MUST follow precautions in this manual and on the tags, stickers, and labels, as well as the instructions below:

• Before installing/servicing this unit, technicians MUST put on all PPE required for the work being undertaken (Examples; cut resistant gloves/sleeves, butyl gloves, safety glasses, hard hat/bump cap, fall protection, electrical PPE and arc flash clothing). ALWAYS refer to appropriate Safety Data Sheets (SDS) and OSHA guidelines for proper PPE.
• When working with or around hazardous chemicals, ALWAYS refer to the appropriate SDS and OSHA/GHS (Global Harmonized System of Classification and Labelling of Chemicals) guidelines for information on allowable personal exposure levels, proper respiratory protection and handling instructions.
• If there is a risk of energized electrical contact, arc, or flash, technicians MUST put on all PPE in accordance with OSHA, NFPA 70E, or other country-specific requirements for arc flash protection, PRIOR to servicing the unit. NEVER PERFORM ANY SWITCHING, DISCONNECTING, OR VOLTAGE TESTING WITHOUT PROPER ELECTRICAL PPE AND ARC FLASH CLOTHING. ENSURE ELECTRICAL METERS AND EQUIPMENT ARE PROPERLY RATED FOR INTENDED VOLTAGE.

WARNING
Follow EHS Policies!
Failure to follow instructions below could result in death or serious injury.

• All Trane personnel must follow the company’s Environmental, Health and Safety (EHS) policies when performing work such as hot work, electrical, fall protection, lockout/tagout, refrigerant handling, etc. Where local regulations are more stringent than these policies, those regulations supersede these policies.
• Non-Trane personnel should always follow local regulations.

WARNING
R-454B Flammable A2L Refrigerant!
Failure to use proper equipment or components as described below could result in equipment failure, and possibly fire, which could result in death, serious injury, or equipment damage.
The equipment described in this manual uses R-454B refrigerant which is flammable (A2L). Use ONLY R-454B rated service equipment and components. For specific handling concerns with R-454B, contact your local representative.

Copyright
This document and the information in it are the property of Trane, and may not be used or reproduced in whole or in part without written permission. Trane reserves the right to revise this publication at any time, and to make changes to its content without obligation to notify any person of such revision or change.

Trademarks
All trademarks referenced in this document are the trademarks of their respective owners.

Revision History
Updates throughout the document to includes the R454–B refrigerant.

Pre-Installation

Parts List

General Information

Table 1. Low ambient controller specifications

Disable Evaporator Defrost Control

Important: For proper operation of the low ambient head pressure control accessory in an Odyssey condenser, the Evaporator Defrost Control (EDC) function MUST be disabled.
To disable the EDC, navigate to the “Utilities” menu on the Symbio™ 700 user interface and change the configuration parameter “Evaporator Defrost Control” to “Disabled”. The Symbio Service and Installation mobile application can also be used to edit this parameter.

Installation

Controller

WARNING
Hazardous Voltage w/Capacitors!
Failure to disconnect power and discharge capacitors before servicing could result in death or serious injury.
Disconnect all electric power, including remote disconnects and discharge all motor start/run capacitors before servicing. Follow proper lockout/tagout procedures to ensure the power cannot be inadvertently energized. For variable frequency drives or other energy storing components provided by Trane or others, refer to the appropriate manufacturer’s literature for allowable waiting periods for discharge of capacitors. Verify with a CAT III or IV voltmeter rated per NFPA 70E that all capacitors have discharged.

WARNING
Proper Field Wiring and Grounding
Required!
Failure to follow code could result in death or serious injury.
All field wiring MUST be performed by qualified personnel. Improperly installed and grounded field wiring poses FIRE and ELECTROCUTION hazards. To avoid these hazards, you MUST follow requirements for field wiring installation and grounding as described in NEC and your local/state/national electrical codes.

1. Prepare the unit for installation.
   • Disconnect and lock out all power from the unit.
   • Remove the compressor and control box access panel(s), see Figure 2, p. 7.
2. Remove the Plug screws and install the two brackets with edge protection as shown in Figure 3, p. 8 and Figure 5, p. 8.
3. Mount one controller on each bracket using two 8-32 x 1.25 screws provided. Refer to Figure 4, p. 8.

Transducer and Tee

WARNING
R-410A Refrigerant under Higher
Pressure than R-22!
Failure to use proper equipment or components as described below, could result in equipment failing and possibly exploding, which could result in death, serious injury, or equipment damage.
The units described in this manual use R-410A refrigerant which operates at higher pressures than R-22. Use ONLY R-410A rated service equipment or components with these units. For specific handling concerns with R-410A, please contact your local Trane representative.

WARNING
R-454B Flammable A2L Refrigerant!
Failure to use proper equipment or components as described below could result in equipment failure, and possibly fire, which could result in death, serious injury, or equipment damage.
The equipment described in this manual uses R-454B refrigerant which is flammable (A2L). Use ONLY R-454B rated service equipment and components. For specific handling concerns with R-454B, contact your local representative.

WARNING
Risk of Fire — Flammable Refrigerant!
Failure to follow instructions below could result in death or serious injury, and equipment damage.

• To be repaired only by trained service personnel.
• Do not puncture refrigerant tubing.
• Dispose of properly in accordance with federal or local regulations.

NOTICE
Wire Damage!
Failure to follow instructions below could result in damaged wires.
Use provided wire ties to make sure wire are secured and protected from sharp edges and hot surfaces.

Install a tee and pressure transducer on the discharge line service port at each compressor using the following instructions:

1. Remove red tags (applicable only for R–454B units)

2. Install the transducer onto the Tee port without the valve core.

3. Place the Tee flare nut with valve core depressor on the unit high pressure tap, where the cap nut was located.
   Note: If the high pressure service port is on another
   Tee, refer to Figure 8, p. 9 for connection.

4. For R-454B units, install the red tag in the new service port location before installing the cap nut.

5. Tighten flare nut securely to the high pressure service port and check for leaks.

Wiring

NOTICE
Wire Damage!
Failure to follow instructions below could result in damaged wires.
Use provided wire ties to make sure wire are secured and protected from sharp edges and hot surfaces.

Control Box Wiring

WARNING
Hazardous Voltage w/Capacitors!
Failure to disconnect power and discharge capacitors before servicing could result in death or serious injury.
Disconnect all electric power, including remote disconnects and discharge all motor start/run capacitors before servicing. Follow proper lockout/tagout procedures to ensure the power cannot be inadvertently energized. For variable frequency drives or other energy storing components provided by Trane or others, refer to the appropriate manufacturer’s literature for allowable waiting periods for discharge of capacitors. Verify with a CAT III or IV voltmeter rated per NFPA 70E that all capacitors have discharged.

WARNING
Proper Field Wiring and Grounding Required!
Failure to follow code could result in death or serious injury.
All field wiring MUST be performed by qualified personnel. Improperly installed and grounded field wiring poses FIRE and ELECTROCUTION hazards. To avoid these hazards, you MUST follow requirements for field wiring installation and grounding as described in NEC and your local/state/national electrical codes.

1. Ensure Unit power has been disconnected and locked out.

2. Disconnect both fan motor harnesses from contactors, install 14 gauge wire harnesses (supplied in kit) between the controller, fan contactors and outdoor fan motor harnesses for both refrigeration circuits. See Figure 9, p. 11.

3. FOR HEAT PUMP UNITS ONLY, connect Switchover valve 1 (SOV1) harness (supplied in kit) using the following steps:

   • Disconnect black wire from SOV1. See Figure 10, p. 12.
   • Reconnect black wire to black wire in kit harness by making an in-line connection. Securely attach this in-line connection to adjacent wiring with wire ties. See Figure 11, p. 12.
   • Connect terminal with black and orange wires to the open tab on SOV1. See Figure 11, p. 12.
   • Connect orange wire with stripped end to Rev valve terminal on low amb controller 1. See Figure 11, p. 12.

4. FOR HEAT PUMP UNITS ONLY, connect Switchover valve 2 (SOV2) harness (supplied in kit) using the following steps:

   • Disconnect blue wire from SOV2. See Figure 10, p. 12.
   • Reconnect blue wire to black wire in kit harness by making an in-line connection. Securely attach this in-line connection to adjacent wiring with wire ties. See Figure 11, p. 12.
   • Connect terminal with black and orange wires to the open tab on SOV2. See Figure 11, p. 12.
   • Connect orange wire with strip end to Rev valve terminal on low amb controller 2. See Figure 11, p. 12.

5. Install jumper harness (supplied in kit) between the two controllers. See diagram for reference. See Figure 12,
   p. 13.

6. Install 24VAC harness (supplied in kit) between unit controller (UC-P5) and the Low Ambient Controller1. See Figure 13, p. 13.

7. For each refrigeration circuit install transducer wires to controller as per kit diagram. See Figure 14, p. 14.

8. For each refrigeration circuit install the thermistors on the outdoor air sensor bracket and connect on controller as per kit diagram. See Figure 15, p. 15.

9. Finish wiring installation.

   • Using wire ties, bundle and dress any excess wires away from sharp edges, moving parts, or hot tubes.
   • Apply the diagram (supplied in kit) to an open area on the low voltage access panel. See Figure 2, p. 7 for proper replacement.
   • After the settings have been properly adjusted (see ““Controller Settings,” p. 15), reinstall the compressor and control box access panels and secure with screws that were removed.

Controller Settings
Jumper Position for TTA Models (Cooling Only)
For non-heat pump applications, the heat pump select jumper must be in the Default (N.O.) position, and the HP terminals must be left unconnected. Refer to Figure 16, p. 15.

Jumper Position for TWA Models (Heat Pump)
For heat pump applications, the heat pump select jumper must be in the (N.C.) position, see Figure 17, p. 15.

Operation
The low ambient controller is used to maintain head pressure within an acceptable range when ambient temperature falls below 50 °F. It reads discharge pressure from the refrigeration circuit and “cycles” the outdoor fan motor on and off to maintain the desired discharge pressure at the selected setpoint anytime the compressor is operating.

Set Pressure Setpoint
The pressure setpoint should be adjusted to 250 psig for R-410A refrigerant and 230 psig for R-454B refrigerant. When the ambient temperature is above 50°F (10°C), the outdoor fan motor will be energized continuously. When the ambient temperature is below 50°F, the pressure sensor reading is used to switch the motor on or off. When the pressure is 15psi below the set pressure the motor will be turned off. When the pressure is 15psi above the set pressure, the motor will be turned on.
After completion of installation and pressure setting adjustment), reinstall the compressor and control box access panels and secure with screws that were removed.
Reconnect all power to the unit. Refer to troubleshooting guide, if needed.

Operation and Troubleshooting

Checkout Procedure

WARNING
Hazardous Service Procedures!
Failure to follow all precautions in this manual and on the tags, stickers, and labels could result in death or serious injury.
Technicians, in order to protect themselves from potential electrical, mechanical, and chemical hazards, MUST follow precautions in this manual and on the tags, stickers, and labels, as well as the following instructions: Unless specified otherwise, disconnect all electrical power including remote disconnect and discharge all energy storing devices such as capacitors before servicing. Follow proper lockout/tagout procedures to ensure the power can not be inadvertently energized. When necessary to work with live electrical components, have a qualified licensed electrician or other individual who has been trained in handling live electrical components perform these tasks.
Before leaving the installation, observe for correct operation through the desired pressure range (see Table 3, p. 18).

Table 2. Troubleshooting guide

No fan operation

| No 24 volt control voltage| Check for 24 Vac between Y1 or Y2 and C terminals – it should read 24 volts.

No line voltage

| Check voltage across brown, orange, and yellow motor leads. If no voltage is present verify all wiring is correct.

Bad fan motor or controller

| If fan does not start, motor is bad and should be replaced. If motor does start, check controller settings. If motor still fails to start, replace controller.

Improper fan operation

| Heat pump jumper not configured correctly| ****

Verify the heat pump jumper is configured correctly.

Control is not wired correctly| See wiring diagrams. Ensure that the 24 Vac power supply is connected.

No fan modulation

| ****

No need to modulate the fan

| If pressure is equal to or greater than the head pressure control setpoint, the fan will be operating at full speed.

No input pressure to control

| Check for proper transducer and Tee installation. Schrader valve depressor must depress Schrader valve enough to allow refrigerant into pressure transducer.
Heat pump inputs wired incorrectly into the controller| ****

Check diagram and verify heat pump inputs are properly wired into the controller.

Miswired| Check that the 24 Vac signal and the transducer are wired up correctly into the controller.

Erratic fan operation

| Control is not wired correctly| See wiring diagrams.

Pressure transducer problem

| Check for proper transducer and Tee installation. Schrader valve depressor must depress Schrader valve enough to allow refrigerant into pressure transducer.
Dirty or blocked condenser coil| Clean condenser coil.
The high pressure switch trips off| Improper head pressure setpoint setting| See unit fails to start above.
Check the setpoint and reduce it if needed.
Reduced cooling capacity at low Ambient| Evaporative Defrost Control is active| Disable EDC function in Symbio™ 700

Table 3. Pressure vs. voltage

Trane and American Standard create comfortable, energy-efficient indoor environments for commercial and residential applications. For more information, please visit trane.com or americanstandardair.com.

Trane and American Standard have a policy of continuous product and product data improvement and reserve the right to change design and specifications without notice. We are committed to using environmentally conscious print practices.

ACC-SVN190C-EN 11 Aug 2024 Supersedes ACC-SVN190B-EN (August 2021)

©2024

References

• American Standard® | Air Conditioning and Heating | HVAC Systems
• Trane Heating & Air Conditioning

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