Trane 4TWR6 Heat Pump Installer's Guide

Section 1: Safety

WARNING: This information is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience. Any attempt to repair a central air conditioning product may result in personal injury and/or property damage.

WARNING: These units use R-410A refrigerant, which operates at significantly higher pressures than R-22. Use only R-410A approved service equipment. R-410A systems use POE oil, which readily absorbs moisture. Keep systems sealed whenever possible. If a system has been open to the atmosphere for more than 4 hours, the compressor oil must be replaced. Never break a vacuum with air and always change driers when opening the system for component replacement.

WARNING: LIVE ELECTRICAL COMPONENTS! Extreme caution must be exercised when working with live electrical components during installation, testing, servicing, and troubleshooting. Failure to follow safety precautions could result in death or serious injury.

CAUTION: If using existing refrigerant lines, ensure all joints are brazed, not soldered.

CAUTION: Scroll compressor dome temperatures may be hot. Do not touch the top of the compressor.

Section 2: Unit Location Considerations

2.1 Unit Dimensions and Weight

* Weight values are estimated.

Ensure the roof can support the unit's weight. Properly selected isolation is recommended to reduce sound or vibration transmission. Refer to the application bulletin for detailed mounting information.

Textual Description of Diagram: An illustration shows the dimensions (Height, Depth, Width) of the outdoor unit.

2.2 Refrigerant Piping Limits

1. Maximum refrigerant line length from outdoor to indoor unit should not exceed sixty (60) feet.
2. Maximum vertical change should not exceed twenty-five (25) feet.
3. Service valve connection diameters are shown in Table 5.1.

For line lengths greater than sixty (60) feet, refer to the Refrigerant Piping Application Guide or Software Program.

Textual Description of Diagram: Three diagrams illustrate refrigerant line configurations: a standard line set up to 60 ft, a configuration with a maximum line length of 35 ft and a maximum line lift of 25 ft, and another with a maximum line length of 35 ft and a maximum line lift of 25 ft.

2.3 Suggested Locations for Best Reliability

• Ensure the top discharge area is unrestricted for at least five (5) feet above the unit.
• Provide three (3) feet clearance in front of the control box (access panels) and any side requiring service.
• Do not locate close to bedrooms as operational sounds may be objectionable.
• Avoid locations near windows where condensation and freezing defrost vapor can annoy a customer.
• Position the outdoor unit a minimum of 12 inches from any wall or surrounding shrubbery to ensure adequate airflow.
• Locate the outdoor unit far enough from any structure to prevent excess roof runoff water or icicles from falling directly on the unit.

Textual Description of Diagram: Two diagrams show recommended clearances around the outdoor unit. The first shows a unit placed away from shrubbery and a wall, with minimum clearances for airflow and access. It also indicates to avoid installing near bedrooms. The second diagram emphasizes maintaining a 12-inch clearance from walls and shrubbery, and shows how water or icicles should not fall on the unit.

2.4 Cold Climate Considerations

For areas with snow accumulation and prolonged below freezing temperatures:

• Elevate units 3-12 inches above the pad or rooftop to allow drainage of snow and ice melted during defrost cycles. Ensure drain holes are not obstructed.
• Avoid locations prone to snow drifts. If unavoidable, install a snow drift barrier.

Textual Description of Diagram: An illustration depicts an outdoor unit elevated on snow legs on a pad, with a snow barrier installed to prevent snow buildup. Snowflakes are shown in the background.

2.5 Coastal Considerations

For installations within one mile of salt water, models without factory-supplied Seacoast Salt Shields require the addition of BAYSEAC001 (Seacoast Kit). Refer to Application Guide SS-APB006-EN and Bulletin UN-SVB11A-EN for details.

Section 3: Unit Preparation

3.1 Prepare The Unit For Installation

STEP 1 - Check for shipping damage and report any promptly to the carrier.

Textual Description of Diagram: An illustration shows a unit on a pallet with visible damage, indicated by an 'X' mark.

STEP 2 - Remove the unit from the pallet by cutting the securing tabs.

Textual Description of Diagram: An illustration shows a tool (chisel) and hammer being used to cut securing tabs on the unit's pallet.

Section 4: Setting the Unit

4.1 Pad Installation

When installing on a support pad (e.g., concrete slab):

• The pad should be at least 1 inch larger than the unit on all sides.
• The pad must be separate from any structure.
• The pad must be level.
• The pad should be high enough above grade to allow for drainage.
• The pad location must comply with National, State, and Local codes.

Refer to the application guide for other applications.

Textual Description of Diagram: An illustration shows an outdoor unit being lowered onto a level pad, with a spirit level placed on the pad to indicate its levelness.

Section 5: Refrigerant Line Considerations

5.1 Refrigerant Line and Service Valve Connection Sizes

5.2 Factory Charge

Trane outdoor condensing units are factory charged for the unit, fifteen (15) feet of connecting line, and the smallest indoor coil match. Adjustments are necessary if line length exceeds fifteen (15) feet or a larger indoor coil is used.

5.3 Required Refrigerant Line Length

Determine required line length and lift. Record these values for later use.

Total Line Length: ______ Ft.

Total Vertical Change (lift): ______ Ft.

Textual Description of Diagram: An illustration shows a tape measure being used to measure the length of refrigerant lines between the outdoor unit and the indoor unit (evaporator coil).

5.4 Refrigerant Line Insulation

Important: The Vapor Line must always be insulated. Do not allow the Liquid Line and Vapor Line to come in direct contact.

CAUTION: If using existing refrigerant lines, ensure all joints are brazed, not soldered.

For retrofit applications, ensure indoor coils and lines are the correct size and free of leaks, acid, and oil. Refer to publications SS-APG006-EN and APP-APG011-EN for more information.

Textual Description of Diagram: A diagram shows cross-sections of refrigerant lines, illustrating the vapor line (larger) and liquid line (smaller). The vapor line is shown with insulation. A crossed-out diagram shows the liquid and vapor lines in direct contact, indicating this is not allowed.

Section 6: Refrigerant Line Routing

6.1 Precautions

Take precautions to prevent noise transmission from refrigerant lines to the building structure. Comply with codes when isolating line sets from structural elements.

• Use isolation-type hangers when fastening lines to joists or framing.
• Use isolation hangers in stud spaces or enclosed ceilings.
• Insulate and isolate lines running through walls or sills.
• Isolate lines from all ductwork.
• Minimize the number of 90° turns.

Textual Description of Diagram: Two diagrams illustrate proper refrigerant line routing and isolation. The first shows lines routed through a wall with insulation and sealant. The second shows lines suspended from joists using isolators every 8 feet, with the liquid line secured to the vapor line. A crossed-out diagram shows lines hanging directly from ductwork, indicating this is prohibited.

Section 7: Refrigerant Line Brazing

7.1 Braze The Refrigerant Lines

STEP 1 - Remove caps/plugs. Deburr and clean pipe ends with an emery cloth.

Textual Description of Diagram: An illustration shows the end of a refrigerant line with a cap being removed, and a deburring tool being used on the pipe end.

STEP 2 - Remove pressure tap cap and valve cores from both service valves.

Textual Description of Diagram: An illustration shows a service valve with its pressure tap cap removed, and a valve core being unscrewed using a tool.

STEP 3 - Purge the refrigerant lines and indoor coil with dry nitrogen.

Textual Description of Diagram: An illustration shows refrigerant lines connected to a service valve, with a nitrogen line connected for purging.

STEP 4 - Wrap a wet rag around the valve body to prevent heat damage. Continue the dry nitrogen purge. Braze the refrigerant lines to the service valves. Continue purging. Remove the wet rag only after brazing is complete.

Important: Remove the wet rag before stopping the dry nitrogen purge.

NOTE: Take precautions to avoid heat damage to the basepan during brazing. Keep the flame directly off the basepan.

Textual Description of Diagram: An illustration shows a wet rag wrapped around a service valve during brazing, with nitrogen purging occurring. Another illustration shows the brazing process at the service valve connection.

STEP 5 - Replace the pressure tap valve cores after the service valves have cooled.

Textual Description of Diagram: An illustration shows a valve core being screwed back into the pressure tap port of a service valve.

Section 8: Refrigerant Line Leak Check

8.1 Check For Leaks

STEP 1 - Pressurize the refrigerant lines and evaporator coil to 150 PSIG using dry nitrogen.

Textual Description of Diagram: An illustration shows a pressure gauge connected to the refrigerant lines, indicating 150 PSIG.

STEP 2 - Check for leaks using a soapy solution or bubbles at each brazed location. Remove nitrogen pressure and repair any leaks before continuing.

Textual Description of Diagram: An illustration shows bubbles forming on a brazed joint, indicating a leak.

Section 9: Evacuation

9.1 Evacuate the Refrigerant Lines and Indoor Coil

Important: Do not open the service valves until leak check and evacuation are complete.

STEP 1 - Evacuate until the micron gauge reads no higher than 350 microns, then close the valve to the vacuum pump.

Textual Description of Diagram: An illustration shows a micron gauge connected to the system, displaying a reading of 350 microns.

STEP 2 - Observe the micron gauge. Evacuation is complete if the micron gauge does not rise above 500 microns in one (1) minute. Blank off the vacuum pump and micron gauge, and close the valves on the manifold gauge set.

Textual Description of Diagram: An illustration shows a timer indicating '1 MIN.' and a micron gauge, implying a waiting period to check for pressure rise.

Section 10: Service Valves

10.1 Open the Gas Service Valve

Important: Leak check and evacuation must be completed before opening service valves. Do not vent refrigerant gases into the atmosphere.

STEP 1 - Remove valve stem cap.

STEP 2 - Using an adjustable wrench, turn the valve stem 1/4 turn counterclockwise to the fully open position.

STEP 3 - Replace the valve stem cap. Tighten finger tight plus an additional 1/6 turn.

Textual Description of Diagram: An illustration shows a service valve with its cap removed, a 3/16" hex wrench being used to turn the valve stem counterclockwise to the fully open position, and the cap being replaced.

10.2 Open the Liquid Line Service Valve

WARNING: Extreme caution should be exercised when opening the Liquid Line Service Valve. Turn counterclockwise until the valve stem just touches the rolled edge. No torque is required. Failure to follow this warning will result in abrupt release of system charge and may result in personal injury and/or property damage.

Important: Leak check and evacuation must be completed before opening the service valves.

STEP 1 - Remove service valve cap.

STEP 2 - Fully insert a 3/16" hex wrench into the stem and back out counterclockwise until the valve stem just touches the rolled edge (approximately five (5) turns).

STEP 3 - Replace the valve cap. Tighten finger tight plus an additional 1/6 turn.

Textual Description of Diagram: An illustration shows the liquid line service valve, with a 3/16" hex wrench inserted into the stem and turned counterclockwise until the stem touches the rolled edge. The cap is then replaced.

Section 11: Electrical - Low Voltage

11.1 Low Voltage Maximum Wire Length

Variable Speed Air Handler Hook-up Diagram

Textual Description of Diagram: A wiring diagram illustrates the low-voltage connections between a comfort control thermostat, a variable speed air handler, and a heat pump. It shows the wire color coding and terminal connections for each component.

Communicating Indoor Unit with 24 V Control Hook-up Diagram

Textual Description of Diagram: A wiring diagram shows connections for a communicating indoor unit with a 24V control system, linking a comfort control thermostat to a variable speed air handler and a heat pump.

Notes:

1. If electric heat lacks a 3rd contactor (CH), connect a jumper from W3 to W2. If it lacks a 2nd contactor (BH), connect a jumper from W2 to W1.
2. Installer must remove the factory-installed jumper between R and BK on the air handler terminal strip.
3. Installer must add a field-installed jumper between R and O on the air handler terminal strip.
4. 4TWR6 units require 80% airflow with Y1 (low stage) and 100% airflow with Y2 (high stage).
5. Connect Y1 from comfort control to Y at the VS air handler and Y1 (yellow) at the HP.
6. Connect Y2 from comfort control to BK at the VS air handler and Y2 (yellow/red) at the HP.

Air Conditioner or Heat Pump Wiring

Textual Description of Diagram: A diagram shows the wiring connections from a comfort control thermostat to a variable speed air handler and an outdoor heat pump unit, with wires neatly bundled behind the service valve cover.

Comfort Control Wiring

Textual Description of Diagram: A close-up view of a comfort control thermostat's wiring terminals, showing connections for Red, Yellow, Brown, Green, White, Blue, and Orange wires.

Notes:

1. Refer to the User Interface setup menu for 24 VAC control mode and cooling CFM options.
2. First stage CFM options for 4TWR6 are 65-80%.
3. For furnace+heat pump applications, the comfort control must be dual fuel capable or use accessory TAYPLUS103A.
4. The W3 terminal may not be present on the indoor unit.

Variable Speed Furnace Hook-up Diagram

Textual Description of Diagram: A wiring diagram illustrates connections between a comfort control thermostat, a variable speed furnace, and a heat pump. It details jumper configurations and terminal connections.

Notes:

1. Comfort control must be dual fuel capable or use accessory TAYPLUS103A.
2. Installer must cut the factory R to BK jumper on the furnace circuit board or set the S5-2 DIP switch to OFF (for new 15-digit models).
3. Installer must add a field-installed jumper between R and O on the furnace terminal strip.
4. 4TWR6 units require 80% airflow with Y1 (low stage) and 100% airflow with Y2 (high stage).
5. Connect Y1 from comfort control to Y at the VS furnace and Y1 (yellow) at the HP.
6. Connect Y2 from comfort control to BK at the VS furnace and Y2 (yellow/red) at the HP.
7. Comfort control may not have W2 or W3 terminals.
8. If a single-stage heating comfort control is used, jumper W1 to W2 on the furnace terminal strip.

*AM7 Air Handler Hook-up Diagram

Textual Description of Diagram: A wiring diagram shows the connections for an AM7 Air Handler, linking a comfort control thermostat to the air handler and the outdoor heat pump unit. It details specific terminal connections and wire colors.

*AM7 Air Handler Hook-up (Continued)

Textual Description of Diagram: Continuation of the AM7 Air Handler hook-up diagram, showing further wiring details and connections.

11.3 Defrost Control

Defrost controls have a selectable termination temperature. As shipped, defrost terminates at 47°F. For a higher termination temperature (70°F), cut Jumper J2. This applies when the ambient temperature is at or below 30°F.

Pin Identification:

1. TEST_COMMON: Shorting other pins to this pin executes their function. Leaving open results in normal operation.
2. TST = Test: Shorting TEST_COMMON to this pin speeds up defrost board timings.
3. FRC_DFT = Forced Defrost: Short TEST_COMMON to this pin for two (2) seconds to initiate a forced defrost.

Defrost Control Checkout

Normal operation requires:

• LED on board flashing 1 time/second.
• 24 V AC between R & B.
• 24 V AC between Y & B with unit operating.
• Defrost initiation when FRC_DFT pin is shorted to TEST_COMMON pin.

Refer to control box service information if a defrost control problem is suspected.

Textual Description of Diagram: A diagram shows a defrost control board with labeled pins (J1, J2, J3, FRC_DFT, TST, LOW_FAN, TEST_COMMON) and jumper positions. It also indicates DIP switch settings for AC/Heat Pump and CFM/Ton configurations.

Section 12: Electrical - High Voltage

12.1 High Voltage Power Supply

WARNING: LIVE ELECTRICAL COMPONENTS! Extreme caution must be exercised when working with live electrical components during installation, testing, servicing, and troubleshooting. Failure to follow safety precautions could result in death or serious injury.

High voltage power supply must match the equipment nameplate. Power wiring must comply with national, state, and local codes. Follow instructions on the unit wiring diagram located inside the control box cover and in the Service Facts document.

Textual Description of Diagram: An illustration shows the outdoor unit with an arrow pointing to the location of the unit's nameplate, which contains electrical specifications.

12.2 High Voltage Disconnect Switch

Install a separate disconnect switch at the outdoor unit. Flexible electrical conduit is recommended for high voltage connections where vibration transmission may cause noise.

Textual Description of Diagram: An illustration shows the outdoor unit connected to a disconnect switch via electrical conduit.

12.3 High Voltage Ground

Ground the outdoor unit per national, state, and local code requirements.

Section 13: Start Up

13.1 System Start Up

STEP 1 - Ensure Sections 7 through 12 have been completed.

STEP 2 - Set System Thermostat to OFF.

Textual Description of Diagram: An illustration shows a thermostat display set to 'OFF'.

STEP 3 - Turn on disconnect(s) to apply power to the indoor and outdoor units.

Textual Description of Diagram: An illustration shows a disconnect switch in the 'ON' position.

STEP 4 - Wait one (1) hour before starting the unit if a compressor crankcase heater is used and the outdoor ambient temperature is below 70°F.

Textual Description of Diagram: An octagonal graphic displays '60 MIN.', indicating a waiting period.

STEP 5 - Set system thermostat to ON.

Textual Description of Diagram: An illustration shows a thermostat display set to 'ON'.

Section 14: System Charge Adjustment

14.1 Temperature Measurements

STEP 1 - Check the outdoor temperatures. Subcooling (in cooling mode) is the recommended method for charging above 55°F ambient. For outdoor temperatures below 55°F, follow Superheat charging instructions (in heating mode).

Note: It is important to return in the spring or summer to accurately charge the system in cooling mode with outdoor ambient temperature above 55°F.

For best results, the indoor temperature should be kept between 70°F to 80°F.

Textual Description of Diagram: Three thermometer icons are shown, labeled 'Outdoor Temp 1', 'Outdoor Temp 2', and 'Indoor Temp', with checkmarks and crosses indicating temperature ranges for different procedures.

14.2 Subcooling Charging in Cooling (Above 55° F Outdoor Temp.)

STEP 1 - Use the refrigerant line total length and lift measurements from Section 5.3.

Total Line Length: ______ Ft.

Vertical Change (Lift): ______ Ft.

Textual Description of Diagram: An illustration shows the outdoor unit and indoor unit with arrows indicating 'LIFT' and 'LINE LENGTH' measurements.

STEP 2 - Determine the final subcooling value using the total line length and lift measurements and the provided charts.

Textual Description of Diagram: Charts are presented for 2 Ton, 4 Ton, and 5 Ton units, showing 'REFRIGERANT LINE LIFT (FT)' on the Y-axis and 'TOTAL REFRIGERANT LINE LENGTH (FT)' on the X-axis. Different zones indicate 'Add 1°', 'Add 2°', 'Add 3°', 'Add 4°', and 'Use design subcooling' based on line length and lift.

STEP 4 - Measure the liquid line temperature and pressure at the outdoor unit's service valve.

Measured Liquid Line Temp: ______ °F

Liquid Gage Pressure: ______ PSI

Final Subcooling Value: ______ °F

Textual Description of Diagram: An illustration shows a manifold gauge set connected to the outdoor unit's service valves, with a temperature probe attached to the liquid line. A digital thermometer displays a temperature reading.

STEP 5 - Use the final subcooling value, refrigerant temperature, and pressure from STEP 4 to determine the proper liquid gage pressure using Table 14.2.

Table 14.2: R-410A REFRIGERANT CHARGING CHART

STEP 6 - Adjust refrigerant level to attain proper gage pressure. Add refrigerant if the Liquid Gage Pressure is lower than the chart value. Recover refrigerant if higher. Stop adding/recovering when the liquid line temperature and Liquid Gage Pressure match the charging chart Final Subcooling value.

Textual Description of Diagram: An illustration shows a refrigerant tank connected to the manifold gauge set, with arrows indicating the direction of refrigerant flow for adding or recovering.

STEP 7 - Stabilize the system. Wait 20 minutes for conditions to stabilize between adjustments. Remove gages and replace service port caps.

Textual Description of Diagram: An octagonal graphic displays '20 MIN.', indicating a waiting period for system stabilization.

STEP 8 - Verify typical performance by referring to System Pressure Curves in the Service Facts.

Textual Description of Diagram: Performance curves are shown for cooling and heating modes, plotting discharge and suction pressure against outdoor temperature for different indoor conditions.

STEP 9 - Record System Information for reference.

Outdoor model number: ______ Measured Suction Line Temp: ______ °F

Measured Outdoor Ambient: ______ °F

Measured Indoor Ambient: ______ °F

Liquid Gage Pressure: ______ PSI

Measurement Liquid Line Temp: ______ °F

14.3 Subcooling Charging Below 55° F Outdoor Temp. (In Heating Only)

STEP 1 - Check the outdoor temperature. If ODT is less than 55°F, follow these instructions for heating mode. For temperatures above 55°F, see Section 14.2.

Note: It is important to return in the spring or summer to accurately charge the system in cooling mode with outdoor ambient above 55°F.

For best results, indoor temperature should be between 70°F and 80°F. Add system heat if needed.

Textual Description of Diagram: Thermometer icons labeled 'Outdoor Temp' and 'Indoor Temp' are shown, with checkmarks and crosses indicating temperature ranges.

STEP 2 - Stabilize the system by operating in heating mode for a minimum of 20 minutes.

Important: Whenever charge is added or removed, the system must run for a minimum of 20 minutes before accurate measurements can be made.

Textual Description of Diagram: An octagonal graphic displays '20 MIN.', indicating a waiting period for system stabilization.

STEP 3 - Measure the suction line pressure and temperature at the "true" suction line. Compare these values to the 15 degree superheat chart in Table 14.3.

Measured Suction Line Temperature: ______ °F

Measured Suction Line Pressure: ______ °F

Textual Description of Diagram: An illustration shows a manifold gauge set and temperature probe attached to the suction line of the outdoor unit, with a digital thermometer displaying a temperature reading.

STEP 4 - Use the measured values to determine a target superheat of 15 degrees. Adjust refrigerant level to attain 15 degrees of superheat. Add refrigerant if suction line temperature is above the value in line with the measured suction gage pressure. Recover refrigerant if lower.

Table 14.3: 15 degree Superheat Chart

STEP 5 - Adjust refrigerant level to attain 15 degrees of superheat. Add refrigerant if the suction line temperature is above the value that is in line with the measured suction gage pressure. Recover refrigerant if the suction line temperature is lower.

STEP 6 - Stabilization and completion. Wait 20 minutes for the system condition to stabilize between adjustments. Remove gages and replace service port caps.

Textual Description of Diagram: An octagonal graphic displays '20 MIN.', indicating a waiting period for system stabilization.

STEP 7 - Target 10-15 degrees of subcooling using Section 14.2 as a guide. It is important to return in the spring or summer to accurately charge the system in cooling mode with outdoor ambient above 55°F.

STEP 8 - Verify typical performance. Refer to System Pressure Curves in the Service Facts to verify typical performance.

Textual Description of Diagram: Performance curves are shown for cooling and heating modes, plotting discharge and suction pressure against outdoor temperature for different indoor conditions.

Section 15: Checkout Procedures and Troubleshooting

15.1 Operational And Checkout Procedures

Final phases of this installation are the unit Operational and Checkout Procedures. To obtain proper performance, all units must be operated and charge adjustments made.

Important: Perform a final unit inspection to ensure factory tubing has not shifted during shipment. Adjust tubing if necessary so tubes do not rub against each other when the unit runs. Also, ensure wiring connections are tight and properly secured.

CHECKOUT PROCEDURE

After installation is complete, check the entire system against the following list:

• Leak check refrigerant lines. [✔️]
• Properly insulate suction lines and fittings. [✔️]
• Properly secure and isolate all refrigerant lines. [✔️]
• Seal passages through masonry. If mortar is used, prevent mortar from coming into direct contact with copper tubing. [✔️]
• Verify that all electrical connections are tight. [✔️]
• Observe outdoor fan during on cycle for clearance and smooth operation. [✔️]
• Ensure that indoor coil drain line drains freely. Pour water into drain pan. [✔️]
• Ensure that supply registers and return grilles are open and unobstructed. [✔️]
• Ensure that a return air filter is installed. [✔️]
• Ensure that the correct airflow setting is used (Indoor blower motor). [✔️]
• Operate complete system in each mode to ensure safe operation. [✔️]

15.2 Troubleshooting

Textual Description of Diagram: A table lists various system faults categorized under 'REFRIGERANT CIRCUIT' and 'ELECTRICAL', with columns indicating Primary (P) and Secondary (S) causes for Cooling (C) and Heating (H) modes. It also includes specific issues like 'Defrost Control Defective' and 'Coil Leaking'.

Textual Description of Diagram: A table lists system faults related to 'DEFROST' such as 'Unit Won't Initiate Defrost', 'Defrost Terminates on Time', and 'Unit Icing Up', with corresponding causes.