Trane Technologies 4TTR7

This document is an Installer's Guide for Trane Condensing Units, specifically the 4TTR7 series, with the model 4TTR7048B highlighted. It provides comprehensive instructions for the safe and proper installation, start-up, and servicing of these outdoor air conditioning units.

Function Description:

The Trane 4TTR7 series condensing units are outdoor components of a central air conditioning system. Their primary function is to condense refrigerant, releasing heat to the outdoor environment, as part of the refrigeration cycle to provide cooling for indoor spaces. These units are designed to work in conjunction with an indoor evaporator coil and air handler/furnace to create a complete heating, ventilating, and air-conditioning (HVAC) system.

Important Technical Specifications:

Model Covered: 4TTR7048B
Refrigerant Type: R-410A. This refrigerant operates at 50% to 70% higher pressures than R-22, requiring R-410A approved service equipment. It uses POE oil, which is hygroscopic, emphasizing the need to keep the system sealed.
Unit Dimensions (4TTR7048B): 45 inches (H) x 34 inches (D) x 37 inches (W).
Unit Weight (4TTR7048B): Approximately 254 lbs (estimated).
Refrigerant Line Limits:
- Maximum TOTAL length of refrigerant lines (outdoor to indoor unit): 150 feet (including lift).
- Maximum vertical change (lift): 50 feet.
Rated Line Sizes (4TTR7048B): Vapor Line: 7/8 inch, Liquid Line: 3/8 inch.
Service Valve Connection Sizes (4TTR7048B): Vapor Line Connection: 7/8 inch, Liquid Line Connection: 3/8 inch.
Alternate Line Sizes (4TTR7048B): Vapor Line: 3/4 inch, Liquid Line: 3/8 inch.
Low Voltage Wiring:
- 18 AWG: Max. Wire Length 150 Ft.
- 16 AWG: Max. Wire Length 225 Ft.
- 14 AWG: Max. Wire Length 300 Ft.
Factory Charge: The units are factory charged for the outdoor condensing unit, ten (10) feet of tested connecting line, and the smallest rated indoor evaporative coil match. System charge must always be verified via subcooling (TXV/EEV) or superheat (fixed orifice) per the unit nameplate.
Subcooling Charging: The recommended method for charging in cooling mode (above 55°F outdoor temperature) is subcooling. Below 55°F, the weigh-in method is recommended.
Crankcase Heater: If a compressor crankcase heater accessory is used, a one-hour wait is required before starting the unit if the outdoor ambient temperature is below 70°F.
Certifications: AHRI Certified (Unitary Small AC, AHRI Standard 210/240) and UL Listed.

Usage Features:

Installation Flexibility: Can be mounted on a support pad (concrete slab) or rooftop. When on a roof, ensure adequate support and use isolation to prevent sound/vibration transmission.
Clearance Requirements:
- Minimum 5 feet unrestricted discharge area above the unit.
- Minimum 3 feet clearance in front of the control box (access panels) and any other side requiring service.
- Minimum 12 inches from any wall or surrounding shrubbery for adequate airflow.
Cold Climate Considerations:
- Recommended elevation of 3-12 inches above the pad/rooftop to allow drainage of snow/ice and prevent obstruction of drain holes.
- Avoid locations prone to snow drifts; if unavoidable, install a snow drift barrier.
Refrigerant Line Handling:
- The vapor line must always be insulated.
- The liquid line and vapor line must NOT come into direct (metal-to-metal) contact.
- Existing refrigerant lines can be reused if all joints are brazed (not soldered), and lines are correct size, free of leaks, acid, and oil.
- Precautions must be taken to prevent noise from vibration transmission from refrigerant lines within the building structure (e.g., isolation hangers, insulating lines through walls/sills, isolating from ductwork, minimizing 90° turns).
Service Valve Operation: Extreme caution is advised when opening the Liquid Line Service Valve to prevent abrupt release of system charge. The valve stem should only be turned counterclockwise until it just touches the rolled edge (no torque required, approximately five turns). The Gas Service Valve requires a 1/4 turn counterclockwise.
Electrical Connections: Low voltage hook-up diagrams are provided for various indoor unit configurations (TEM 6, TAM 7, Variable Speed UH2/DH2-V Furnace, Variable Speed S-Series Furnace). High voltage power supply must match the equipment nameplate and comply with national, state, and local codes. A separate disconnect switch is required at the outdoor unit. Flexible electrical conduit is recommended for high voltage connections to minimize noise.
System Start-Up: Involves ensuring all installation steps are complete, setting the thermostat to OFF, applying power, waiting one hour if a crankcase heater is used and ambient is below 70°F, then setting the thermostat to ON.
Charge Adjustment: Detailed instructions for subcooling charging (above 55°F outdoor temp) and weigh-in method (below 55°F outdoor temp) are provided, including charts for subcooling corrections and R-410A refrigerant charging.

Maintenance Features:

Leak Check: After brazing refrigerant lines, pressurize to 150 PSIG with dry nitrogen and check for leaks with soapy solution.
Evacuation: Evacuate refrigerant lines and indoor coil until micron gauge reads no higher than 350 microns for one minute.
Drier Installation: For units with a field-installed external drier, ensure correct directional flow and braze it to the liquid line. Always change driers when opening the system for component replacement.
System Stabilization: Allow the system to operate for a minimum of 20 minutes to stabilize before making accurate charge measurements or adjustments.
Post-Installation Checkout: A comprehensive checklist is provided for verifying proper installation and operation, including checking refrigerant lines (leaks, insulation, securing), indoor coil drain, supply registers/return grilles, air filter, electrical connections, outdoor fan operation, and overall system function in each mode.
Troubleshooting Guide: A detailed table of system faults, primary causes, and secondary causes is included for both cooling (C) and heating (H) modes, covering refrigerant circuit and electrical issues.
Safety Warnings: Emphasizes that only qualified personnel should install and service the equipment due to potential hazards (death or serious injury) from improper installation or working with live electrical components. It also highlights the importance of using R-410A approved service equipment and proper handling of R-410A refrigerant and POE oil.