Trane TCAA Series - User Manual

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Overview

Function Description
Important Technical Specifications
Usage Features
Maintenance Features
Inspection Methods
Winter Shutdown Preparation
Safety Warnings
Warranty

The Trane Packaged Air-Cooled Magnetic Bearing Chiller, Model TCAA, is designed for installation, operation, and maintenance in commercial and residential applications. This manual provides essential information for qualified personnel to properly operate, maintain, and troubleshoot the unit.

Function Description

The TCAA chiller is a packaged air-cooled unit that utilizes flooded shell and tube evaporators and condensers. It is designed to provide cooling by employing a refrigeration cycle that involves two-stage oil-free variable speed centrifugal magnetic bearing compressors. The magnetic bearings eliminate the need for lubricating oil, reducing energy losses due to friction and increasing heat transfer efficiency. A variable speed drive on the motor allows the compressor to operate efficiently at partial loads. Refrigerant is metered through an electronic expansion valve that maximizes chiller efficiency at part load. Microprocessor-based unit controls provide accurate chilled water control, monitoring, protection, and adaptive limit functions, preventing the chiller from operating outside its limits or compensating for unusual operating conditions.

Important Technical Specifications

The TCAA chillers are available in capacities ranging from 110 to 450 tons. They feature 225 PSI operating pressure for the evaporator and condenser. The units are equipped with copper enhanced tubing and steel tube sheet construction for heat exchangers. Condenser fans are ECM variable speed. The electrical enclosure is NEMA 4 rated and wired. Standard design pressure for the condenser is 150 psi. The chiller is leak and pressure tested at 200 psig at the high side and 150 psig at the low side, then evacuated and charged with refrigerant. The unit comes with a single source power connection and integral hydronic piping.

Usage Features

The chiller's operation is managed through a touchscreen interface panel (Schneider 10-inch HMI) connected to Danfoss MCX microprocessor controllers. This interface allows operators to monitor and modify temperatures, pressures, set points, alarms, and elapsed operating hours. It provides access to overall chiller functions and settings, including compressor parameters, chiller control settings, and device-specific controls for EXVs, fan banks, pumps, condensers, economizers, and hot gas bypass valves. The HMI software supports 1 to 4 compressors and both air-cooled or water-cooled configurations. It also offers visibility into external special controls and optional functionalities like free cooling, pump/plant control, BMS integration, and low-lift applications.

The chiller offers multiple setpoint control modes: User Setpoint, Digital Offset, Remote Setpoint, and Remote Offset, allowing flexible control based on site requirements. The Hand/Off/Auto function provides three modes: Off (no function, compressors off), Hand (chiller controls compressors based on leaving chilled water temperature setpoint), and Auto (requires an external hardwired signal for chiller enable).

For data management, the HMI provides primary displays for key performance indicators (KPIs), compressor and chiller states, evaporator and condenser specifics, and demand/capacity/speed. It also displays current status of hardwired digital and analog inputs/outputs. Trend data for temperatures, pressures, power, and fan speed is available, with Y-axis runtime zoom. The system allows customization of display units (imperial or metric).

BMS interconnectivity is standard, offering a comprehensive set of data points, status, alarms, and faults via Modbus RTU, Modbus IP, BACnet MS/TP, and BACnet IP protocols.

Maintenance Features

The manual outlines a comprehensive maintenance strategy focused on preventing equipment failure and extending service life. This includes weekly, quarterly, and annual inspections.

Inspection Methods:

Hands-on visual inspection: Checking components for temperature, texture, tightness, and dryness.
Physical condition checks: Inspecting insulation, compressors, valves, and sensors for damage or excessive vibration.
Electrical checks: Ensuring all electrical connections are secure, inspecting power distribution fuses, overload settings, and PCBs for dust buildup.
Refrigeration checks: Inspecting refrigerant pressures, verifying operation of IGVs, EXVs, and level sensors, and performing leak checks.
Water quality checks: Maintaining water/glycol mixture quality to prevent scaling and corrosion. Guidelines for pH, conductivity, total hardness, free chlorine, ammonia, sulphate, hydrogen carbonate, and chloride levels are provided. The use of a qualified water treatment specialist is recommended.
Condenser/Evaporator cleaning: Cleaning condenser tubes using appropriate equipment, performing clean water rinses, and checking tube integrity every 5 years or as needed. Chemical cleaning procedures are also outlined, emphasizing the need for a qualified water treatment specialist.
Compressor maintenance: Connecting to compressors using Service Monitoring Tools software to download event/fault logs, perform bearing calibrations, and verify adjustable settings.
Data logging: Extracting logs from the chiller and cleaning the SD card (if data logging is enabled).

Winter Shutdown Preparation:

Dry Layup: Draining chilled and condenser water barrels, removing bell ends, and blowing out tubes with nitrogen or air to ensure no water remains.
Wet Layup (Unheated Rooms): Filling barrels with an appropriate ethylene glycol solution for freeze protection.
Wet Layup (Heated Rooms): Consulting a chemical treatment company for correct water treatment.

Safety Warnings:

The manual emphasizes the importance of qualified personnel for installation and servicing, proper field wiring and grounding, and the use of Personal Protective Equipment (PPE) to protect against electrical, mechanical, and chemical hazards. Specific warnings are given for hazardous voltage, refrigerant under high pressure, and proper handling of coil cleaning agents.

Warranty:

Trane is not responsible for damages or claims resulting from improper long-term storage or deviations from recommended procedures. The chiller warranty is void if proper water/glycol mixture composition and quality are not maintained.