Trane Custom Climate Changer Air Handlers Installation Refrigerant Coil Piping, Liquid Lines

Installation

Refrigerant Coil Piping

Note: Refer to the “Protecting the Environment” section on page 3 for information on handling refrigerants.

Use Figure 33 to determine the proper, relative sequence of the components in the refrigerant lines that connect the condensing unit to an evaporator coil. Refer to the “Examples of Field-Installed Evaporator Piping” section on page 35 for more detailed schematics of evaporator piping.

Liquid Lines

Line Sizing. Properly sizing the liquid line is critical to a successful split- system application. The selected tube diameter must provide at least 5°F [2.7°C] of subcooling at the expansion valve throughout the operating envelope. Increasing the size of the liquid line will not increase the available subcooling.

Routing. Install the liquid line with a slight slope in the direction of flow so that it can be routed with the suction line. Minimize tube bends and reducers because these items tend to increase pressure drop and to reduce subcooling at the expansion valve. Liquid line receivers, other than those that are factory-installed, are not recommended.

Insulation. The liquid line is generally warmer than the surrounding air, so it does not require insulation. In fact, heat loss from the liquid line improves system capacity because it provides additional subcooling.

Components. Liquid-line refrigerant components necessary for a successful job include a filter drier, access port, solenoid valve, moisture-indicating sight glass, expansion valve(s), and ball shutoff valves. Figure 33 illustrates the

proper sequence for positioning them in the liquid line. Position the components as close to the evaporator as possible.

• Filter drier. There is no substitute

for cleanliness.during system

installation. The filter drier

prevents residual contaminants,

introduced during installation,

from entering the expansion

valve and solenoid valve.

• Access port. The access port

allows the unit to be charged

with liquid refrigerant and is

used to determine subcooling.

This port is usually a Schraeder

valve with a core.

• Solenoid valve. In split systems,

solenoid valves isolate the

refrigerant from the evaporator

during off cycles; under certain

conditions, they may also trim

the amount of active evaporator

as compressors unload.

Generally, the “trim” solenoid

valve is unnecessary for variable-

air-volume comfort-cooling

applications, and is only required

Figure 33. Example of placement for split-system components

Kit with Kit Kit

Kit with sensor 13790452010 SEN-01212

Kit with switch - X13100429010 THT 02442

for constant-volume applications

when dehumidification is a

concern.

• Moisture-indicating sight glass.

Be sure to install one moisture-

indicating sight glass in the main

liquid line. The only value of the

sight glass is its moisture

indication ability. Use actual

measurements of temperature

and pressure—not the sight

glass—to determine subcooling

and whether the system is

properly charged. The moisture

indicator/sight glass must be

sized to match the size of the

liquid line at the thermal

expansion valve.

CAH-SVX01A-EN 33