Suction Lines - Trane Performance Climate Changer Installation, Operation And Maintenance Manual

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NOTICE:
Valve Damage!
Disassemble the thermal expansion valve before completing the brazing connections. If
necessary, wrap the valve in a cool, wet cloth while brazing. Failure to protect the valve from
high temperatures could result in damage to internal components.
Figure 77. Type F refrigerant coil with packed elbow
Panel
Coil

Suction Lines

Line sizing
Proper suction-line sizing is required to guarantee the oil returns to the compressor throughout the
system's operating envelope. At the same time, the line must be sized so that the pressure drop
does not excessively affect capacity or efficiency. To accomplish both objectives, it may be
necessary to use two different line diameters: one for the horizontal run and for vertical drops, and
another for the vertical lifts.
Routing
To prevent residual or condensed refrigerant from "free-flowing" toward the compressor, install
the suction line so it slopes slightly—that is, by ¼ inch to 1 inch per 10 feet of run—toward the
evaporator. When the application includes a suction riser, oil must be forced to travel the height
of the riser. Riser traps and double risers are unnecessary in the suction line when the refrigerant
coil is used with Trane condensing units.
Avoid putting refrigerant lines underground. Refrigerant condensation or installation debris inside
the line, service access, and abrasion/corrosion can quickly impair reliability.
Insulation
Any heat that transfers from the surrounding air to the cooler suction lines increases the load on
the condenser (reducing the system's air-conditioning capacity) and promotes condensate
CLCH-SVX07C-EN
Thermal expansion valve. The expansion valve is the throttling device that meters the
refrigerant into the evaporator coil. Metering too much refrigerant floods the compressor;
metering too little elevates the compressor temperature. Choosing the correct size and type of
expansion valve is critical to assure it will correctly meter refrigerant into the evaporator coil
throughout the entire operating envelope of the system. Correct refrigerant distribution into the
coil requires an expansion valve for each distributor.
Perforated plate
(packed elbow)
The thermal expansion valve must be selected
for proper size and capacity. The size of the
Cut here
expansion valve should cover the full range of
for piping
loadings. Check that the valve will successfully
operate at the lightest load condition. For
improved modulation, choose expansion
valves with balanced port construction and
external equalization.
Cut the process tube and cap assembly from the
liquid connection as shown in
install the expansion valve directly to the liquid
Venturi type
distributor
connections.
Coil Piping and Connections
Figure 77 and
87