Coil Piping and Connections
48 CLCH-SVX009L-EN
Figure 52. Single-circuit condensing unit: evaporator coil with four distributors
1. Pitch the liquid line slightly – 1 in./10 feet – so that
the refrigerant drains toward the evaporator.
2. Provide one expansion valve per distributor.
3. Slightly pitch the outlet line from the suction header
toward the suction riser – 1 in./10 feet in the
direction of flow. Use the tube diameter that
matches the suction-header connection.
4. This looks like a trap, but is actually due to the
requirement that the refrigerant gas leaving the coil
flows downward, past the lowest suction-header
outlet, before turning upward. Use the double-elbow
configuration to isolate the TXV bulb from other
suction headers.
5. Use the “horizontal” tube diameter as specified in
the condensing unit application manual.
6. Use the tube diameter recommended for a vertical
rise as specified in the condensing unit application
manual. Ensure that the top of the riser is higher
than the evaporator coil.
7. Pitch the suction line slightly – 1 in./10 feet – so that
the refrigerant drains toward the evaporator.
8. Insulate the suction line.
9. Only use a “trim” solenoid valve for constant-
volume, humidity-sensitive applications. For all
other applications, install a single solenoid valve
(the “pumpdown” solenoid valve) between the
liquid-line filter drier and the sight glass.
Note: Due to reduced coil volume in condensing units
with microchannel heat exchanger condenser,
do not use trim solenoid valves for these units.
Thermal expansion
valves (TXV)
Liquid
line
Filter drier
“Pumpdown”
solenoid valve
Sight
glass
Distributor
“Trim”
solenoid valve
Suction line
Evaporator Coil with Horizontal-Split
(Standard) Circuiting
Thermal expansion
valves (TXV)
Liquid
line
Filter drier
Sight
glass
Distributor
Suction line
Evaporator Coil with Intertwined Circuiting
“Pumpdown”
solenoid valve
“Trim”
solenoid valve
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