Coil Piping and Connections
CLCH-SVX009L-EN 47
Figure 51. Single-circuit condensing unit: evaporator coil with two distributors
1. Pitch the liquid line slightly – 1 inch/10 feet – so 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 inch/10 feet in the
direction of flow. Use the tube diameter that
matches the suction-header connection. Use a
double-elbow configuration to isolate the TXV bulb
from other suction headers.
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.
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. Assure the top of the riser is higher than the
evaporator coil.
7. Pitch the suction line slightly –1 inch/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
valve (TXV)
Liquid
line
Filter drier
“Pump-down”
solenoid valve
Sight
glass
Distributor
“Trim”
solenoid valve
Suction line
Evaporator Coil with Horizontal-Split
(Standard) Circuiting
Thermal
expansion
valve (TXV)
Liquid
line
Filter drier
Solenoid
valve
Sight
glass
Distributor
Suction line
Evaporator Coil with Intertwined Circuiting
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