Piping and Connections
CLCH-SVX07K-EN 111
Figure 142. Typical single-circuit condensing unit: evaporator coil with four distributors
1. Pitch the liquid line slightly—1 inch/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 inch/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 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
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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