Trane UCCA Installation, Operation And Maintenance Manual page 40

Coil Piping and Connections
Figure 36. Single-Circuit Condensing Unit: Evaporator Coil with Four Distributors
suction line
distributor
suction line
40
thermal expansion
valves (TXV)
"trim"
solenoid valve
"pumpdown"
solenoid valve
Intertwined Circuiting
thermal expansion
valves (TXV)
"trim"
solenoid valve
"pumpdown"
solenoid valve
distributor
1. Pitch the liquid line slightly—1 inch/10 feet —so
Evaporator Coil
that the refrigerant drains toward the
with Horizontal-Split
(Standard) Circuiting
evaporator.
2. Provide one expansion valve per distributor.
liquid
line
3. Slightly pitch the outlet line from the suction
header toward the suction riser— 1 inch/10 feet
sight
glass
in the direction of flow. Use the tube diameter
that matches the suction-header connection.
filter drier
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.
Evaporator Coil with
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
liquid
application manual. Ensure that the top of the
line
riser is higher than the evaporator coil.
sight
glass
7. Pitch the suction line slightly—1 inch/10 feet —
so that the refrigerant drains toward the
filter drier
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.
CLCH-SVX009A-EN