Trane UCCA Installation, Operation And Maintenance Manual page 39

Figure 35. Single-circuit condensing unit: evaporator coil with two distributors
suction line
distributor
suction line
distributor
CLCH-SVX009A-EN
with Horizontal-Split
"trim"
(Standard) Circuiting
solenoid valve
liquid
line
sight
thermal
glass
expansion
valve (TXV)
filter drier
"pump-down"
solenoid valve
Intertwined Circuiting
liquid
line
sight
glass
solenoid
filter drier
valve
thermal
expansion
valve (TXV)
1. Pitch the liquid line slightly—1 inch/10 feet —so
Evaporator Coil
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-
Evaporator Coil with
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.
Coil Piping and Connections
39