Trane CSAA Installation, Operation And Maintenance Manual page 113

Figure 144. Typical dual-circuit condensing unit: evaporator coil with four distributors
with Horizontal-Split (Standard) Circuiting
Suction line
(circuit 2)
Suction line
(circuit 1)
Evaporator Coil with Intertwined Circuiting
Suction lines
CLCH-SVX07K-EN
Evaporator Coil
Thermal expansion
valves (TXV)
Solenoid
valve
Sight
glass
Distributor
Thermal expansion
valves (TXV)
Sight
glass
Solenoid
Distributor
1. Pitch the liquid line slightly—1 inch/10 feet —so
that the refrigerant drains toward the
evaporator.
Liquid line
2. Provide one expansion valve per distributor.
(circuit 2)
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.
Liquid line
4. This looks like a trap, but is actually due to the
(circuit 1)
requirement that the refrigerant gas leaving the
coil flows downward, past the lowest suction-
header outlet, before turning upward. Use the
Filter drier
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
Liquid line
application manual. Ensure that the top of the
(circuit 2)
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.
valve
8. Insulate the suction line.
9. The top of the Circuit 1 suction riser must be
Liquid line
(circuit 1)
higher than the bottom evaporator coil. Use the
tube diameter recommended for a vertical rise
as specified in the condensing unit application
Filter drier
manual.
10. The top of the Circuit 2 suction riser must be
higher than the top evaporator coil. Use the tube
diameter recommended for a vertical rise as
specified in the condensing unit application
manual.
Piping and Connections
113