Trane CAUJ-C20 User Manual

CAUJ-SVX01E-EN
35
• Maximum allowable pressure drop: 7 psig (1°F)
As the pressure drop in the liquid line increases, the
potential for liquid flashing, due to reduced refrigerant
pressure corresponding to a reduced liquid
temperature (subcooling), increases. Under these
conditions, liquid lines exposed to high surrounding
ambient temperatures must be insulated.
NNoottee:: Adding refrigerant to a system with improperly
sized refrigerant lines will only decrease system
performance and reliability and accentuate poor
operating condition.
Isolate all refrigerant lines from the building. This
prevents transferring line vibration to the structure. Do
not secure the lines rigidly to the building at any point
since this will defeat the isolation system of the unit.
See connection drawings in Dimension and Weights
chapter for refrigerant line size connections and
locations. Connect the liquid line piping to the stubs
provided at the liquid line shutoff valves.
NNoottee:: The installer must cut an appropriately-sized
opening in the unit sheet metal for the
refrigerant piping entrance into the unit.
Discharge (Hot Gas) Lines
Discharge lines should be pitched downward 1/2 inch
for each 10 feet of horizontal run in the direction of hot
gas flow and away from the compressor. Insulate any
portion of the discharge piping that is exposed to
outdoor ambient temperature.
Discharge line sizing is based on minimum velocity
required for good oil movement in system.
Basic discharge line parameters are:
• Maximum allowable pressure drop: 6 psig
• Maximum velocity: 3500 fpm
Minimum velocities at Minimum Load:
• Horizontal Lines: 500 fpm
• Vertical Lines: See table below.
A double riser system may be necessary to meet the
discharge line velocity requirements.
When either a single or double discharge riser is used,
the line should drop well below the discharge outlet of
the compressor before starting the vertical rise to
prevent the possibility of refrigerant draining back to
the compressor during the “Off” cycle.
Table 12. Minimum vertical line velocities
Line Dia.
Minimum
Velocity
(fpm)
Line
Dia.
Minimum
Velocity (fpm)
7/8"
470
2-1/8"
750
1-1/8"
540
2-5/8"
825
Table 12. Minimum vertical line velocities (continued)
Line Dia.
Minimum
Velocity
(fpm)
Line
Dia.
Minimum
Velocity (fpm)
1-3/8"
600
3-1/8"
915
1-5/8"
650
3-5/8"
975
Final Refrigerant Pipe Connections
To access the refrigerant pipe connections, remove the
louvered side grills. See connection drawings in
Dimensions and Weights chapter..
These condensing units are shipped with a Nitrogen
holding charge. Install pressure gauges to the
appropriate access valve(s) and take a reading.
• If no pressure is present, see Leak Testing
Procedure section.
• If pressure is present, relieve the pressure before
attempting to unsweat the “seal” caps.
• If refrigerant connections are not capped, but are
“spun-end” tubes, use a tubing cutter to remove
the end from the pipe.
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Trane CAUJ-C20 Specifications

General

Brand	Trane
Model	CAUJ-C20
Category	Air Conditioner
Language	English