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Piping and Connections
system and testing all fittings and joints to verify that the
system is leak-free, insulate suction lines to prevent heat
gain and unwanted condensation.
Components
Installing the suction line requires field installation of these
components: a filter, access port, and a Frostat™ control
when the refrigerant coil is used with Trane condensing
units. Position them as close to the compressor as
possible.
Note: Placement of the Frostat control is illustrated in
Figure 48, p. 56
•
Filter: The suction filter prevents contaminants,
introduced during installation, from entering the
compressor. For this reason, the suction filter should be
the replaceable-core type, and a clean core should be
installed after the system is cleaned up.
•
Access port: The access port is used to determine
suction pressure. This port is usually a Schraeder valve
with a core.
•
Frostat™ coil frost protection: The Frostat control is the
preferred method for protecting evaporator coils from
freezing when the refrigerant coil is used with Trane
condensing units. It senses the suction-line
temperature and temporarily disables mechanical
cooling if it detects frost conditions. The control is
mechanically attached to the outside of the refrigerant
line, near the evaporator, and wired to the unit control
panel.
•
Ball shutoff valve: Adding manual, ball-type shutoff
valves upstream and downstream of the filter simplifies
replacement of the filter core.
Expansion Valves
Expansion valves meter refrigerant into the evaporator
under controlled conditions. If there is too much refrigerant,
the refrigerant will not completely vaporize and the
remaining liquid will slug the compressor. If there is too little
refrigerant, there may not be enough cooling for the
compressor.
Expansion valve requirements vary based on condensing
unit design. Consult the product literature for the
condensing unit to be used for proper valve selection.
Remodel, Retrofit, or
Replacement
Inevitably, older condensing units and evaporator systems
needs to be replaced or retrofitted. Due to the phase-out of
many of these older refrigerants, the major components for
those older units or systems may no longer be available.
The only option will be to convert the system to R-410A,
POE oil, and R-410A components.
When upgrading an existing refrigerant split system due to
remodel, retrofit, or replacement, the entire system must be
reviewed for compatibility with R-410A and POE oil. Each
58
and every part of the split HVAC system MUST be
compatible with the properties of R-410A refrigerant and
POE oil. In addition, ensure the existing electrical service is
adequate for the product being installed.
WARNING
R-410A Refrigerant under Higher
Pressure than R-22!
Failure to use proper equipment or components as
described below, could result in equipment failing and
possibly exploding, which could result in death,
serious injury, or equipment damage.
The units described in this manual use R-410A
refrigerant which operates at higher pressures than R-
22. Use ONLY R-410A rated service equipment or
components with these units. For specific handling
concerns with R-410A, please contact your local
Trane representative.
Every part of an existing split system needs to be analyzed
to determine if it can be reused in an R-410A and POE oil
system:
•
R-22 condensing units will not work with R-410A; they
must be replaced.
•
Most older evaporator coils were not pressure- and
cycle-rated for R-410A pressures. If they weren't, they
will need to be replaced. If they were properly pressure-
rated for R-410A, existing coils must be modeled to
determine if they will meet capacity requirements, are
properly circuited, have correctly sized distributor
tubes, and employ acceptable distributors and orifices.
•
The required R-410A line sizes may be different than
the existing line sizes. The lines need to be re-sized
and compared to existing lines for reusability.
•
Suction lines 2-5/8 OD and smaller of type L copper are
suitable for use with R-410A. Suction lines 3-1/8 OD
must use type K or thicker wall.
•
Discharge lines, liquid lines, heat pump vapor lines,
and hot gas bypass lines 1-3/8 OD and smaller of type
L copper are suitable for use with R-410A. These same
lines sized at 1-5/8 OD or 2-1/8 OD must use type K or
thicker wall.
•
Expansion valves need to be reselected. Expansion
valves are refrigerant specific.
•
Any gasket or O-ring should be replaced. Shrinkage of
the original seal may occur after an HFC conversion,
potentially causing a refrigerant leak. Components
commonly affected are Schraeder cores, solenoid
valves, ball valves, and flange seals. But all external
seals in contact with refrigerant should be viewed as
potential leak sources after a retrofit.
•
All other valves, filters, valve packing, pressure
controls, and refrigeration accessories must be
researched through their manufacturer for compatibility
with the pressures of an R-410A system, and for their
compatibility with the newer POE oil.
BCX-SVX002A-EN
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