© 2009 Trane
18-AC55D1-4
Installer’s Guide
structure to prevent excess roof run-off water from
pouring directly on the unit. Do not locate unit(s) close
to bedroom(s).
4. The top discharge area must be unrestricted for at least
five (5) feet above the unit.
5. When the outdoor unit is mounted on a roof, be sure the
roof will support the unit’s weight. Properly selected
isolation is recommended to prevent sound or vibration
transmission to the building structure.
6. The maximum length of refrigerant lines from outdoor to
indoor unit should NOT exceed eighty (80) feet.
7. If outdoor unit is mounted above the air handler, maxi-
mum lift should not exceed twenty-five (25) feet (suction
line). If air handler is mounted above condensing unit,
maximum lift should not exceed twenty-five (25) feet
(liquid line).
NOTE:
Refer to “Refrigerant Piping Software” Pub. No. 32-3312-0*,
and “Refrigerant Piping Manual” Pub. No. 32-3009-0* (the
position of the * denotes latest revision number).
8. Locate and install indoor coil or air handler in accor-
dance with instruction included with that unit.
C. INSTALLING REFRIGERANT LINES
CAUTION
!
If using existing refrigerant lines make certain that all joints
are brazed, not soldered.
Condensing units have provisions for braze connections.
Pressure taps are provided on the service valves of outdoor
unit for compressor suction and liquid pressures.
The indoor end of the recommended refrigerant line sets may
be straight or with a 90 degree bend, depending upon situa-
tion requirements. This should be thoroughly checked out
before ordering refrigerant line sets.
The gas line must always be insulated.
CAUTION
!
In scroll compressor applications, dome temperatures may
be hot. Do not touch top of compressor, may cause minor
to severe burning.
The units are factory charged with the system charge
required when using fifteen (15) feet of connecting line. Unit
nameplate charge is the same.
Final refrigerant charge adjustment is necessary.
Use
the Charging Charts in the outdoor unit Service Facts.
1. Determine the most practical way to run the lines.
2. Consider types of bends to be made and space limitations.
NOTE:
Large diameter tubing will be very difficult to rebend once it
has been shaped.
3. Determine the best starting point for routing the
refrigerant tubing — INSIDE OR OUTSIDE THE
STRUCTURE.
4. Provide a pull-thru hole of sufficient size to allow both
liquid and gas lines.
5. Be sure the tubing is of sufficient length.
6. Uncoil the tubing — do not kink or dent.
7. Route the tubing making all required bends and properly
secure the tubing before making connections.
8. To prevent a noise within the building structure due to
vibration transmission from the refrigerant lines, the
following precautions should be taken:
a. When the refrigerant lines have to be fastened to floor
joists or other framing in a structure, use isolation
type hangers.
b. Isolation hangers should also be used when refriger-
ant lines are run in stud spaces or enclosed ceilings.
c. Where the refrigerant lines run through a wall or sill,
they should be insulated and isolated.
d. Isolate the lines from all ductwork.
D. SERVICE VALVE OPERATION
BRASS LIQUID LINE SERVICE VALVE
The Brass Liquid Line Service Valve is factory shipped in the
seated position to hold factory charge. The pressure tap
service port (when depressed) opens only to the field brazing
side of the valve when the valve is in the seated position.
The liquid line valve is
not
a back seating valve (see
WARNING
below).
WARNING
!
Extreme caution should be exercised when opening the
Liquid Line Service Valve. Turn valve stem counterclock-
wise only until the stem contacts the rolled edge. (See
Figure 3) No torque is required.
BRASS GAS LINE SERVICE VALVE
The Brass Gas Line Service Valve is shipped in the closed
position to hold the factory refrigerant charge. The pressure
tap service port (when depressed) opens only to the field
brazing side when the valve is in the closed position. The Gas
Line Service Valve is full open with a 1/4 turn. See Figure 4.
BRAZING REFRIGERANT LINES
1. Remove lower access cover to access service valves.
2. Before brazing, remove plugs from external copper stub
tubes. Clean internal and external surfaces of stub
tubes prior to brazing.
3. Cut and fit tubing, minimizing the use of sharp
90° bends.
4. Insulate the entire gas line and its fittings.
5. Do
NOT
allow uninsulated liquid line to come in direct
contact with bare gas line.
6. Precautions should be taken to avoid heat damage
to the pressure tap valve core during brazing. It is
BASEPAN TAB REMOVAL
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