
2TTA2-IN-1B
18-AC51D3-3
Installer’s Guide
Condensing Units
2TTA2, 2TTA0
ALL phases of this installation must comply with NATIONAL, STATE AND LOCAL CODES
IMPORTANT — This Document is customer property and is to remain with this unit. Please return to service information
pack upon completion of work.
These instructions do not cover all variations in
systems nor provide for every possible contingency to
be met in connection with installation. All phases of
this installation must comply with NATIONAL, STATE
AND LOCAL CODES. Should further information be
desired or should particular problems arise which are not
covered sufficiently for the purchaser’s purposes, the matter
should be referred to your installing dealer or local distributor.
1
5 FT. ABOVE UNIT-UNRESTRICTED
A. GENERAL
The following instructions cover 2TTA2 and 2TTA0; Condensing Units.
NOTICE:
These outdoor units may be used with indoor units
equipped with Thermostatic Expansion Valve or Accutron™
Flow Control Check Valve (F.C.C.V.) assembly for refrigerant
flow control only.
Check for transportation damage after unit is uncrated.
Report promptly, to the carrier, any damage found to the unit.
To determine the electrical power requirements of the unit,
refer to the nameplate of the unit. The electrical power
available must agree with that listed on the nameplate.
B. LOCATION & PREPARATION OF THE UNIT
1. When removing unit from the pallet, notice the tabs on
the basepan. Remove tabs by cutting with a sharp tool as
shown in Figure 2 (see page 2).
2. The unit should be set on a level support pad at least as
large as the unit base pan, such as a concrete slab. If this
is not the application used please refer to application
bulletin “Trane APB2001-02”.
3. The support pad must NOT be in direct contact with any
structure. Unit must be positioned a minimum of 12"
from any wall or surrounding shrubbery to insure
adequate airflow. Clearance must be provided in front of
control box (access panels) & any other side requiring
service access to meet National Electrical Code. Also,
the unit location must be far enough away from any
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 sixty (60) feet.
7. If outdoor unit is mounted above the air handler, maximum lift should not exceed sixty (60) feet (suction line).
If air handler is mounted above condensing unit, maximum lift should not exceed sixty (60) feet (liquid line).
NOTE:
Refer to “Refrigerant Piping Software” Pub. No. 32-3312-02.
8. Locate and install indoor coil or air handler in accordance with instruction included with that unit.

Installer’s Guide
2
BASEPAN TAB REMOVAL
C. ACCUTRON™ FLOW CONTROL VALVE
If the indoor unit System Refrigerant Flow control is an
Accutron™ orifice and check valve assembly, an orifice size
change may be necessary. See Figure 3.
The outdoor model determines the required orifice size.
Check the listed orifice size on nameplate of the selected
outdoor model. If the indoor unit is factory shipped with a
different orifice size, the orifice must be changed to obtain
system rated performance.
IMPORTANT:
The outdoor unit is shipped with the proper size orifice and a
stick-on orifice size label in an envelope attached to the outdoor
unit. Outdoor unit nameplate will have correct orifice size
specified as BAYFCCV---A for rated performance.
D. 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
situation 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.
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.
E. SERVICE VALVE OPERATION
BRASS LIQUID AND GAS LINE SERVICE VALVES
The Brass Liquid and Gas Line Service Valves are 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 counterclockwise only until the stem contacts the rolled edge. (See
Figure 4) No torque is required.
BRASS GAS LINE BALL SERVICE VALVE
The Brass Gas Line Ball 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 Ball Service Valve is full open with a 1/4 turn. See
Figure 5.
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.
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.
© 2002 American Standard Inc. All Rights Reserved 18-AC51D3-3
3
BRAZE TYPE INDOOR END
SEALING CAP
ADAPTER
ACCUTRON
COMPONENTS
BODY
AS SHIPPED
TM
FLOW CONTROL
CHECK VALVE
(F.C.C.V.) ORIFICE
FIELD SUPPLIED
LIQUID LINE

Installer’s Guide
4
LIQUID LINE SERVICE VALVE
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 recommended that the pressure tap port valve
core be removed and a wet rag wrapped around
the valve body.
NOTICE:
Use care to make sure that no moisture enters pressure tap
port, while wet rag is being used.
NOTICE:
Precautions should be taken to avoid heat damage to
basepan during brazing. It is recommended to keep the
flame directly off of the basepan.
GAS LINE SERVICE VALVE
3. Attach center hose of manifold gauges to vacuum pump.
4. Evacuate until the micron gauge reads no higher than
350 microns.
5. Close off valve to vacuum pump and observe the micron
gauge. If gauge pressure rises above 500 microns in one (1)
minute, then evacuation is incomplete or system has a leak.
6. If vacuum gauge does not rise above 500 microns in one
(1) minute, the evacuation should be complete.
7. With vacuum pump and micron gauge blanked off, open
valve on HCFC-22 cylinder and charge refrigerant lines
and indoor coil with vapor to tank pressure of HCFC-22
supply.
NOTE:
DO NOT VENT REFRIGERANT INTO THE ATMOSPHERE.
7. Use a Dry Nitrogen Purge and Brazing Alloy without flux
when brazing the field line to the copper factory connection. Flow dry nitrogen into either valve pressure tap
port, thru the tubing and out the other port while brazing.
8. Braze using accepted good brazing techniques.
LEAK CHECK
IMPORTANT:
Replace pressure tap port valve core before attaching hoses for
evacuation.
After the brazing operation of refrigerant lines to both the
outdoor and indoor unit is completed, the field brazed
connections must be checked for leaks. Pressurize through
the service valve ports, the indoor unit and field refrigerant
lines with dry nitrogen to 350-400 psi. Use soap bubbles or
other leak-checking methods to see that all field joints are
leak-free! If not, release pressure; then repair!
SYSTEM EVACUATION
NOTE:
Since the outdoor unit has a refrigerant charge, the gas and
liquid line valves must remain closed.
1. Upon completion of leak check, evacuate the refrigerant
lines and indoor coil before opening the gas and liquid
line valves.
2. Attach appropriate hoses from manifold gauge to gas
and liquid line pressure taps.
NOTE:
Unnecessary switching of hoses can be avoided and
complete evacuation of all lines leading to sealed system
can be accomplished with manifold center hose and
connecting branch hose to a cylinder of HCFC-22 and
vacuum pump.
8. Close valve on HCFC-22 supply cylinder. Close valves
on manifold gauge set and remove refrigerant charging
hoses from liquid and gas pressure tap ports.
NOTE:
A 3/16" Allen wrench is required to open liquid line service
valve. A 1/4" Open End or Adjustable wrench is required
to open gas line valve. A 3/4" Open End wrench is required
to take off the valve stem cap.
9. The liquid line shut-off valve can now be opened. Remove
shut-off valve cap. Fully insert hex wrench into the stem
and backout counterclockwise until valve stem just touches
5
GAS LINE BALL SERVICE VALVE
UNIT SIDE
OF VALVE
COOLING
CAP
PRESSURE TAP PORT
GAS LINE CONNECTION
CAP
CORE
1/4 TURN ONLY
COUNTERCLOCKWISE
FOR FULL OPEN
POSITION
VALVE STEM
BODY
18-AC51D3-3 3