Trane 2TWA2, 2TWA0 User Manual
2TWA2-IN-1A
18-BC51D3-2
Installer’s Guide
Heat Pumps
2TWA0, 2TWA2
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 2TWA Heat Pump 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.
®
The Weathertron
manufactured to withstand and operate in severe winter
conditions. However, there are precautionary steps which
should be taken at the time of installation which will help
assure the efficient operation of the unit. It is recom-
mended that these precautions be taken for units
being installed in areas where snow accumulation and
prolonged below freezing temperatures occur.
1. Units should be elevated 3 to 12 inches above the pad or
rooftop, depending on local weather. This additional
height will allow better drainage of snow and ice (melted
during defrost cycle) prior to its refreezing. This should
prevent a build-up of ice around the unit which occurs
when unit is not elevated. Insure that drain holes in
unit base pan are not obstructed preventing
draining of defrost water.
2. If possible, avoid locations that are likely to accumulate
snow drifts. If not possible, a snow drift barrier should be
installed around the unit to prevent a build-up of snow
on the sides of the unit and should be of sufficient
distance from the unit to prevent restriction of airflow to
and from the unit. Also allow for proper maintenance
space. The barrier should be constructed of materials
which will blend in with the building design.
Heat Pump has been designed and
3. Avoid locating the unit where condensation and freezing
of defrost vapor may annoy the customer. For instance,
installing the unit under a bedroom, kitchen, or picture
window may be annoying to the customer since condensate and fog will occur during the defrost cycle.
4. Avoid locating the unit under the eaves or other overhead structures as sizeable icicles may form and the unit
may be damaged by these falling icicles.
B. LOCATION AND 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 on page 2, Figure 2, and slide unit off of pallet.
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) and any other side requiring
service access to meet National Electrical Code. Also, the
unit location must be far enough away from any struc-
Installer’s Guide
2
ture 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 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).
8. Locate and install indoor coil or air handler in accordance with instruction included with that unit.
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.
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.
3
BRAZE TYPE INDOOR END
TM
ACCUTRON
COMPONENTS
SEALING CAP
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.
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.
4
LIQUID LINE SERVICE VALVE
ADAPTER
FLOW CONTROL
CHECK VALVE
(F.C.C.V.) ORIFICE
BODY
AS SHIPPED
FIELD SUPPLIED
LIQUID LINE
© 2002 American Standard Inc. All Rights Reserved 18-BC51D3-2
Installer’s Guide
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
HEATING
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 and Gas Line Service Valves. Turn valve stem
counterclockwise only until the stem contacts the rolled
edge. (See Figures 4 and 6) No torque is required.
BRASS GAS LINE BALL 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 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.
5. Do NOT allow uninsulated liquid line to come in direct
contact with bare gas line.
6
GAS LINE SERVICE VALVE
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.
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.
18-BC51D3-2 3
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