Trane 4TWA3 User Manual

SSP-SVN04A-EN

18-BC62D1-1

Installer’s Guide

Heat Pumps

4TWA3

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 informa-

tion 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.

A. GENERAL

!

WARNING

This information is intended for use by individuals posses­sing adequate backgrounds of electrical and mechanical
experience. Any attempt to repair a central air conditioning
product may result in personal injury and or property
damage. The manufacturer or seller cannot be responsible
for the interpretation of this information, nor can it assume
any liability in connection with its use.

NOTICE:
Trane has always recommended installing Trane approved
matched indoor and outdoor systems.

The benefits of installing approved matched systems are
maximum efficiency, optimum performance and best
overall system reliability.

!

WARNING

These units use R-410A refrigerant which operates at 50 to
70% higher pressures than R-22. Use only R-410A approved
service equipment. Refrigerant cylinders are painted a
“Rose” color to indicate the type of refrigerant and may
contain a “dip” tube to allow for charging of liquid refriger­ant into the system. All R-410A systems use a POE oil that
readily absorbs moisture from the atmosphere. To limit this
“hygroscopic” action, the system should remain sealed
whenever possible. If a system has been open to the
atmosphere for more than 4 hours, the compressor oil
must be replaced. Never break a vacuum with air and
change the driers when opening the system for component
replacement. For specific handling concerns with R-410A
and POE oil, reference Retrofit Bulletin TRN-APG02-EN.

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.

always

!

CAUTION

UNIT CONTAINS R-410A REFRIGERANT!

R-410A OPERATING PRESSURE EXCEEDS THE
LIMIT OF R-22. PROPER SERVICE EQUIPMENT IS
REQUIRED. FAILURE TO USE PROPER SERVICE
TOOLS MAY RESULT IN EQUIPMENT DAMAGE OR
PERSONAL INJURY.

SERVICE

USE ONLY R-410A REFRIGERANT AND

APPROVED POE COMPRESSOR OIL.

1

The Weathertron® Heat Pump has been designed and 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 recommended 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

2. If possible, avoid locations that are likely to accumulate

5 FT. ABOVE UNIT — UNRESTRICTED

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.

snow drifts. If not possible, a snow drift barrier should be
installed around the unit to prevent a build-up of snow on

Installer’s Guide

2

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.

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.

BASEPAN TAB REMOVAL

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 above in 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 XR-APG**-EN” (* denotes latest
revision number).

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 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 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.

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 rated connecting line. Unit
nameplate charge is with twenty-five (25) feet of line set.

Final refrigerant charge adjustment is necessary. Use
the Charging Information in the outdoor unit Service Facts
and on page 6.

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 and Gas Line Service Valves are factory
shipped in the seated position to hold factory charge. The

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LIQUID LINE SERVICE VALVE

C. INSTALLING REFRIGERANT LINES

!

CAUTION

If using existing refrigerant lines make certain that all joints
are brazed, not soldered.

© 2006 American Standard Inc. All Rights Reserved 18-BC62D1-1

Installer’s Guide

4

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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).

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 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 dam-

age 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.

GAS LINE BALL SERVICE VALVE

UNIT SIDE
OF VALVE

PRESSURE TAP PORT

CAP

GAS LINE CONNECTION

1/4 TURN ONLY
COUNTERCLOCKWISE
FOR FULL OPEN
POSITION

VALVE STEM

GAS LINE SERVICE VALVE

!

WARNING

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 units 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 R-410A and vacuum pump.

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. Blank off vacuum pump and micron gauge, close valves
on manifold gauge set.

NOTE:
DO NOT VENT REFRIGERANT INTO THE ATMOSPHERE.

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.

8. 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 rolled edge (approximately five [5] turns) observ­ing WARNING statement on page 3. See Figure 3.

9. Replace liquid service pressure tap port cap and valve
stem cap. These caps MUST BE REPLACED to prevent
leaks. Replace valve stem and pressure tap cap finger
tight, then tighten an additional 1/6 turn.

18-BC62D1-1 3