Trane 4TWR4 Installer's Manual page 3

5
GAS LINE SERVICE VALVE
CAP
UNIT SIDE
OF VALVE
PRESSURE TAP PORT
CAP
COOLING
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 refriger-
ant 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.
E. 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 4) No torque is required.
18-BC51D1-3
1/4 TURN ONLY
COUNTERCLOCKWISE
FOR FULL OPEN
POSITION
VALVE STEM
GAS LINE CONNECTION
BODY
HEATING
CORE
Installer's Guide
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 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. 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.
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