Trane TTA240F Series Installation Operation & Maintenance page 9

Refrigerant Piping Procedures
(Outdoor Units)
Each TTA unit ships with a holding
charge of dry nitrogen. The nitrogen
should be removed and the entire
system evacuated (at the proper time)
to avoid possible contamination.
1. Remove the compressor service
access panel.
2. Locate the liquid and suction line
service valves. Check that the
piping connection stubs on the
valves (Figure 3) line up properly
with the holes in the unit cabinet.
Figure 3.
3. Remove the refrigerant
connection seal caps and open
the service valve slowly to release
the nitrogen from the unit.
CAUTION
Do not remove the seal caps from
refrigerant connections, or open the
service valves until prepared to braze
refrigerant lines to the connections.
Excessive exposure to atmosphere
(> 5 min.) may allow moisture or dirt
to contaminate the system, damaging
valve seals and causing ice formation
in system components.
4. Cut, fit and braze tubing, starting
at the outdoor unit and work
toward the indoor unit.
Note: Use long radius ells for all 90
degree bends.
All brazing should be done using a 2
to 3 psig dry nitrogen purge flowing
through the pipe being brazed,
Figure 3.
TTA-SVN03A-EN
Installation
CAUTION
Install a regulating valve between the
nitrogen source and the gauge
manifold (Figure 3). Unregulated
pressure can damage system
components.
CAUTION
Wet-wrap all valves and protect
painted surfaces from excessive heat.
Heat can damage system
components and the unit finish.
5. Shut off nitrogen supply.
6. Shut off the manifold valve for the
line that is connected to the
suction line service valve.
Disconnect the line from the
gauge port on the valve.
Figure 4.
Refrigerant Piping Procedure
(Indoor Unit)
Once liquid and suction lines are
complete to the refrigerant
connections on the indoor unit,
puncture the seal caps on the indoor
unit connection stubs to release the
dry nitrogen charge.
CAUTION
Do not apply heat to remove seal caps
until they have been punctured. If seal
caps are intact, application of heat
may generate excessive pressure in
the unit and result in damage to the
coil or expansion valve.
1. Remove both seal caps from the
indoor unit connection stubs.
CAUTION
Do not remove the seal caps from
refrigerant connections, or open the
service valves until prepared to braze
refrigerant lines to the connections.
Excessive exposure to atmosphere
(> 5 min.) may allow moisture or dirt
to contaminate the system, damaging
valve seals and causing ice formation
in system components.
2. Turn nitrogen supply on. Nitrogen
enters thorough liquid line gauge
port.
3. Braze the liquid line connections.
4. Open the gauge port on the
suction line and then braze the
suction line to the connection
stub. Nitrogen will bleed out the
open gauge port on the suction
line.
5. Shut off nitrogen supply.
Leak Check
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 the system
through the service valve with dry
nitrogen to 200 psi. Use soap bubbles
or other leak-checking methods to
ensure that all field joints are leak
free. If not, release pressure, repair
and repeat leak test.
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