12
TWA-SVX01A-EN
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 seal caps until prepared to
braze refrigerant lines to the connections. Extended
exposure to atmosphere may allow moisture or dirt to
contaminate the system, damaging valve seats 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 con-
nections 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.
System Evacuation
1. After completion of leak check, evacuate the system.
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-22 and
vacuum pump.
3. Attach center hose of manifold gauages to vacuum pump.
4. Evacuate the system to hold a 350 micron vacuum.
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 the 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 R-22 cylinder and allow refrigerant pressure to
build up to about 40 psig.
8. Close valve on the R-22 supply cylinder. Close valves on
manifold gauge set and remove refrigerant charging hoses
from liquid and gas gauge ports.
9. Leak test the entire system. Using proper procedures and
caution, repair any leaks found and repeat the leak test.
Refrigerant Charging Procedure
If charging by weight, refer to refrigerant charges that are
given in Table 3. If additional refrigerant is needed because
of length of line, calculate the requirement using Table 4.
Charge by weight through the gauge port on the liquid line.
Once the charge enters the system, backseat (open) the
liquid line service valve and disconnect the charging line
and replace the cap on the gauge port.
Insulating and Isolating Refrigerant Lines
Insulate the entire suction line with refrigerant piping insula-
tion. Also insulate any portion of the liquid line exposed to
temperature extremes. Insulate and isolate liquid and suction
lines from each other. Isolate refrigerant lines from the
structure and any duct work.
Note:
To prevent possible noise or vibration problems, be
certain to isolate refrigerant lines from the building.
Table 3 - TWA Refrigerant Charge (R-22)
1
Model Number
Refrigerant Charge
TWA090A
18 lbs. 0.0 oza.
TWA075A
TWA120A
31 lbs. 8.0 ozs.
TWA100A
TWA180B
18 lbs. 0.0 ozs. (per circuit)
TWA155B
TWA240B
22 lbs. 4.0 ozs. (per circuit)
TWA200B
1
Sufficient operating charge for outdoor unit and
25 feet of nominally sized refigerant piping.
Table 4 - Additional Required Refrigerant
Additional Additional
R-22
Tubing Length
Required (lbs.)
15 ft.
1 lb. 4 oz.
25 ft.
2 lbs. 1 oz.
32 ft.
2 lbs. 11 oz.
40 ft.
3 lbs. 5 oz.
¹ Based on 1-3/8" dia. Suction line, 1/2" liquid line.
² Add .5 lbs. R-22 for each additional six feet of
tubing length over 40 feet.
Installation
