18-AC55D1-4
3
Installer’s Guide
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 connec-
tion. 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 300 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. With vacuum pump and micron gauge blanked off, open
valve on R-410A cylinder and charge refrigerant lines and
indoor coil with vapor to tank pressure of R-410A supply.
NOTE:
DO NOT VENT REFRIGERANT INTO THE ATMOSPHERE.
8. Close valve on R-410A supply cylinder. Close valves on
manifold gauge set and remove refrigerant charging
hoses from liquid and gas pressure tap ports.
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.
9. The liquid line shut-off valve can now be opened. Remove
shut-off valve cap. Fully insert hex wrench into the stem
and back out counterclockwise until valve stem just
touches rolled edge (approximately five [5] turns) observ-
ing
WARNING
statement on page 3. See Figure 3.
10. Replace liquid service pressure tap port cap and valve
stem cap. These caps
MUST BE REPLACED
to
prevent leaks. Replace valve stem cap and pressure tap
cap finger tight, then tighten an additional 1/6 turn.
11. The gas valve can now be opened. Open the gas valve by
removing the shut-off valve cap and turning the valve
stem 1/4 turn counterclockwise, using 1/4" Open End or
Adjustable wrench. See Figure 4.
12. The gas valve is now open for refrigerant flow. Replace
valve stem cap to prevent leaks. Again, these caps
MUST BE REPLACED
to prevent leaks. Replace valve
stem cap and pressure tap cap finger tight, then tighten
an additional 1/6 turn. See Figure 4.
If refrigerant lines are longer than 15 feet and/or a
different size than recommended, it will be necessary to
LIQUID LINE SERVICE VALVE
3
CAP
1/4 TURN ONLY
COUNTERCLOCKWISE
FOR FULL OPEN
POSITION
VALVE STEM
GAS LINE CONNECTION
UNIT SIDE
OF VALVE
CAP
BODY
COOLING
CORE
PRESSURE TAP PORT
GAS LINE SERVICE VALVE
4
