18-AC51D3-3
3
Installer’s Guide
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 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 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 HCFC-22 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 HCFC-22 cylinder and charge refrigerant lines
and indoor coil with vapor to tank pressure of HCFC-22
supply.
NOTE:
DO NOT VENT REFRIGERANT INTO THE ATMOSPHERE.
8. Close valve on HCFC-22 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 backout counterclockwise until valve stem just touches
LIQUID LINE SERVICE VALVE
4
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 BALL SERVICE VALVE
5
GAS LINE SERVICE VALVE
