515.28-N3Y
5
Unitary Products Group
5.
Use PVC piping as a conduit for all underground installa-
tions as shown in Figure 4. Buried lines should be kept
as short as possible to minimize the build up of liquid
refrigerant in the vapor line during long periods of shut-
down
6.
Pack fiber glass insulation and a sealing material such
as permagum around refrigerant lines where they pen-
etrate a wall to reduce vibration and to retain some
flexibility.
7.
See Form 690.01-AD1V for additional piping informa-
tion..
PRECAUTIONS DURING BRAZING OF LINES
All outdoor unit and evaporator coil connections are copper-
to-copper and should be brazed with a phosphorous-copper
alloy material such as Silfos-5 or equivalent. DO NOT use
soft solder. The outdoor units have re-usable service valves
on both the liquid and vapor connections. The total system
refrigerant charge is retained within the outdoor unit during
shipping and installation. The re-usable service valves are
provided to evacuate and charge per this instruction.
Serious service problems can be avoided by taking adequate
precautions to assure an internally clean and dry system..
PRECAUTIONS DURING BRAZING ANGLE VALVE
Precautions should be taken to prevent heat damage to
angle valve by wrapping a wet rag around it as shown in Fig-
ure 5. Also, protect all painted surfaces and insulation during
brazing. After brazing - cool joint with wet rag.
Valve can be opened by removing the plunger cap and fully
inserting a hex wrench into the stem and backing out counter-
clockwise until valve stem just touches retaining ring.
Replace plunger cap finger tight, then tighten an additional
1/12 turn (1/2 hex flat). Cap must be replaced to prevent
leaks.
Connect the refrigerant lines using the following procedure:
1.
Remove the cap and Schrader core from both the liquid
and vapor angle valve service ports at the outdoor unit.
Connect low pressure nitrogen to the liquid line service
port.
2.
Braze the liquid line to the liquid valve at the outdoor
unit. Be sure to wrap the valve body with a wet rag. Allow
the nitrogen to continue flowing.
FIGURE 3 : TUBING HANGER
FIGURE 4 : UNDERGROUND INSTALLATION
Dry nitrogen should always be supplied through the
tubing while it is being brazed, because the tempera-
ture required is high enough to cause oxidation of the
copper unless an inert atmosphere is provided. The
flow of dry nitrogen should continue until the joint has
cooled. Always use a pressure regulator and safety
valve to insure that only low pressure dry nitrogen is
introduced into the tubing. Only a small flow is neces-
sary to displace air and prevent oxidation.
This is not a backseating valve. The service access
port has a valve core. Opening or closing valve does
not close service access port.
If the valve stem is backed out past the retaining ring,
the O-ring can be damaged causing leakage or sys-
tem pressure could force the valve stem out of the
valve body possibly causing personal injury. In the
event the retaining ring is missing, do not attempt to
open the valve.
