PIPING CONNECTIONS
The outdoor condensing unit may be connected to the indoor
evaporator coil using field supplied refrigerant grade copper
tubing that is internally clean and dry. Units should be installed
only with the tubing sizes for approved system combinations
as specified in Table 5. The charge given is applicable for total
tubing lengths up to 15 feet. See Application Data Form 690.01-
AD1V for installing tubing of longer lengths and elevation
differences.
NOTE: Using a larger than specified line size could result in
oil return problems. Using too small a line will result in
loss of capacity and other problems caused by insuffi-
cient refrigerant flow. Slope horizontal vapor lines at
least 1" every 20 feet toward the outdoor unit to
facilitate proper oil return.
PRECAUTIONS DURING LINE INSTALLATION
1. Install the lines with as few bends as possible. Care must
be taken not to damage the couplings or kink the tubing.
Use clean hard drawn copper tubing where no appreciable
amount of bending around obstruction is necessary. If soft
copper must be used, care must be taken to avoid sharp
bends which may cause a restriction.
2. The lines should be installed so that they will not obstruct
service access to the coil, air handling system or filter.
3. Care must also be taken to isolate the refrigerant lines to
minimize noise transmission from the equipment to the struc-
ture.
4. The vapor line must be insulated with a minimum of 1/2"
foam rubber insulation (Arm-A-Flex or equivalent). Liquid
lines that will be exposed to direct sunlight and/or high
temperatures must also be insulated.
5. Tape and suspend the refrigerant lines as shown. DO NOT
allow metal-to metal contact. See Figure 4.
6. Use PVC piping as a conduit for all underground installa-
tions as shown in Figure 5. Buried lines should be kept as
short as possible to minimize the build up of liquid refriger-
ant in the vapor line during long periods of shutdown.
7. Pack fiber glass insulation and a sealing material such as
permagum around refrigerant lines where they penetrate a
wall to reduce vibration and to retain some flexibility.
8. See Form 690.01-AD1V for additional piping information.
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.
CAUTION: 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 nec-
essary to displace air and prevent oxidation.
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 Figure 6.
Also, protect all painted surfaces and insulation during brazing.
After brazing - cool joint with wet rag.
WARNING: This is not a backseating valve. The service access
port has a valve core. Opening or closing valve
does not close service access port.
Valve can be opened by removing the plunger cap (See Figure
7) and fully inserting a hex wrench into the stem and backing
out counter-clockwise until valve stem just touches retaining ring.
FIGURE 4 - TUBING HANGER
LIQUID
LINE
TAPE
SHEET
METAL
HANGER
INSULATED
VAPOR LINE
TO INDOOR COIL
TO OUTDOOR UNIT
LIQUID LINE
CAP
PVC
CONDUIT
INSULATED
VAPOR LINE
FIGURE 5 - UNDERGROUND INSTALLATION
550.37-N1Y
4
Central Environmental Systems
