290982-UIM-C-0907
Unitary Products Group
3
PIPING CONNECTIONS
The outdoor condensing unit must be connected to the indoor evapora-
tor coil using field supplied refrigerant grade (ACR) copper tubing that is
internally clean and dry. Units should be installed only with the tubing
sizes for approved system combinations as specified in tabular data
sheet. The charge given is applicable for total tubing lengths up to 15
feet. See Application Data Part Number 247077 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 insufficient 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 structure.
4.
The vapor line must be insulated with a minimum of 1/2" foam rub-
ber insulation (Armaflex or equivalent). Liquid lines that will be
exposed to direct sunlight, high temperatures, or excessive humid-
ity must also be insulated.
5.
Tape and suspend the refrigerant lines as shown. DO NOT allow
tube metal-to-metal contact. See Figure 2.
6.
Use PVC piping as a conduit for all underground installations as
shown in Figure 3. 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 shutdown
7.
Pack fiberglass insulation and a sealing material such as perma-
gum around refrigerant lines where they penetrate a wall to reduce
vibration and to retain some flexibility.
8.
For systems with total line length exceeding 50 feet, see APPLI-
CATION DATA and worksheet "General Piping Recommendations
and Refrigerant Line Length" for vapor and liquid line sizing, cali-
bration of liquid line pressure loss or gain, determination of vapor
line velocity, elevation limitations, orifice connections, system
charging, traps, etc.
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 reusable 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 reusable service valves are pro-
vided to evacuate and charge per this instruction.
Serious service problems can be avoided by taking adequate precau-
tions to assure an internally clean and dry system.
PRECAUTIONS DURING BRAZING SERVICE VALVE
Precautions should be taken to prevent heat damage to service valve
by wrapping a wet rag around it as shown in Figure 4. Also, protect all
painted surfaces, insulation, and plastic base during brazing. After braz-
ing, 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 the chamfered retaining wall.
Connect the refrigerant lines using the following procedure:
1.
Remove the cap and Schrader core from both the liquid and vapor
service valve service ports at the outdoor unit. Connect low pres-
sure 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 con-
tinue flowing.
3.
Carefully remove the plugs from the evaporator liquid and vapor
connections at the indoor coil.
FIGURE 2:
Installation of Vapor Line
Liquid
Line
Incorrect
Correct
Tape
Sheet Metal Hanger
Insulated Vapor Line
FIGURE 3:
Underground Installation
Dry nitrogen should always be supplied through the tubing while it
is being brazed, because the temperature required is high enough
to cause oxidation of the copper unless an inert atmosphere is pro-
vided. 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 necessary 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 chamfered retaining wall,
the O-ring can be damaged causing leakage or system pressure
could force the valve stem out of the valve body possibly causing
personal injury.
TO INDOOR COIL
Liquid Line
PVC
Conduit
Insulated
Vapor Line
TO OUTDOOR UNIT
Cap
