Johnson Controls AC6B Precautions During Line Installation, Precautions During Brazing of Lines

562156-UIM-A-0610

The outdoor condensing unit must be connected to the indoor evapora- tor coil using field supplied refrigerant grade copper tubing that is inter- nally 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.

NOTICE

Using a larger than specified line size could result in oil return prob- lems. 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 facili- tate 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 rubber insulation (Armaflex 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 tube metal-to-metal contact. See Figure 2 "Tubing Hanger".

6.Use PVC piping as a conduit for all underground installations as shown in Figure 3 "Underground Installation". 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 permagum around refrigerant lines where they penetrate a wall to reduce vibra- tion and to retain some flexibility.

8.See application part number 247077 for additional piping informa- tion.

SHEET METAL
HANGER
LIQUID
LINE
INCORRECT
	TAPE
CORRECT	INSULATED
	VAPOR LINE
FIGURE 2: Tubing Hanger

TO INDOOR		TO OUTDOOR
COIL
		COIL
LIQUID
	INSULATED
LINE		CAP
	VAPOR LINE
PVC
CONDUIT

FIGURE 3: Underground Installation

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 ensure an internally clean and dry system.

Dry nitrogen should always be supplied through the tubing while it is being brazed, because the temperature 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 necessary to displace air and prevent oxidation.

PRECAUTIONS DURING BRAZING SERVICE VALVE

Precautions should be taken to prevent heat damage to service valves by wrapping a wet rag around it as shown in Figure 4 "Heat Protection". Also, protect all painted surfaces, insulation, and plastic base during brazing. After brazing, cool joint with wet rag.

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.

The valve can be opened by removing the plunger cap and fully insert- ing 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.Refer to the Tabular Data Sheet for proper vapor and liquid line siz- ing.

Do not leave the system open to the atmosphere. Unit damage could occur due to moisture being absorbed by the POE oil in the system. This type of oil is highly susceptible to moisture absorp- tion.

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