Thermo Products R-410A installation manual Precautions During Brazing of Lines

835961-UIM-D-0213

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.

Dry nitrogen should always be supplied through the tubing while it is being brazed, because the temperature is high enough to cause oxi- dation 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.

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.

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.

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.

FIGURE 4: Heat Protection

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 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. Refer to the Tabular Data Sheet for proper liquid line sizing.

3.Go to “SECTION IV” or “SECTION V” for orifice or TXV Installation depending on application.

Do not install any coil in a furnace which is to be operated during the heating season without attaching the refrigerant lines to the coil. The coil is under 30 to 35 psig inert gas pressure which must be released to prevent excessive pressure build-up and possible coil damage.

4.Braze the liquid line to the evaporator liquid connection. Nitrogen should be flowing through the evaporator coil.

5.Slide the grommet away from the vapor connection at the indoor coil. Braze the vapor line to the evaporator vapor connection. After the connection has cooled, slide the grommet back into original position. Refer to the Tabular Data Sheet for proper vapor line sizing.

6.Protect the vapor valve with a wet rag and braze the vapor line con- nection to the outdoor unit. The nitrogen flow should be exiting the system from the vapor service port connection. After this connection has cooled, remove the nitrogen source from the liquid fitting service port.

7.Replace the Schrader core in the liquid and vapor valves.

8.Leak test all refrigerant piping connections including the service port flare caps to be sure they are leak tight. DO NOT OVERTIGHTEN (between 40 and 60 inch - lbs. maximum).

9.Evacuate the vapor line, evaporator, and the liquid line to 500 microns or less.

NOTICE

Line set and indoor coil can be pressurized to 250 psig with dry nitro- gen and leak tested with a bubble type leak detector. Then release the nitrogen charge.

Do not use the system refrigerant in the outdoor unit to purge or leak test.

10.Replace cap on service ports. Do not remove the flare caps from the service ports except when necessary for servicing the system.

Do not connect manifold gauges unless trouble is suspected. Approx- imately 3/4 ounce of refrigerant will be lost each time a standard man- ifold gauge is connected.

11.Release the refrigerant charge into the system. Open both the liquid and vapor valves by removing the plunger cap and with an allen wrench back out counter-clockwise until valve stem just touches the chamfered retaining wall. If the service valve is a ball valve, use a cresent wrench to turn valve stem one-quarter turn counterclockwise to open. Do not overturn or the valve stem may break or become damaged. See “PRECAUTIONS DURING BRAZING SERVICE VALVE”.

12.Replace plunger cap finger tight, then tighten an additional 1/12 turn (1/2 hex flat). Cap must be replaced to prevent leaks.

Never attempt to repair any brazed connections while the system is under pressure. Personal injury could result.

See "System Charge” section for checking and recording system charge.

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