LOKRING Installation Guide

Table of Contents

Installing LOKRING Tube Connectors

LOKRING Tube Connectors are designed for connecting tubes that have a maximum wall thickness of 1/16 inch. LOKRING Tube Connectors have been tested and approved for use in refrigeration, air conditioning and automotive applications. For use in other applications, please contact American LOKRING Corporation.

LOKRING Tube Connectors are designed for a maximum nominal operating pressure of Pn = 50 bar (750 psi) and a testing pressure of Pp = 4 x Pn = 200 bar (3000 psi). They can be used within a temperature range from -50°C to +150°C (-58°F to +302°F). Burst tests have shown that the LOKRING Tube Connector is stronger than the burst strength of the tube, and are vibration resistant.

To prevent an electrolytic reaction between aluminum and brass, always use an aluminum connector with an aluminum tube. For copper and steel tubes, use brass connectors.

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Assembly of a LOKRING Tube Connection with an Internal Stop for a Capillary Tube

Prepare the tube ends to be joined

The tube ends must be clean and free of burrs and should be straight for at least 30 mm (1-3/16".) Paint, grit, oil and grease must be removed with a suitable medium (emery or 3M Scotch-Brite works well). Clean the tube ends in a rotary direction, not in a longitudinal direction.

Apply LOKPREP

Pull the capillary tube about 10 mm (3/8") out of the LOKRING Tube Connector and apply LOKPREP.

PLEASE NOTE — To prevent capillary tubes from becoming blocked, use only a small amount of LOKPREP.

Assemble the LOKRING connection

Push the capillary tubes back into the LOKRING Tube Connector, up to the stop, and rotate the LOKRING Tube Connector 360° for an even distribution of LOKPREP.

Finished Assembly

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Assembly of a LOKRING Reducing Tube Connector (w/o an Internal Stop)

Prepare the tube ends to be joined

The tubes must be clean and free of burrs. Capillary tubes must be straight for at least 50 mm (2"). Paint, grit, oil and grease must be removed with a suitable medium (emery or 3M Scotch-Brite works well). Clean the tube ends in a rotary direction, not in a longitudinal direction.

Assembly -- Capillary Tube Side

1. Slip the capillary tube all the way through LOKRING reducing connector until the tube extends about 20 mm (3/4") beyond the other end of the connector.

2. Bend the capillary tube slightly behind the LOKRING reducing connector.

Assembly -- Larger Tube Side

1. Apply LOKPREP to the outer surface of the second tube and insert it into the LOKRING reducing connector so that the capillary tube end extends into the larger tube.

2. Insert the larger tube into the LOKRING connector until it meets the internal stop of the connector. Be sure to hold the capillary tube in place.

3. Back the capillary tube out of the LOKRING reducing connector about 10 mm (3/8") and apply a drop of LOKPREP behind the connector.

4. Push the capillary tube back into the LOKRING Reducing Tube Connector up to the bend.

5. Rotate the connector 360° to distribute the LOKPREP evenly on both tubes. Because the capillary tube extends through the LOKRING Tube Connector and into the other tube, blockage is never a problem.

Finish assembly with the assembly tool

Place the LOKRING Connector with tubes in place in the jaws of the assembly tools and draw the rings to the center stop. The LOKRING connection is complete.

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Assembly of a NTR Connector

(Reducer Tee)

The LOKRING NTR Connector allows the repair of a capillary tube inlet in a suction line. In the case of leaks or cracks in the capillary tube, a quick, clean and reliable repair is possible, connecting the copper suction line, the aluminum evaporator tube and capillary tube.

1. Cut suction line and capillary tube.

2. Cut the aluminum suction line to allow approximately 60 mm (2 3/8") of the capillary tube to protrude.

3. Cut suction line and capillary tube.

4. Prepare the tube ends to be joined. The tubes must be clean and free of burrs; the capillary tube must be clean and free of oil. Paint, grit, oil and grease must be removed with emery or 3M Scotch-Brite pad. The tube ends should be cleaned in a rotary direction, not in a longitudinal direction.

When connecting a tube to the side leg of a Tee, insert the NTR Adapter into the assembly jaws to support the crosspiece.

Apply LOKPREP to the suction line and the capillary tube where the tube connection will be assembled. LOKPREP must not get to the end of the capillary tube (danger of blockage).

6. Push NTR connector over capillary tube and suction line up to the stop and rotate 360° for better distribution of LOKPREP.

7. Compress the connector using the assembly tool until the rings reach the center stop.

8. Insert the copper suction line 3 mm (1/8") into the tee side leg and run a thin film of LOKPREP around the tube. Fully insert the copper tube into the connector. Fit the NTR tool-insert into the assembly jaw of the handtool.

9. Set the connector into the jaws of the handtool so that the back of the tee is positioned in the tool insert. Compress the connector.

10. Reconnect the capillary tube using a LOKRING capillary connector.

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Assembly of a NAV Connection
to Extend Compressor Stubs

In order to join a tube to a compressor stub using a LOKRING Tube Connector, a stub length of at least 20 mm (3/4") is required. To extend shorter compressor stubs, use a NAV connection.

1. The compressor stub should not be longer than the flare of the NAV connection and not shorter than the length of the LOKRING +2 mm (3/32") which is used. Paint, grit, oil and grease must be removed with a suitable medium (emery or 3M Scotch-Brite works well) and the tube ends should be cleaned in a rotary direction.

2. Apply LOKPREP to the compressor stub and push on the NAV connector.

3. Drive on the LOKRING up to the compressor casing with of the NAV assembly tool and a hammer.

4. Connect the compressor using LOKRING Tube Connectors.

Extension Fitting

A flared copper tube is fitted over the stub end and a Single-Ring LOKRING is hammered over the tube to complete the extension.

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