LG MULTI F Engineering Manual page 207

F
MULTI
F
MULTI MAX
Brazing Practices
Keep the piping system free of contaminants and debris such copper burrs, slag, or carbon dust during installation.
1. All joints are brazed in the field. Multi F refrigeration system components
contain very small capillary tubes, small orifices, electronic expansion valves,
oil separators, and heat exchangers that can easily become blocked.
• Store pipe stock in a dry place; keep stored pipe capped and clean.
• Blow clean all pipe sections with dry nitrogen before assembly.
2. Proper system operation depends on the installer using best practices and
utmost care while assembling the piping system.
• Use adapters to assemble different sizes of pipe.
• Do not use flux, soft solder, or anti-oxidant agents.
• Use a tubing cutter; do not use a saw to cut pipe. De-burr and clean all cuts before assembly.
3. Brazing Joints:
• Use a dry nitrogen purge operating at a minimum pressure of three (3) psig and maintain a steady flow.
• Use a 15% silver phosphorous copper brazing alloy to avoid overheating and produce good flow.
• Protect isolation valves, electronic expansion valves, and other heat-sensitive control components from excessive heat with a wet rag or a
heat barrier spray product
Flare Connection Practices
Improperly installed flare connections can lead to refrigerant leaks.
1. Place a couple of drops of refrigerant oil on the opening rim
of the flare before assembling. Take care not to add any
contaminants.
2. Align the center of the refrigerant pipe and corresponding
connection and tighten the flare nut by hand.
3. Following the guidelines as outlined in Table 125 for the amount
of torque to use, tighten the flare nut with a torque wrench until
the wrench clicks.
4. When flare is sufficiently tightened and the system has been
tested for refrigerant leaks, wrap insulation around the
connection.
When tightening the flare unit with a torque wrench, ensure the
direction for tightening follows the arrow on the wrench.
Table 128:Torque Wrench Tightening.
Piping O.D. (in.)
1/4
3/8
1/2
5/8
3/4
INSTALLATION & LAYOUT BEST PRACTICES
Torque (lbs. / ft.)
13-18
24.6-30.4
39.8-47.7
45.6-59.3
71.6-87.5
Due to our policy of continuous product innovation, some specifications may change without notification.
©LG Electronics U.S.A., Inc., Englewood Cliffs, NJ. All rights reserved. "LG" is a registered trademark of LG Corp.
Refrigerant Piping System Layout
Figure 287: Refrigerant Pipe Brazing.
Refrigerant
Piping
Figure 288:Flare Connection, Isometric View.
Indoor Unit
Piping
Figure 289:Flare Connection, Side View.
Indoor Unit Piping
Flare Nut Field-Supplied
Figure 290:Using the Torque Wrench.
Wrench
Indoor Unit Piping
Pressure-reducing
Pipe to
be brazed
Nitrogen
Packless
Tape
Valve
Field-Supplied
Piping
Flare Nut
Piping
Open-End Wrench
Flare Nut
Field-Supplied
Piping
DESIGN & PRACTICES | 207
Valve