Engineering Manual

INSTALLATION & LAYOUT BEST PRACTICES
Refrigerant Piping System Layout
Brazing Practices
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.
• Use a tubing cutter; De-burr and clean all cuts before assembly.
• Do not use flux, soft solder, or anti-oxidant agents.
• Do not use a saw to cut pipe.
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
Pressure-reducing
Valve
Packless
Valve
Tape
Nitrogen
Pipe to
be brazed
Refrigerant
Piping
Figure 282: Refrigerant Pipe Brazing.
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Flare Connection Practices
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 51 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.
Indoor Unit
Piping
Field-Supplied
Piping
Flare Nut
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Piping O.D. (in.) Torque (lbs. / ft.)
1/4 13-18
3/8 24.6-30.4
1/2 39.8-47.7
5/8 45.6-59.3
3/4 71.6-87.5
Indoor Unit Piping
Flare Nut
Field-Supplied
Piping
Figure 283: Flare Connection, Isometric View.
Figure 284: Flare Connection, Side View.
Table 121: Torque Wrench Tightening.
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direction for tightening follows the arrow on the wrench.
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DESIGN & PRACTICES | 203
Refrigerant Piping Design and Best Practices
MULTI
F
MAX
MULTI
F