Vertiv Liebert MC, Инструкция по установке и эксплуатации

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5.1.1 Refrigerant Piping Guidelines for Air-cooled Systems
• Air-cooled units and condensers ship with an inert-gas holding charge. Do not vent the
evaporator until all refrigerant piping is in place, ready for connection to the unit and
condenser
• Use copper piping with a brazing alloy with a minimum temperature of 1350°F (732°C), such as
Sil-Fos. Avoid soft solders, such as 50/50 or 95/5.
• Use a flow of dry nitrogen through the piping during brazing to prevent formation of copper
oxide scale inside the piping. When copper is heated in the presence of air, copper oxide forms.
POE oils will dissolve these oxides from inside the copper pipes and deposit them throughout
the system, clogging filter driers and affecting other system components.
• A pure dry nitrogen flow of 1-3 ft
3
/min (0.5-1.5 l/s) inside the pipe during brazing is sufficient to
displace the air. Control the flow using a suitable measuring device.
• Ensure that the tubing surfaces to be brazed are clean and that all burrs have been removed
from the ends of the tubes.
• Ensure that all loose material has been cleaned from inside the tubing before brazing.
• Protect all refrigerant line components within 18 in. (460 mm) of the brazing site by wrapping
them with a wet cloth or with a suitable heat-sink compound.
• Isolate piping from building using vibration-isolating supports.
• Install traps on hot-gas (discharge) lines at the base of vertical risers over 5 ft (1.5 m) and every
20 ft (6 m) for vertical rises over 25 ft (7.6 m), then install a trap in 20-ft (6-m) increments or
evenly-divided over the vertical rise.
• When connecting to a DA250 indoor unit: Install traps on hot-gas (discharge) lines at the base
of vertical risers over 5 ft (1.5 m) and every 20 ft (6 m) or evenly-divided over the vertical rise.
The DA250 has internally-installed traps on the hot-gas lines.
• Pitch horizontal hot-gas piping down at a minimum rate of 1/2 in. per 10 ft (42 mm per 10 m) so
that gravity will aid in moving oil in the direction of refrigerant/oil flow.
• When connecting to a DA165 indoor unit: Consult factory if piping run exceeds 300 ft (91 m)
actual length or 450 ft (137.2 m) equivalent length.
• Keep piping clean and dry, especially on units with R-410A refrigerant.
• Avoid piping runs through noise-sensitive areas.
• Do not run piping directly in front of discharge air stream.
• Refrigerant oil – do not mix oil types. Consult the indoor-unit installation/user guide for
refrigerant type and oil requirements.
Refer to ASHRAE Refrigeration Handbook for general, good-practice refrigeration piping. The indoor
cooling unit has a factory-installed high-pressure safety switch in the high side refrigerant circuit. A
fusible plug kit is installed in each Liebert MCV receiver.
NOTE: All indoor and outdoor field refrigerant piping must have 1/2 in. minimum of insulation. All
outdoor insulation must be UV and ozone resistant.
Vertiv | Liebert® MCV™ Installer/User Guide | 16