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2.5 Piping Considerations
The Liebert Mini-Mate2, Liebert DataMate and the 3-ton Liebert Challenger 3000 split system units
are designed with quick-connect fittings and are factory-charged to proper refrigerant levels. This
permits connecting units without brazing inside critical spaces. These split systems require two
refrigerant lines—an insulated copper suction line and a copper liquid line—between the evaporator
and condensing units. The 8-ton Liebert Mini-Mate2 split system units will require four refrigerant
lines between the evaporator and condensing units. Each refrigeration circuit will need one insulated
copper suction line and one copper liquid line.
Two methods exist for installing the copper suction and liquid lines:
• Using optional pre-charged line sets (for 1- to 3.5-ton R-407C model units only).
• Using optional Sweat Adapter Kit(s) and hard piping between units.
NOTICE
Risk of improper handling of refrigerant. Can cause environmental damage and violation of
environmental regulations.
Refrigerant must handled in accordance with all national, regional and local codes.
2.5.1 Piping for Elevation Differences between PFH and Evaporator
System sizes affect the maximum equivalent piping lengths and maximum relative elevation differ-
ences between evaporator and condensing unit mounting locations. See Table 5 for requirements.
Traps in refrigerant piping are required when elevation differences exist between evaporator and con-
densing unit mounting locations. See Figure 12 for requirements. Table 6 should be used when
traps are required with field-fabricated piping assemblies, to calculate equivalent pipe lengths to
determine if installation will comply with Table 5 requirements.
NOTE
Proper safety equipment and proper refrigeration tools are required in working with R-407C
refrigerant. Check unit serial tag for correct refrigerant type before topping off or recharging a
system.
NOTE
Refrigerant R-407C uses a POE (polyol ester) lubricant. The R-407C refrigerant must be
introduced and charged from the cylinder only as a liquid.
NOTE
When installing field piping, care must be taken to protect all refrigerant lines from the
atmosphere, especially when using refrigerants with POE oils. Do not allow the piping to stand
open to air for more than 15 minutes. Units designed for R-407C have a compressor which
contains POE oil that is very hygroscopic; that is, it quickly absorbs water from the air. The
longer the compressor piping is left open to air, the harder it will be to fully evacuate. If left
open too long, the POE oil may need to be replaced before achieving the required vacuum level.
NOTE
Complete all piping and evacuate lines before connecting quick connects when using an
optional sweat adapter kit and field installed hard piping.
Follow all proper brazing practices including a dry nitrogen purge to maintain system
cleanliness.