Refrigerant Piping Work - Mitsubishi Electric PAAA18AA1 Installation Manual

11. Refrigerant piping work

NOTE
For constraints on refrigerant piping lengths and allowable differences in elevation, refer to
the design section of the engineering manual.
For information about maximum total piping lengths for PAA series connections, see "PAA-
series (Cased A-Coil) Connection" in the "Before getting started" section.
The method of pipe connection on the A-Coil is flare connection.
Provide proper bracing for refrigerant piping so no load is imparted upon the connections
at the A-Coil.
WARNING
• Always wear safety glasses when working around pressurized devices.
– Failure to follow safety requirements can results in injury or death or building damage.
CAUTION
• When installing or moving the unit, do not charge it with refrigerant other than the
refrigerant specified on the unit.
– Mixing of a different refrigerant, air, etc. may cause the refrigerant cycle to malfunction
and result in severe damage.
• Use refrigerant piping made of C12200 (Cu-DHP) phosphorus deoxidized copper as
specified in the ASTM B280 Standard Specification for Seamless Copper Tube for Air
Conditioning and Refrigeration Field Service. In addition, be sure that the inner and
outer surfaces of the pipes are clean and free of hazardous sulphur, oxides, dust/dirt,
shaving particles, oils, moisture, or any other contaminant. Never use existing refrigerant
piping.
• The air handlers are shipped with a nitrogen holding charge in the coil. Carefully follow
these instructions when releasing the charge.
– Carefully remove the flare nut off the end of the pipe to release any gas.
– Both refrigerant lines need to be insulated all the way up to the cabinet. Make sure
the openings in the cabinet around the refrigerant lines are sealed. 3/8 inch thick
insulation is the minimum recommended thickness. Based on ambient conditions,
local codes and line length, thicker insulation may be required.
– Do not put any oil on the threaded portion of the flare nuts. This may cause the flare
nut to loosen and leak refrigerant.
© 2022 Mitsubishi Electric US, Inc.
PAA-A18, 24, 30, 36, 42AA1/BA1/CA1
60 Specifications are subject to change without notice.