PMGB0374
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6. Refrigerant Piping Work
6.1 Piping Materials
(1) Tolerances for refrigerant piping lengths depend on the combinations with the outdoor unit. Refer to the
“Installation and Maintenance Manual” for the outdoor unit for details.
(2) Select the piping size from Section 6.2 "Piping Connection".
(3) Prepare the field-supplied copper piping.
(4) Select clean copper pipes. Make sure there is no dust or moisture inside.
(5) The refrigerant oil used in combinations with refrigerant R410A is susceptible to problems relating to
moisture contamination, oxide film, oil, and fat. Exercise special care during the installation so that
moisture, particulate contamination, or old refrigerant oil will not enter the refrigerant system. Otherwise,
impurities may adhere to the expansion valve and it may prevent proper operation.
(6) Caution: When cutting piping, do not use conventional tools such as saws or grinding wheel cutting
disks that produce harmful metallic filings that can damage a refrigerant system. Use a pipe cutter to
eliminate the chances of metal filings produced by the cutting operation. After the cut is made, blow out
each pipe with dry compressed air or nitrogen to remove any residue before making pipe connections.
For details on refrigerant piping work, vacuum pump, and refrigerant charge, refer to the "Installation and
Maintenance Manual" for the outdoor unit.
Use the specified non-flammable refrigerant (HFC R410A) for the outdoor unit refrigerant system. Do
not charge the unit with anything other than HFC R410A, such as hydrocarbon refrigerants (propane
and isobutene), oxygen, and other flammable gases (acetylene, ammonia, and so forth), or any
poisonous gases when installing, maintaining and moving the unit. These substances are volatile
and dangerous and can result in fire, explosion, and serious or fatal injuries.
When Placing the Pipe
Through a Hole in the Wall
Correct
Correct
Incorrect
Incorrect
Correct
Incorrect
Hole
Hole
Attach a cap or put a plastic bag
over the pipe end.
Attach a cap or put a plastic
bag over the pipe end.
Attach a cap or put a plastic
bag over the pipe end.
Rubber Band
Do not lay the pipe
directly on the ground.
Rain water
can come in.
In Case of Rain
