What precautions should one take while installing long refrigerant lines- DX- R 410 A refrigerant.
Case 1. Compressor above indoor coil -Horizontal 100 feet equivalent plus vertical 15 ft equivalent
Case 2. Compressor above indoor coil- Horizontal 15 feet equiv plus vertical 100 ft equivalent.
Case 3. Same as case 1 but compressor below.
Case 4. Same as case 2 but compressor below.

Personal safety is always of utmost importance
When working on any HVAC system. Safety glasses and
Gloves should be worn regardless of the refrigerant being
Used. If it is necessary to heat a cylinder of R-410A—to
Raise its pressure in cooler weather—heat the cylinder with
Water that is 90°F or lower; never heat a cylinder with a
Flame. Don't allow the cylinder to reach a temperature of
More than 125°F during transport or storage. As a
Reminder, a cylinder of R-410A at 125°F exerts a cylinder
Pressure of 450 psig. Never exceed 80% of the capacity of a
Recovery cylinder. Doing so may cause the cylinder to rupture,
Causing possible physical injury or property damage.
Recovery cylinders must be Department of Transportation
Rated for R-410A use.
Equipment selection:
Always
Replace linesets in retrofit applications to prevent intermixing
Of the MO or AB oil with the POE oils. If replacing
The linesets is not practical, the following precautions
Should be taken:
• Inspect the linesets for kinks, sharp bends or other
Restrictions, and for corrosion;
• Determine if there are any low spots thatmight serve
As oil traps;
• Flush the linesets with a flush kit (available commercially)
To remove as much of the existing oil and contaminants
As possible; and
• Install a suction line filter-drier to trap any remaining
Contaminants, and remove them after 50 hours of
Operation.
Because R-410A and POE oilmix so well together, oil-trap
Installation is generally not required on R-410A systems.
However, technicians should always be sure to seal refrigerant
Lines by crimping them closed and brazing them if they
Will be exposed to the atmosphere for any length of time.
Never leave refrigeration lines open to the atmosphere to prevent
Moisture and contaminants from entering the system.
When connecting
Lines, techs should not use soft solder. A brazing alloy with
A minimum 5% silver content is recommended. A lowpressure
Flow of dry nitrogen should be used when brazing
Line connections in the field to prevent oxide formation on
The interior walls of the copper tubing. POE lubricants
Used in R-410A systems are a form of a mild organic acid,
Which scrubs oxides and contaminants from the interior
Of refrigerant tubing walls. The oxides, once removed, will
Begin to circulate through the system and will likely end
Up in the metering device and create performance issues.
Once installed, the start-up procedures for an R-410A system
Are identical to those of a traditional R-22 system.
Because of the higher
Pressure and POE oil found in an R-410A system, any tool
Or test instrument that comes in contact with refrigerantlatest coil and condensing unit combination ratings,
visit the Air-Conditioning and Refrigeration Institute
(ARI) at www.aridirectory.org.

Piping design guide>http://www.mcquay.com/mcquaybiz/literature/lit_systems/AppGuide/AG_31-011_120407.pdf