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system is completed and sealed.
Data Aire recommends a silver/phosphorus/copper alloy with 5 to 15% silver be used to braze
the refrigerant line sets to the indoor and outdoor units. Nitrogen needs to be flowing through
the lines to eliminate carbon deposit build-up on the inside of the joints. Carbon could
contaminate the refrigerant and restrict the metering device.
Piping must be supported within 18” (457 mm) of the inlet and outlet connections external to
the unit. Internal to the unit, the inlet connection is located on the top header of all units. The
discharge outlet is located at the bottom of the header.
Discharge line pressure drop should not exceed 9 PSI (62 kPa) for R-410A. Recommended
gas velocity for proper oil return is 1,000 FPM (5.1 m/sec). Slope horizontal lines downward in
the direction of the refrigerant flow. The recommended slope is 1/2” (12 mm) for every ten (10)
feet (3 m) of line length. Discharge lines do not require insulation but due to the high
temperatures of the refrigerant inside the line, the pipes may be insulated to protect against
burns to individuals near or around the lines.
Liquid Lines
Liquid line size is determined by pressure drop and velocity. The liquid line pressure drop
should not exceed 9 PSI (62 kPa) for R-410A. The recommended liquid velocity should be
between 200 and 300 FPM (1 to 1.5 m/sec). To avoid excessive liquid line pressure drop, the
air-cooled condenser should be located above or at the same level as the evaporator.
Condenser installations more than 15 feet (4.6 m) below the evaporator are not recommended.
Insulation of liquid lines is not required but can be useful in preventing excessive sub-cooling
or flashing on long exposed pipe runs.
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