Specifications

19InRow Air Cooled RD Installation
Mechanical Connections
Refrigeration piping
The equipment must be connected to a condenser—either a remote outdoor condenser or an indoor
centrifugal condenser. Systems with remote outdoor or indoor centrifugal condensers will require
discharge and liquid lines from the equipment to the condenser. Install all refrigerant lines in accordance
with applicable industry guidelines as well as local and national codes and regulations.
To size lines, see “Recommended line sizes” on page 20.
Calculate an equivalent length based on the actual linear length of the run, including valves and fittings.
Note: All fittings should be long-radius to minimize pressure drop.
Discharge lines are sized such that velocity in vertical lines is between 5 m/s (1000 ft/min) and 15 m/s
(3000 ft/m). Limit the velocity in horizontal lines to 2.5 m/s (500 ft/min). The refrigerant velocity must
be high enough to keep oil entrained in the flow. If it is too low, oil will not return to the compressor. If
the refrigerant velocity is too high, both the noise level and pressure drop will increase. Pressure drops of
up to 0.7 bar (10 psi) in discharge lines are acceptable.
Note: Fully loaded, the nominal cooling capacity of the equipment is 10 kW. At its lowest
speed, the equipment cooling capacity is approximately 2 kW.
Note: Give consideration to the loaded and unloaded state of the compressor to ensure that
the operational range stays within these limits.
Note: Change the size of the pipe before the P-trap. See “Refrigeration Piping Diagram” on
page 11.
Make all refrigerant lines as short and direct as possible. Horizontal discharge lines must a minimum
downward pitch of 4 mm per m (1/2 in per 10 ft) in the flow direction to aid in oil return. Install traps in
the vertical discharge lines approximately every 6 m (20 ft) to ensure proper oil return. Traps are
normally not necessary at the base of discharge lines; however, loop the line to the floor before running it
vertically to prevent the drainage of oil back to the compressor during shutdown periods.
Isolate piping from structural surfaces using vibration clamps.
Note: Install all piping in accordance with applicable industry guidelines as well as local and
national codes and regulations.
ASHRAE standards for equivalent piping lengths of fittings and valves
Type of fitting or valve—Equivalent length of pipe in m (ft)
ACR pipe
size, OD
Gate valve Standard
elbow 90°
Reduced
coupling
Side outlet T Angle valve
1/2 in 0.18 (0.6) 0.43 (1.4) 0.43 (1.4) 0.82 (2.7) 1.83 (6.0)
5/8 in 0.21 (0.7) 0.49 (1.6) 0.49 (1.6) 0.91 (3.0) 2.13 (7.0)