10
2.0 PIPING
2.1 Split Air Cooled Unit Piping
Refer to the attached Line Sizing chart on page 31 for a guideline for sizing refrigerant lines. The
ultimate responsibility for line size selection is that of the installing contractor or project engineer.
Data Aire does not assume this responsibility. The chart covers distances up to 200 equivalent feet.
For installations beyond this distance, consult ASHRAE or similar references.
Standard Piping practice must be used to ensure proper oil return and effi cient operation.
The interconnecting lines to the remote air cooled condenser must be installed by a
qualifi ed refrigeration mechanic.
2.1.1 Discharge
Lines
Discharge lines, also called Hot Gas lines, should be trapped at the top (inverted) and bottom, as well
as every 20 feet of vertical rise. Discharge line check valves are recommended on all installations,
especially those where there are long pipe runs or cold climate. Check valves should be installed
six feet from the compressor.
Discharge line pressure drop should not exceed 6 PSI. Recommended gas velocity for proper oil
return is 1,000 FPM. Slope horizontal lines downward in the direction of refrigerant fl ow 1/2” for
every ten feet of line length.
2.1.2 Liquid
Lines
Liquid line size is determined by pressure drop and velocity. The liquid line pressure drop should be
not exceed 5 PSI. The recommended velocity should be between 200 and 300 FPM.
To avoid excessive liquid line pressure drop, the air cooled condenser should be located above or at
the same level as the evaporator. Condenser installation more than ten feet below the evaporator
should be avoided.
2.1.3 Suction
Lines
Some applications call for the compressor to be mounted in the outdoor condenser, or condensing
unit. Such cases require fi eld piping of liquid and suction lines. Suction lines are trapped similarly
to discharge lines except for the inverted trap at the top of the suction line and the line needs to be
insulated with a minimum 1/2” thick insulation or per code. Common practice for suction line selection,
see page
31
, and installation should be followed.
2.1.4 Connection Sizes, Air Cooled Units
Model Hot
Gas
Liquid
Suction
DAMA 0112
1/2”
1/2”
3/4”
Note: Unit will have a Liquid Line and
DAMA 1.512
1/2”
1/2”
3/4”
either a Hot Gas or Suction Line
DAMA
0212
1/2” 1/2” 3/4”
DAMA
2.512
1/2” 1/2” 3/4”
Field connections at the indoor evaporator and remote condenser or condensing unit will
not necessarily be the same as the fi eld pipe size required. In some cases these will
