Product data

Refrigerant Lines – 38HDS
1. The 38HDS units are shipped with a full charge of R-22 refrigerant.
2. All charges, line sizes and capacities are based on 25 feet of refrigerant lines. For runs over 25 feet see
Long Line Applications.
3. Filter dryers are provided in the unit.
4. Refrigerant lines should not be buried in the ground. If it is necessary to bury the lines, not more than
36” should be buried. Provide a minimum 6” vertical rise to the service valves to prevent refrigerant
migration.
5. The vapor and liquid lines must be insulated. Use a minimum of ½” thick insulation. Closed cell
insulation is recommended in all long line applications.
6. Special consideration should be given to isolating interconnecting tubing from the building structure.
Isolate the tubing so that vibration or noise is not transmitted into the structure.
Long Line Applications
1. Two phase supply lines should be 3/8” only. DO NOT resize liquid lines for additional length.
2. When sizing the 5/8” vapor line, determine line length by finding equivalent feet of pipe. Equivalent
line lengths equal the linear length (measured length) of interconnecting vapor tubing plus losses due
to elbows (see Fitting Loss in Equivalent Feet for Elbows Table #2) If the number of elbows is not yet
known, assume 50% additional length for the equivalent length. In determining line size, be sure oil
can be properly returned to the compressor. Consult the Carrier Systems Design Guide for proper oil
return recommendations. For line lengths from 25 to 49 feet no special piping requirements are
normally required.
For line lengths over 25 feet
3. Due to the TXV valve a liquid line solenoid is not required for vertical lift applications over 25 feet.
a. Horizontal configuration Diagram #1
1. Slope the vapor line toward the indoor unit to provide for refrigerant migration protection
during the off cycle due to temperature differences caused by slight elevation changes
between indoor and outdoor units.
b. Elevated configuration: (Lift) Indoor unit above outdoor unit Diagram #3
1. The maximum elevation difference is 30 feet and the maximum equivalent length of piping is
50 feet.
2. Install an inverted trap in the vapor line. The top of the trap must be above the top of the
indoor unit. This prevents the refrigeration from collecting in the vapor line.
c. Lowered configuration: (Drop) Indoor unit below outdoor unit Diagram #4
1. The maximum elevation difference is 30 feet and the maximum equivalent length of piping is
50 feet.
2. Additional Charge: Due to the TXV valve additional charge should not be required