188.8.131.52 Outdoor Unit Below Indoor Coil (Long Line Set Applications)
INSULATED VAPOR LINE FULL LENGTH
For applications with the outdoor unit below the
indoor coil, the following is required:
• Inverted vapor-line trap (Reference Figure 4)
• Insulated liquid line in unconditioned space only.
• Insulated vapor line full length.
• Follow the proper line sizing, maximum linear
and equivalent length, maximum vertical separa-
tion, charging requirements, and oil level adjust-
ments spelled out in this document.
EVEN WITH TOP
OF THE COIL
INSULATE LIQUID LINE
SPACE FOR LONG
VERIFY LIQUID SUBCOOLING
PRIOR TO EXPANSION DEVICE
IN THE COOLING MODE.
REFERENCE TABLE 2 FOR
MAXIMUM LENGTH AND
VERTICAL SEPARATION LIMITATIONS
• Measure pressure at the liquid line service valve
and prior to expansion device. Verify that the
pressure drop is not greater than 50 PSI [345
• For elevations greater that 25' [8 m] a lower sub-
cooling can be expected.
• Verify there is at least 5ºF [2.8ºC] of liquid sub-
cooling at the indoor coil prior to the expansion