Piping Height Requirements
The system piping layout must take in the constraints of vertical height on system performance.
The outdoor unit has a vertical height limit in which it can properly circulate refrigerant in the system.
INDOOR UNIT INSTALLATION
Capacity Size (BtuH)
Distance ft (m)
18,000
33 (10)
24,000
33 (10)
30,000
49 (15)
36,000
49 (15)
42,000
49 (15)
Capacity Size (BtuH)
Distance ft (m)
18,000
33 (10)
24,000
33 (10)
30,000
33 (10)
36,000
33 (10)
42,000
33 (10)
The maximum elevation (H1) from the bottom
of the outdoor unit to the bottom of the highest
mounted indoor units must be less than:
The maximum elevation (H2) between those
two indoor units from bottom of one unit to
bottom of the other unit must be less than:
Verify your H1 and H2 maximum elevation measurements are less than the system limits.
L2
L3
...Ln
H1
H2
15
Oil return bend
Indoor
Outdoor
20
ft.
30
ft.
Oil return bend
Oil Return Bend
When the outdoor unit is more than 30 feet above the
indoor unit, an oil return bend must be added for every
20 feet of connection pipe.
PIPING INSTALLATION
3. Apply a small amount of refrigerant oil to the flare connection on the refrigerant pipe.
4. Properly align piping and tighten flare nut using a standard wrench and a torque
wrench as shown in the indoor piping section.
5. Carefully tighten flare nuts to correct torque level referring to the following Torque Table:
NOTE:
Over tightening may damage flare connections and cause leaks.
Pipe Diameter
Nut Size
Tightening Torque
inch (mm)
inch (mm)
ft-lbs
N-m
1/4 (6.35)
1/4 (17)
10 to 13
14 to 18
3/8 (9.5)
3/8 (22)
25 to 30
34 to 42
1/2 (12.7)
1/2 (25)
36 to 45
49 to 61
5/8 (15.9)
5/8 (29)
50 to 60
68 to 82
Torque Table
Piping Connections to Outdoor Unit
(con’t)
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TWD-1518 install_printer.qxp_Layout 1 3/22/17 9:41 AM Page 33