Instruction manual
Page 10                   IM-5WMF(SEER13)-0706 
Refrigerant Tubing 
Tubing Length & Elevation 
Copper tubing to connect the indoor and outdoor units is 
supplied by others or it can be ordered from the factory. 
See Table 1 for requirements. Cover both tubes individually 
with 3/8” wall foam insulation. 
Table 1. Refrigeration Tubing Requirements 
Model  10 15 20 25 
Maximum length, ft., L 
40 40 50 50 
Max. elevation, ft., H 
16 16 26 26 
Max. number of bends 
10 10 10 10 
Liquid tube size – OD 
¼” ¼” ¼” ¼” 
Gas tube size - OD 
3/8” ½”  ½” 5/8” 
Note: The refrigerant pre-charged in the outdoor unit is for tubing length up 
to 25ft. See Table 5, page 18 for additional R410A refrigerant required on 
longer runs. 
Figure 10. Tubing Length and Elevation 
Tubing Preparation 
• Do not use contaminated or damaged copper tubing. Do 
not remove plastic, rubber plugs and brass nuts from the 
valves, fittings, tubings and coils until you are ready to 
connect suction or liquid line into valves or fittings. 
• If any brazing work is required, ensure that the nitrogen 
gas is passed through coil and joints while the brazing 
work is done. This will eliminate soot formation on the 
inside wall of the copper tubing. 
•  Cut the copper tubing with a tube cutter. See Figure 11. 
• Remove burrs from cut ends by holding tubing 
downwards to prevent metal chips from entering the 
tubing. 
• Slide the flare nuts, for both the indoor unit and outdoor 
unit onto the copper tubing. 
• Flare the tubing as shown in Figure 11, Figure 12 and 
Table 2. 
•  The flare must be even and not cracked or scratched. 
Figure 11. Cutting and Flaring Tube 
Table 2: Tube Flaring Dimensions 
Tube Diameter - OD X (in.) 
Inch Imperial Rigid 
¼ .051 .028 
3/8 .063 .039 
½ .075 .051 
5/8 .087 .067 
Tubing Connection To Units 
• 
Connect the copper tubing to both the indoor and 
outdoor units. See Figure 12.
• 
Torque each flare nut to specifications. See Table 3. 
•  Cover both tubes individually with 3/8” minimum wall 
foam insulation. 
Table: Flare Nut Torque Specifications 
Tube Size (in.)  Torque (ft./lb.) 
¼ 13.3 
3/8 31.0 
½ 40.6 
5/8 48.0 
Figure 12. Flare Tubing Connections 
H L 
Outdoor Unit 










