106
SERVICE HANDBOOK
Capillary Tube Sizing
Suggested Capillary Tube Data for Domestic and Commercial Refrigeration
Applications
The following suggestions listed in Table A-1 and the correction factors listed in Table A-2
assume a 115°F liquid temperature, no subcooling prior to the heat exchanger, and 3 ft of
heat exchange with the suction line.
Capillary tube capacity data was generated using the Wolf and Pate 2002 correlation
(ASHRAE Research Project, RP-948)
Example No. 1
Select the capillary required for a Tecumseh R-22 compressor model AEA5460EXA rated
at 6,000 Btu/h at 45°F evaporator. Table A-1, we find 13 ft length of 0.064 in capillary tube.
Example No. 2
Select the capillary required for a Tecumseh R-134a compressor model AJA7461YXA rated
at 6,110 Btu/h at 20°F evaporator. From Table A-1, we find 9 ft length of 0.052 in capillary
tube, 2 required piped in parallel.
Table A-1: Capillary tube selections assume a 115°F liquid temperature and 3
ft of heat exchange length
Capillary Tube, Length - OD
Evaporator Temperature, °F
Refrigerant Btu/h per circuit -10 20 45
22
500 19 ft - 0.026" 18 ft - 0.026" 17 ft - 0.026"
750 12 ft - 0.028" 11 ft - 0.028" 10 ft - 0.028"
1,000 11 ft - 0.031" 10 ft - 0.031" 10 ft - 0.031"
1,250 16 ft - 0.036" 15 ft - 0.036" 15 ft - 0.036"
1,500 11 ft - 0.036" 10 ft - 0.036" 10 ft - 0.036"
2,000 14 ft - 0.042" 13 ft - 0.042" 13 ft - 0.042"
3,000 19 ft - 0.052" 18 ft - 0.052" 18 ft - 0.052"
4,000 10 ft - 0.052" 10 ft - 0.052" 9 ft - 0.052"
6,000 14 ft - 0.064" 13 ft - 0.064" 13 ft - 0.064"
8,000 10 ft - 0.052" (2) 10 ft - 0.052" (2) 9 ft - 0.052" (2)
10,000 13 ft - 0.059" (2) 12 ft - 0.059" (2) 12 ft - 0.059" (2)
12,000 14 ft - 0.064" (2) 13 ft - 0.064" (2) 13 ft - 0.064" (2)
134a
500 14 ft - 0.028" 14 ft - 0.028" 14 ft - 0.028"
750 10 ft - 0.031" 10 ft - 0.031" 10 ft - 0.031"
1,000 12 ft - 0.036" 12 ft - 0.036" 12 ft - 0.036"
1,250 18 ft - 0.042" 18 ft - 0.042" 18 ft - 0.042"
1,500 12 ft - 0.042" 12 ft - 0.042" 12 ft - 0.042"
2,000 22 ft - 0.052" 22 ft - 0.052" 22 ft - 0.052"
3,000 9 ft - 0.052" 9 ft - 0.052" 9 ft - 0.052"
4,000 10 ft - 0.059" 10 ft - 0.059" 10 ft - 0.059"
6,000 9 ft - 0.052" (2) 9 ft - 0.052" (2) 9 ft - 0.052" (2)
8,000 10 ft - 0.059" (2) 10 ft - 0.059" (2) 10 ft - 0.059" (2)
10,000 10 ft - 0.064" (2) 10 ft - 0.064" (2) 10 ft - 0.064" (2)
12,000 10 ft - 0.059" (3) 10 ft - 0.059" (3) 10 ft - 0.059" (3)