oil Return for R410a

[mac_J]

Would like to know what is the limit on the length of a vertical riser for the suction line, size 1.1/8 (Inch and one eighth) on a 410a installation. Capacity of system 12 kW, evaporating @ -5C, condensing @45C. What trapping arrangements is needed to insure proper oil return. All help appreciated.

[mad fridgie]

Would like to know what is the limit on the length of a vertical riser for the suction line, size 1.1/8 (Inch and one eighth) on a 410a installation. Capacity of system 12 kW, evaporating @ -5C, condensing @45C. What trapping arrangements is needed to insure proper oil return. All help appreciated.

I would say that your suction line is way to big for this duty, I would choose 3/4" and a trap every 3-4 meters

[lana]

You did not mention the length of the pipe both horizontal and vertical.

For 20 m run you need 7/8" suction tube. If you give exact number of fittings and length then I can give you the exact tube size.
About the vertical riser : If you use correct pipe size then only you need oil traps. Depending on your tube size you have to install oil traps every few meters. For example for 7/8" tube every 5 m is OK. There is no formula to calculate the traps distance. The bigger the diameter then more oil is on the tube walls.
Cheers