Superheat at the Compressor

[hvactech80]

My Question involves the Total Superheat at the Compressor on a Packaged Liquid Chiller—I have been informed since it is a Packaged unit with a short Piping run—The Superheat will be close to the Coil Superheat of 12---I have been informed in the Past—No less than 20 Degrees Total Superheat at the Compressor—I have been informed—if a Refrigeration Panellist answers this it will be 12 Degrees Total and if a Airconditioning Panellist answers this it will be 20---We have been Setting 8-12 Degrees SH on the Coil and 20 at the Compressor—Thank you for your Time.

[powell]

Check out this old post. You'll find all your answers. Post 35 is from a Copeland guy.

http://hvac-talk.com/vbb/showthread.php?t=161476

[jayguy]

you are a field technician...copeland and every other compressor manufacturer will tell you that you need 20F because you have crap equipment, spend 5 minutes on troubleshooting and you dick with the txv everytime you have a chance...well, maybe not you, but you get the picture.

if you are a manufacturer...then compressor manufacturers will allow you less because you test everything many times over with NIST equipment and then you write it down in the IOM that you need to have 12F suction superheat (or whatever).

that's the difference.

[joey791]

Read the IOM to get the proper superheat setting for whatever piece of equipment. We were turned down by Mcquay for warranty on a compressor on one of their chillers because our start up sheet it was set for 12 degrees and their manual said it should be 8, always check the IOM.