superheat on a rack

[dirtyboy103us]

OK here where are with the argument on superheat
we have a couple of opinions on setting low temp and med. temp
my research has me with 3-5 on low temp and 6-8 on med.
but with the length on the runs on some of these cases
its clear that bringing the med. temp closer to low temp
superheat to help with cool suction gas for the life of the
compressor's would it help to be at 3-5 superheat on med.temp
any ideas on this i know what the books say but has any body tried this

[jeep6275]

if your suction lines are insulated correctly their should be no reason to run extremely low super heats. it will just cause problems later.

[condenseddave]

Jerry hit it.

And, I HOPE you're referring to the superheat at the evaps and not the rack.

You'll be flooding like the French Quarter if you're trying to hold even 8 degrees at the header.

[-frozen-ocean-]

isn't it good pratice to have your epr wide open then take your superheat at your evaporator? usually from there u may add whatever your pressure drop is in your line is from evap to comp. is that a method u can use? also is it good practice to take subcooling on a rack to find out if u got enough gas,or because of load flutuations and winter controls is that not a good method? please clarify anyone

[condenseddave]

I set superheat at the normal full load of a rack. I NEVER force the rack to do more than it normally would, then set the superheat. That's a guaranteed recipe for high superheat.

You can check the subcooling to check the charge, but, again, like I told you in that other thread, in MOST cases, you'll want to maintain a reasonable receiver level.