Originally posted by JohnFish
Hi guys. Sorry for the naive questions but now that I have built my own chiller I start understand some thing better so I have some questions.

1) How much should the low-side pressure before I have too much refrigerant inside?
2) When we say that there is a vacuum in the low-side or that the low-side 7" or 8" or whatever Hg what does that mean?
3) Should we charge a system by just watching the evap temp (or the frost on the evap) or with the low-side pressure?

Thats it. Thanks in advance
1) ??? Depends upon design temperatures.
2) A vacume is just that a vacume. When we say 4 " hg that is a refrence for below atmosphere. Using a mecury (hg) manometer (Basically a tube sealed at one end filled with mecury adn flipped upside down) at sealevel we would have 0 psi actual barametric pressure is also read in inches of mecury so if we have 30 inches that is atmospheric pressure.
3) None of the abouve charge to a refrence value Like 4 " hg and then add or remove refrigerant as nessassary depending upon superheat Shoot for 10 to 12 a few inches from the evaporator.