Charge A Chest Freezer

[Karl_T]

Way OT, didn't know where else to ask. Hope there's an HVAC guy out there.


We have a 21 cuft commercial chest freezer. Quit working. My neighbor
was over last night and put on a pierce style fill fitting and put in
a couple oz R134a. Got -27 deg F this morning. So, all unit needs is a
bit of refrigerant.

Pressure reading on low side is -15 in HG. Any educated guess on what
low side pressure i should fill to?

Second question, my neighbor said R134a is a blended refrigerant so you
need to have can upside down to put in liquid. This can be a problem
slugging a small system. On all my R12 and R22 systems I've just let
the compressor suck in vapor off the top. Is it really necessary to
have can upside down?

 

[master53yoda]

Your are really close with the charge right now. a few ounces is all that it holds. Residential style systems are very hard to get the charge correct because they are so small. attached is the site for a temp chart for 134a. http://www.google.com/url?sa=t&rct=...H7zrcCIaD4DfOPA&bvm=bv.94911696,d.cGU&cad=rjt 15HG gives an evap point of -41 so your -27 in the freezer would mean that you are very close to correct. In order to get them right you have to weigh in the charge. The flips side is that you must have a leak in order to be low and it will just quite working again unless you find the leak.

134a is not a blend refrigerant and can be charged in the vapor form. It is used in many blends but it itself is not a blend.

Art B