Old Traulson troubles

[jjust61]

I just inherited an old RHT 2 32 LUT 2 door reach in. I'm the seven hundred and fifty third tech that has worked on this unit. First thing I noticed was a newer condensing unit that looked as big as a walk in. Replaced a leaky rotolock valve at compressor and liquid line filter. Unit was originally R-12 and someone labeled it at some point with R 416a so that's what I used. As I was working on this monster I started to look at some model numbers. RHT 2 32 LUT is a 4700 BTU freezer. The condensing unit is a Tecumseh AHA2466Axdxc, 6900 BTUs at -10. This condensing has a receiver and evaporator has a cap tube. I've never delt with a unit that is as mismatched as this one. Replacing the condensing unit at this point is not an option so I need some out of the box help. When I ran the unit after charging I had about 75 psi on hi side and 10 to 15 in hg on low side. Liquid line room temp. Box was pulling down but I did not want to see low side in such a deep vacuum so I installed a condenser fan cycling switch and I set up to cycle fan on at almost 200 psi and off at about 150psi. That keeps my suction pres at about 0 psi to about 4 psi. The freezer dulled down to about 10 deg and suction line starts freezing at about 13 or 14 deg. Liquid line temp is now about 105 to 109 f. Unit seems ok except for a little ice on suction line. Any thoughts as to what I did and what I might do to get it down a few more deg, or is this the best that I might expect. Thanks.

[Phase Loss]

ditch the receiver and keep the cap tube.

or

keep the receiver and ditch the cap tube and install a TXV.

[jjust61]

ditch the receiver and keep the cap tube.

or

keep the receiver and ditch the cap tube and install a TXV.

Yeah, I should have removed receiver when I had system open. I will if I ever open it again. Unit is pulling down to single digets.

[J_Bridge]

Go TXV, it will repond better and you can know with a full sight glass you are properly charged. Plus you will get more precise adjustment from the valve. pump unit down, install txv, change drier, add sight glass and pull vacuum. Then let her rip, easier than removing the receiver tank and a quicker repair.

What other refrigerants can that condensing unit handle?

[jjust61]

Go TXV, it will repond better and you can know with a full sight glass you are properly charged. Plus you will get more precise adjustment from the valve. pump unit down, install txv, change drier, add sight glass and pull vacuum. Then let her rip, easier than removing the receiver tank and a quicker repair.




What other refrigerants can that condensing unit handle?

With this system as mismatched as this one is, would you use a txv that is sized closer to the evaporator capacity or somewhere in between condensing unit capacity and evap capacity? The condensing unit is almost 50% larger than evaporator.

[Phase Loss]

Yank out the R-416A, it's intended use is AC.

Put in R-401B and install a SBQE-AA-FZP

[jklondike]

R416a will go into a vacuum at -9 deg and is used for a/c and medium temp applications,high temp glide aswell.First thing to do is pull out existing freon and change out,also agree with r-401B. To be safe,pull out captube and install txv,rated inbetween cond. and evap capicty for best bet.

[evilsanta]

Push it off a cliff.