Rookie leak question

I have a Choice-Vend CVC-168 circa early 1970's...

R-12.   I have used Johnsen's Freeze-12 in the past (2+ years ago to boost it.  It runs fine, except when it's turned off.  Anytime it's allowed to be unplugged for a day or more, it no longer cools effectively when turned back on.  I have to add a little Freeze-12 everytime.   Sounds like a leak; but why wouldn't it leak while it was running, too?  

I don't know squat about refrigeration units, other than adding the Freeze-12 every few years.

I know I'm living on borrowed time with this unit and will eventually have to get it replaced, but I'd like to know what causes this and why it works as long as it's running?

Thanks - Mark

[davethebirdman]

Nice Seeburg....

Quote (davethebirdman @ July 09 2006,2:37)

Nice Seeburg....

Thanks Dave.  I finished it last year.   Man, had I known what the re-chroming was gonna cost, I would have bagged it!  But, I really like it.  I have 1 wall box hooked up to it.  It seems to select one record off of the one it's supposed to (just the wall box selector - the main one works fine).

Let's see yours!

[davethebirdman]

Re-Chroming ain't cheap but well worth it in the long run.
I had a similar problem with one of my wallboxes I just moved the selection strips on one. Nobody ever knew the problem exisited. It get complicated when you want to change a record though.

Good luck with you techie question someone here will answer it for you shortly I'm sure. I currently have two compressors sitting in my garage. Neither of them have been powered up for at least 20 yrs. Keeping my fingers crossed that when I get round to it they'll fire up okay. Otherwise its going to be expensive.

Dave

[johnieG]

From what you've described, it sounds like a leak on the low (suction) side of the system, I'm assuming here, not being able to see the machine & set up my gauges on it, but here goes, when the system is off, the line pressure on the low & high side starts to equalize, from a low pressure of about 18psi
to around 60-70psi when every thing balances off, it could be a pinhole leak in your evaporator, when exposed to the higher line pressure leaks, but when you "top it off" & start it up, well know the lowside will below the pressure point that supports the leak, I'm not familiar with freeze-12's pressures in a system. you'd really need to put a set of gauges on the system to observe whats happening.

[globalcompressors]

Johnie,

You explained it perfectly...even more so if the machine is out in the garage
or on a back porch. Higher temperatures...higher pressures.

Eric