Rookie refrigeration diagnosing

I have a Choice-Vend CVC-168 (yes, the AMC Pacer of soda machines, apparently).

It doesn't cool.  The evaporator is icing up in the top corner, where the small  line comes in.  It's reading about 18F.  However, the evaporator isn't cold, except for that spot.

Does this sound like a clog, not enough refrigerant, or something else?  

I called a few AC places, and they want $400 just to recharge it (R-12 '> )   I am considering getting a rebuilt R134 unit from Global if there isn't a cheaper fix.  

Any suggestions appreciated!

Ace

I'd go with global.  Eric at global is a great guy and does excellent work.  So far he has reconditioned the refrigeration decks from two of my machines and I have no complaints.

[johnieG]

Is your evaporator fan blowing air into/around the cabinet?
if not, your coils will get cold but not soda...just a thought,

Quote (johnieG @ April 15 2004,11:48)

Is your evaporator fan blowing air into/around the cabinet? if not, your coils will get cold but not soda...just a thought,

The fans are working.  I took the can rack out to get a good look at the evaporator.  The small copper line (the non-gas line) gets cold and about the first 3 inches of the evaporator gets cold, near where the line goes into it.

[globalcompressors]

Ace,

I sent you an E-mail as well. When we have a unit not cooling correctly, we need to look at all the signs. As Jonnie mentioned, the 1st thing, is to make sure the fans are working. Next, make sure the compressor is running. Look for a frost line, as you have, on the smaller cap tube. If the frost is running back down, away from the evaporator, usually a couple of inches, the unit is undercharged. The only way a unit can be "undercharged" is if there is a leak. Remember, this is supposed to be a "sealed" system. If the machines sits for a long period of time, moisture will build up in the cooling compartment causing the copper tubing to corrode. A little FYI, when storing a machine, leave the door cracked open to prevent moisture and mold build up. If you read Jonnie's other discussion about charging, he mentioned Hot Shot, a replacement for R12. This can be used to "bump" the charge and get the unit running properly. Sooner or later, the leak will get worse and will need to be addressed. Also, make sure the unit coils, upper and lower, are completely clean. This is probably the MOST important thing an owner can do for his machine. Good luck with it and if you have any questions, call me toll free at 1 877 856 4996.  '>

Eric

Eric - thanks for the insight.   I'm gonna give the cheap-fix a try first.  If that doesn't cut it, I'll be ordering a refurbished unit from you.  Thanks again and I'll post my results here in a few weeks when I get all the parts.

Ace

[johnieG]

I've had some nice results fixing pesky pin hole type leaks on machines that some of my customers didn't wish to put a lot of money into, It's a stop leak by "Quest" part no. 326 for R12 & R22, it actually forms an epoxy "scab" at the site of the pin hole, it comes in a can with automotive style threaded nipple on top & it's supplied with its own hose ( looks identicle to the Quest part no. 325 stop leak for R134A/automotive applications, and NO you can't use the R134A product in your R12 system as it's using R134A/Pag oil as a propellant & won't mix)the can is vacuum packed (which mean you have to hook it up to your system to get R12 into the can to act as a propellant,( instructions are include so don't worry) I order mine thru CarQuest Part stores about $25 retail. this is just a thought, it also contains a leak detector to pinpoint the hole
it won't fix major holes, but seems fine for those little slow leaks, I'm always trying something out in the "Barn" to keep these machines humming along! hope this helps...JohnieG

heres the link to EF product (Quest)http://www.efproducts.com/
and the product link is as follows
http://www.efproducts.com/productview.php?id=326

johnieG - thanks for the tip!   Did you have a valve already on your system to connect the hose to, or did you put in a saddle valve to tap into it?  It looks like my unit may have had a small leak, as evidenced by very light green stuff on the side of the evaporator.  I really appreciate the post, thanks!

Ace

[johnieG]

In your case you'd be installing a saddle valve, be sure to clean the area of the suction line you'll be clamping onto,
use a scotch brite pad or fine steel wool to get the copper line nice & shiny, I prefer the Robinair valve part no.40330 as it has a built-in valve core, the section of line should be on the suction (low) side of the system, that is the part of the tubing [/U]after the small cap (capillary) line up in the cold part (evaporator)of the system, that goes from the evaporator back to the compressor, if you do go with the stop leak, take it over to your guy & have him pre-charge it with R12, the valve that comes with the stop leak kit will keep it in the can until you get home, it will save you a step, & you wont have to monkey around trying to get enough R12 into the can (to  be used as propellant). as a guide, I can still get R12 around here for around $40-60 a pound/12oz. can
so don't let them "hose" you. thats why I use R414B  it's less than $12/pound. let us know how it goes!    '>

JohnieG - I'm having trouble locating the Robinair 40330 valve.  Do you know of an online source?  Thanks - Ace