Convert freon/change cap tube

I have built a refrig system using parts that I almost have completely installed in my WE-6. The compressor, accum, cap tube and filter came from an old (but not too old) R22 freezer.

I think I understand that the cap tube needs to be sized based on the freon being used and the type of cooling needed (freeze vs fridge, etc).

In the event that either 1) I can't find anyone to recharge my system with R22 or 2) I do get a R22 charge and the system with the cap tube from the freezer works too well and freezes my beer, I wonder if anyone can offer some insight on a few things that I am unclear on.

How would I ask my suppy house for a cap tube to use with R134a for cooling to 38 degrees?

How do I clean out my old system so I can use R134a.

What oil is used with R134a?

[Jim]

I'm not a refrigeration expert, but I think mixing and matching components from different systems can be disasterious! Each of the seperate systems probably utilizes different oils which in most cases are NOT compatable with each other! Even if the system is vaccumed down, there will always be residue oils in the system that could clog when mixed with other oils.

You may need to seek professional advice on what you can and cannot do with the various components you have assembled...

[globalcompressors]

The problem with using used parts from different machines is making sure that everything is compatible. The first question I have is, are you sure about you refrigeration system being R22? Coming from a "freezer" that's kind of hard to believe. Low temperature machines are generally R12, R134a, and R404a (commercial) systems. R 22 was used in some "commercial" units and generally were "semi hermetic" compressors. The other problem is, like Jim said, oil residue, system contamination issues, and cap tube length.  If you are looking to "build" a unit, try and find a complete system from a modern vending machine or glass front display box. These  will generally be a 1/3 hp, medium temperature unit that should work well for what you are doing. Good Luck!

Eric

Jim/Eric - Thanks for the advice.

Eric - We have talked about replacement systems and I will be calling if I cannot get my current system to work properly, but I have to give it a try.

I should clarify that I am not mixing parts - they are all from one system. I simply replaced the copper coils and reassembled everything. By fabricating the coils I was able to change the dimensions (but kept the overall length about the same) such that they fit the dimensions of the WE-6 cooler.

It sounds like I made a bad assumption about it being R-22. I suspect it was R-12 (Whirlpool chest freezer about 8 years old). I'm now planning to use Hotshot or some other R-4XX type replacement. Any suggestions?

Also regarding my original question about cap tubes and temperatures, if this bad boy works too well (hey, it could happen:), how can I throttle it back. New cap tube? Thermostat?

Last Q - Any rough estimates on how much freon a small freezer would require?

Thanks again

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[globalcompressors]

We will still have a problem with the cap tube. The cap tube is a metering device designed for "low" temperature. You will need a different cap tube for medium temp, cap tube length, compressor size, and freon used. I can get with my suppliers and find out some of the info you need. The most important things you need to remember is the compressor, tap tube, and evaporator coil must be matched or you, a)won't reach temperture, b)coil freeze up, or c)simply won't work. A compressor comes in different sizes, like an engine block, different bores and strokes. A compressor that is a 1/4 hp low temp might be a 1/2 to 3/4 hp med. temp. Medium temperature compressors come in 1/10, 1/8, 1/6, 1/5, 1/4, 1/4plus, 1/3, 1/3plus, and so on. The other problem is the different freons. Each one will change the BTU rating as well. Do you have a tag on the compressor with it's model number?
If so, I can do some investigating and at least come close. Let me know.

Eric

Eric,

I do have the compressor tag. I'll have to look at it this weekend.

On a similar note, I'd like to understand why it wouldn't be easier to put in a thermostat for 38 degs, rather than change the cap tube. Any thoughts on that?

Also, any rough estimates on how much freon a system from a small freezer would require (I know its less than 5 lbs, but not sure how much)?

Lastly, any advice on HotShot or Autofrost X4?

[globalcompressors]

I really don't have any advice pertaining to the use of an aftermarket R12 replacement. In the vending industry, we have gone over to R134a. I don't have any idea about the others, sorry. If you wanted to use 134a, the pressure on your
low side guage, in a factory low temperature unit, will run -3 to -5 psi in a hot box. That should be close enough for cooling to take place. Again, just guessing, the amount of freon will probably be in the 4 to 6 oz. range. It depends on the size of the coils, the physical size of the compressor and whether or not there is an accumulator. If you changed anything from the original design, I really won't have any useful info though. Everything I told you is based on factory and my experience. As far as just a simple thermostat change, hey, try it! It might work. The only "custom" units I have built, have been for antique soda machines. Of course using the proper parts, coils, etc. for what ever size I'm working with. Good luck!

Eric