Mini Fridge repair

[Brewer87]

I have a little black GE fridge that I bought in college. I am a home brewer and decided to make the fridge my wort chiller. I have a temp controller to keep the temp at a nice cool 65, and I hooked it all up, works great. I then (very stupidly) decided to mount the thing on the side of the fridge. I drilled a hole in one of the R 134a lines. Like I said, really stupid mistake. I was able to seal the hole using a small piece of metal and some epoxy, but now (obviously) the fridge has no r-134a. It also has no fittings, just three lines coming out of the compressor, the send and return, and what I'm assuming to be the fill tube from the factory, which has been crimped and brazened shut.

I'm really stubborn, and have an MS in engineering (though I have occasional lapses in common sense). I don't want to buy a new fridge, and I don't want to take it to a pro. I really just want to get a little can of r-134a and get it into the fridge somehow. I'm thinking I can cut off the brazened/crimped part of the fill tube, install a valve and compression fitting. What could I do after that? Could I jimmy some kind of adapter to go from 1/4" line to the can? Or do they sell something at home depot or somewhere online that could go between the can and the 1/4" line? What kind of pressures are involved?

I'm also guessing I'll need to have a vacuum to pull the r-134a into the system and replace the air that is currently there. Could I turn on the compressor while I do it and create the vacuum that way?

I know, I could just buy a fridge on craigslist and call it good, but I really want to repair this thing, I think it would be fun and I like learning how things work. Also, I want to redeem my stupid actions with some decent fix it skills. Bear in mind that my requirements for this fridge are pretty minimal, I only need it to get the stuff inside down to about 65, so a partial solution is also welcome!

[ar_hvac_man]

I make beer too and have thought of making a little wort chiller. Right now Im still using a wash bin and ice water.

Without going in to a lot of detail ill tell you that no, you cannot use the on board compressor to pull a decent vacuum. You dont have the tools to do what needs to be done to make it work again. A pro repair would run you close to or more than a new mini fridge.

[vzenuh]

agree. The only time it is worth while to fix it is when you already have the equipment. You could consider taking it down to your local community college and have them work on it. Young students love to fix things that normally would be thrown away. I wouldn't be surprised if they did it for free.

When I went to school our teachers always asked us to bring stuff in. The only charge would be for major components such as compressors and motors.

[Tommy knocker]

Agree with vzenuh. They are basically disposable. Love the v-tech school idea. Worth a shot. Good luck.

[2sac]

You can get a new one for under $100. 'nuff said.

[jpsmith1cm]

You can get a new one for under $100. 'nuff said.

I've got the tools and the knowledge and I wouldn't mess with fixing it.

[VTP99]

O.k. it's looking like no one here is going to help ya out. Should I give him step by step instructions or are open workshops not permitted ?

[carmon]

its 101 repair instructions may be a poor idea

[danbb]

Yeah, even with all the proper tools and knowledge, most of us would have to agree with JP- Most professionals wouldn't fix it if it were their own, much less try to walk someone through it. Let's face it, an epoxy repair probably isn't going to hold up or be leak-tight, you would need a professional vacuum pump (300-500), a compression fitting on the process tube (that third tube coming out of the compressor that is capped off) would be a constant leak, you'd have to beg, borrow, or steal a whole lot of tools to do it properly. I will, however, throw you a bone- Any auto parts store should sell small cans of 134a. If you can find a way to make this system leak-proof, and get the system evacuated and then find a way to get the right amount of refrigerant out of the can and into the system, more power to you.

[brewidus]

I'm a brewer too. I use a coil of 3/8" copper as a wort chiller. I drop it in 20 minutes before the end of the boil. During the winter, the tap water is cold enough to lower the wort temp to 70. During the summer, I use a second coil submerged in an ice water bath as a pre-cooling coil to sub-cool the tap water before it gets to the main coil. When the wort gets down to about 100, I drop a submersible pump into the chilled water and pump the chilled water through the wort coil and back. This cools it down to 70 in just a few minutes. This whole process takes less then 30 minutes.

Now have you calculated how long it should take to cool your batch with your refrigerator. I make 5 gallon batches which is about 42 lbs. Assume the wort has a similar specific heat as water at 1 btu/lb. In order to cool 42 lbs of wort from 212 to 70 would require (212-70) * 42 = 5964 btu.

That would take a fridge with a 11,928 btu/hr capacity to cool the wort in 30 minutes.

[ICanHas]

On the same topic... could you add more refrigerant to a chest freezer to up the evaporator temperature for keg use?

Seeing that low charge leads to coil freeze-up when you up the charge, wouldn't it raise the SST thus raise the evaporator temperature?

If I'm wrong, how is the suction pressure (which sets evaporator temperature) set?

[Juan Madera]

These are (very) critically charged systems. Look on the tag and notice that the charge is weighed in ounces and hundredths of an ounce. I won't even think of recharging these when you can buy a new one sooooo cheaply. Las one I had was a wine cooler with a glass door. Gave it to a guy that uses it to brood reptile eggs.

[ICanHas]

Ok, but "it's cheaper" is getting to be an excuse for technical incompetency these days.