Charging a Westinghouse compressor questions

[tkaz]

I have a Westinghouse standard that needs a freon charge, so here's a few questions.  The unit has a couple charge valves on it, is it worth it to just go grab some R134 from an auto store and charging it up to see if it works better?  Is this going to cause any problems?  I assume I should swap out the valve stems if I do give it try.  The machine sat for over 20 years, so I am not sure it has any leaks, I figured that I'd give it a good check once it is charged.

[johnieG]

Do NOT add R 134a to an R12 system, it will react with the old refrigerant & oil , and probably seize up your compressor, besides the point that it's " Illegal " to do so ( mix refrigerants ) & without a gauge  set to determine how much ( or how little) charge is in the system, you could fudge it up pretty good. And if you accidentally try to tap into the high pressure side of the system, you could rupture the can ( this means it will explode)

Assuming the system is discharged, there's a leak somewhere that will need fixing, (probably one of the multiple clamp-on line taps you've found ) You could use old-stock R12 if you have it or an R12 substitute, like freeze-12, (Hot-shot /R414a is a good substitute, but you'll need to be licensed to purchase it. ) I don't like frost12/ enviro-12 as it's basically butane & flammable.  

[tkaz]

Thanks, that was the answer I was looking for, I figured it wasn't as easy as I thought.  With not knowing the history of the compressor, I'm going to assume that I can figure out the type of refrigerant by checking the thread on the ports?  I did some research and found that the R134a is a 1/2 - 16 thread, so I'll have to check that when I get a chance tomorrow.

What's a decent price that I should look for to get this leak tested and charged?  Should I just call up the guys that do my house A/C to get it done?

[johnieG]

"home" AC techs may only use R22 or nowadays it will be the newer R410 , & but they may take a look at it for you.

[loman4ec]

My guy charges $150 to diagnose' fix leaks, replace filter/dryer, vacuum and recharge. I figure that s a great price.

[Yarochrehc]

Not a bad price Josh, and as JohnieG says it's not as easy as it sounds to do a proper job.