Air Conditioning - AC weak; evap frozen; top evap warm; Lo press 45, Hi press 200

Realized AC not working too well 1 month ago - found evap covered with ice and drain tube partially clogged. Air filter was clogged but it's been clogged like that before without problem. ( I change it monthly.) I ran fan to thaw ice (after trying hair dryer for a few minutes - foolish, eh?)

AC has been getting weaker since. Checked pressures tonight (82F) - they were 45 and 200.

The top half of the evap is not getting cold while the bottom half is cold (end tubing has frost).

System is original - about 22 years old. I'm guessing it a 60% eff unit. Holds 4.5 lbs R22 per the label. Don't know the size as I couldn't find the rating anywhere. It's a BDP (Carrier, I think?) compressor Model 565BJ030.

I realize it's old and needs to be replaced - the heat exchanger is also in bad shape. But since money is tight right now, here are my thoughts:

1) charging it just to get us through the summer St. Louis heat.
2) in October, replace it with a high efficiency unit.

I fix cars 'on the side' - engine swap/rebuilds, etc., including AC work. I have a pump and the gauge set (used to get the numbers above). So, I can do the charge myself, assuming I can get some R22 cheap enough.

I'm also considering doing the replacement myself. I can solder copper and I've worked with 220 (replaced our gas stove with 220 unit, per code). I'm an electrical engineer by education, and I've helped build a few homes with family.

So, I'm looking for advice:
- is a charge likely to hold, considering the evap freeze issue?
- is a diy furnace/AC replacement really impossible for someone with my background?

Thanks.

Sorry, even if you have prior experience with working on the pressure parts of refrigeration systems (I also do) and unless you hold current certification from the Environmental Protection Agency you are NOT allowed to work with refrigerants and cannot even purchase them.

I know but I'm not concerned by that. 609 certification can be had via EPA's website http://www.epatest.com/609 and they even offer an open book test, which I think is kind of ridiculous.

By the time I do this I'll be 609 certified to purchase less than 20 lbs. Having said that, I fully acknowledge that passing a cert test is not the same as having experience. So, I was wondering what some of the gotchas might be for this task.

I'm still curious as to why 1/2 of the evap is cold, the other warm.

Thanks,

they want you to be EPA certified because freon is bad if it escapes out into the atmosphere thats why they want to get rid of R-22. as far as 1/2 warm 1/2 cold half the coil could be blocked or damaged. you could try cleaning it.

I think you may need a 608 certification instead of the 609 (609 is automotive MVAC I think?), but check and make sure. You might consider taking a Refrigeration Repair course at your local community college, the knowledge gained and the 608 cert, that normally comes with the course, would most certainly set you on the correct path for a successful repair or replacement as required. A friend of mine teaches part time at a local college, he has been known to hold field trips where the entire class meets at someones house and does some hands on installation and or repair work

In spite of your attempt to skirt the intent of being properly certified, "charging it just to get us through the summer St. Louis heat" is the reason CFC regulations were written in the first place.

We do not support DIY sealed system repair on these forums but there may be other websites that do.