Question about A/C freezing (again)

I know this subject has been raised over and over, but of course I paid no attention until I actually had the problem myself. Picture a central air system that's been no trouble (unless you count the dead snake I had to fish out of the compressor fan once) until, naturally, the hottest days we've had in several years (and I do understand about "design point"). Cool-ish air from the vents and not much of it, so of course I realized I'd let the filter go too long. It was dirty, my A-coils were blocked and encased in solid ice so I thawed it all out, replaced the filter, cleaned the A-coils, opened and cleaned the coils on the outside part of the unit, and everything worked fine for about 24 hours. Then the same problems -- not very cold air (8 deg F temperature differential) and iced-up A-coils. I found some leaky seams on the back side of the ductwork and figured too much air was bypassing the coils, which I thought might have caused the new freeze-up (I got a D in Thermodynamics in college, so I might be totally wrong about that). Fixed the air leaks, reopened and re-cleaned the outdoor parts just to be sure, and waited several hours to see if things would improve. I get a lot more airflow from the vents but it's still only 8 deg F differential, so I'm thinking low freon -- which finally leads to my question: Can low refrigerant and coil freezing go together, once the coils have been thoroughly cleaned and air leaks sealed? The big copper line into the unit was ice-cold when all this started but is just barely cool today. I'm trying to nurse this thing through one last summer -- my daughter's finally out of college and I can use the money I usually spend on her tuition to replace the unit in a few months, if repairs aren't feasible. - Steve Richardson St Louis MO
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Steve Richardson wrote:

Low evaporator heat load and/or low charge.
hvacrmedic
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The suggestions about low freon charge were right on the money, once I got it through my head that too LITTLE refrigerant could produce a huge solid block of clear ice in my coils. The air conditioner guy was here today, never even had to go inside to look at the coils. His gauge on the line showed 50 where it should have been 80, so a quick top-up of refrigerant put everything back in perfect shape. A good thing too -- tomorrow every window in the house is being replaced and I'm going to the poorhouse, so there wasn't anything left in the kitty for major A/C repairs. Thanks everyone! - Steve Richardson St Louis MO
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uh-huh.

If your AC guy didn't check the WB RA temp, he bent you over real well.
You got a gas-n-go. You didn't your AC serviced, you got serviced.
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How true.
If he didn't find and fix a leak, you are now "renting" refrigerant. In other words, you'll be calling SOMEONE back out later (probably on the next hottest day of the year). Sure, it will get you A/C for a while, but it won't last. There is a leak somewhere and they don't get smaller.
Save "topping up" for your gas tank or your beer.......
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Well gee, guys, that's a little harsh, after I thanked you for telling me about low refrigerant and coil freeze-ups in the first place! It took 6 years for the last top-up to bleed down, and I think I can stand that kind of "cheating". The unit is nearly 20 years old, my goal was to get it through this season, and I don't mind "renting refrigerant" at these prices -- $111 is something I can afford if it holds together until cool weather. Maybe you folks have the luxury of cash reserves to tap into on short notice but I sure don't! In my particular (post-divorce) corner of the Real World we do the best we can with what limited resources we can scrape together at the moment, and in this case it meant applying a band-aid because literally all my ready cash had been spent on new windows (due to be installed today -- but no sign of them yet). But thanks for your concerns and suggestions. When (notice I'm accepting that your point that it's not "if") the old system fails again, you've at least given me insight into what comes next, and I'm always grateful for technical expertise. - Steve Richardson St Louis MO
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Here is another homeowner that got screwed big time. PRESSURE ON THE FRIGGIN MANIFOLDS MEANS NOTHING!!!
It is ONE TOOL out of many that your AC guy should have used. Did he get the return air temp? No. Did he get a dew point reading? no..did he get a return air temp reading and supply register reading? No... Your unit isnt in perfect shape...its leaking...or you have a clogged coil...and you wont know, since you got bent over and didnt get kissed. Did he check for a leak? Did he check to see if you have a low airflow condition? Did he check to see if you had a blower that was shutting down? If you have a Goodman heat pump, did he check the blower sequencer to see if its the piece of shit that fails like clockwork?
Did you pay for refrigerant, and if so, did he use a SCALE to weigh in the charge? If you paid more than $40 for this hacks BS work, you got ripped off...personally, if all he did was gas and go, I would not have paid him a cent and have advocated this for years in here.
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Steve Richardson writes:

It's paradoxical, but true:
http://groups-beta.google.com/group/alt.home.repair/msg/0420eda678cc180f
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Suddenly it all makes sense. Thanks!

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