Will My AC unit keep running

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  #1  
Old 10-13-07, 06:08 PM
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Thumbs down Will My AC unit keep running

Our 9 yr old Lenox 3 ton AC/Heat-pump went out a few weeks ago. Had and AC Repairman come to fix it. He Hooked up his gauge to the unit and said it was empty. (less than 20 lbs pressure). Charged it with 6 lbs of R22. Said it worked great and charged me $200 He was there 15 to 20 Minutes. (R22 @ $16/lb)

Call him back the next day because it quit again This time he used his leak detector and found a leak in the evaporator in one of the small capillary line. Said it had rubbed on something. He silver soldered it up and charge the unit up without checking for anymore leaks other than leaving 70 lbs pressure of R22 on the system to see if it held for 5 minutes. He then charged it up again. Did not pull a vacuum.

This time the bill was $450.00. Well it lasted 6hrs then couldn't cool down the house. I called him and said it quit again. He said it must be another leak.

Now it was the whole evaporator that was full of leaks and needed to be replaced with a new one. This time the bill would be close to $1000 to replace the evaporator, pull a vacuum, install a dryer, and recharge with R22. But I was not home when he fixed it and now I see that he didn't install a filter/dryer. It does seem to be working now.

My Question is that the best I can remember is that if a system is opened up to change a major component that it needs a filter/dryer and a vacuum pulled to remove contaminants. If this is not done, that the freon will become acidified and ruin the compressor windings. Will it keep running as is or damage the compressor?
 
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  #2  
Old 10-13-07, 06:52 PM
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most people would not have known the difference, I guess you have been reading the threads a bit. You have a increased chance of having future problems if a your system is not serviced correctly. How much of a chance would really be hard to calculate. That guy has probably done the same thing MANY times before. If anyone challenges him his reply will be "well I have had not had any trouble out of doing it that way" and you know what HE has not had any trouble out of it at all, its the poor customers.
 
  #3  
Old 10-13-07, 09:32 PM
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So it looks like I may need call number four. How long will it probably run without a filter/dryer? Days, Weeks, Months, or Years????????
 
  #4  
Old 10-14-07, 04:08 AM
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That's a tough question and the answer could be any of the above. I see systems that are 20+ years old with no filter/drier. I not saying it's OK and it's something I certainly wouldn't do. But, I make the customer aware of it.

In theory, if the system is clean, a nitrogen purge was done and a good vacuum pulled you should be fine. In such cases, the filter/drier is low cost insurance.

My concern is your mention of not pulling a vacuum for the first repair. This makes me wonder how the later repairs were done.

Sorry I couldn't give you a more definite answer.
 
  #5  
Old 10-14-07, 07:57 AM
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Well! I don't know what to do. I did AC work back in the sixties for about six months as part of my apprenticeship at a large corporation. There were all larger industrial units but I remember anytime the system was opened up, the guys would always pull a vacuum (some time over night) and install a filter/dryer.

I may call around Monday and see what someone would charge me to pump the system down and put in a dryer. I just cant deal with this guy anymore. I should of known the first call when he charged an empty system that had worked perfect the day before without checking fo leaks. And then the 2nd call when the repair of a leak caused by rubbing lines caused the whole evaporator to leak. His work isn't worth a dime but he sure talks a good line and is about to break me.
 
  #6  
Old 10-14-07, 09:57 AM
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It is possible he replaced the filter/drier in the condensing unit. Lennox usually has one there. I would at least look in there before spending more $$
 
  #7  
Old 10-14-07, 10:37 AM
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I went out and checked the condenser. My mistake, it is a Bryant 661CJ036-A not a Lenox. Anyway there are two lines between the Compressor and the heat-pump 4 way valve. The 1/2inch one has a 3" long by 2 1/2" round something in it. The 3/4 inch line has a 8" tall by 5" round (kind of big) something in it. Kind of both look like they could be dryers, or could be some kind of accumulators. But they are both original equipment not new.

So if they are filter/dryers, would they still be good??? It may be that he knows they will protect the unit from contamination. ???? Please advise, I probably wouldn't believe it from him.

Thanks in Advance
 
  #8  
Old 10-14-07, 02:59 PM
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What you describe is an accumulator plus a possible filter/drier. Filter/driers should not be re-used.

It appears you are really stressing about this. Your suggestion of getting someone else to finish up may offer peace of mind.

For best protection, have the new tech recover old freon, remove old filter/drier (if there is one), install new filter/drier, do nitrogen purge, pull a deep vacuum and recharge with new freon. If you want to go all out (may be overkill), install two filter/driers (one liquid line and one suction line) and a dry eye (this is a sight glass which indicates moisture in the system).

Running the vacuum pump all night is not necessary on residential equipment (a micron gauge will let you know), but is required on large commercial equipment.

Good luck. Let us know what you decide and the outcome.
 
  #9  
Old 10-14-07, 03:54 PM
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Yes I am stressed out about this. It may be no big deal to some to spend hundreds each week, but to me it is. I have spent $1600 so far on three service calls and need this problem to go away. I am afraid I still need to spend more because I had a repairman that always wants to setup for the next call. I will take your advice and get someone else.

Does the freon (R22) become acidified when the unit is not running. In other words would it help to leave it off in the nice fall weather for a few weeks till I get someone else and save up some money for the next bill.

thanks
 
  #10  
Old 10-14-07, 05:07 PM
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If there is in fact moisture in the system, then leaving it off would help. To the best of my knowledge, the formation of acid only occurs when the system is in operation. It's the combination of temperature and compression that causes the chemical reaction. I have never heard of acids forming outside of an operating system, such as in a tank.

If anyone else has addition information, please jump in.
 
  #11  
Old 10-15-07, 07:08 PM
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I call the AC man today and asked him why he didn't put in a filter/dryer like I asked. He said he didn't know I wanted one. Said he left the nitrogen on and purging the whole time he was soldering in the evaporator. Then he pulled a two hour vacuum on it. Said that he was confident that it would last and repair it if it quite again. I guess I will leave it at that.
 
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