Central AC copper lines when replacing AC system

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  #1  
Old 09-30-18, 06:24 PM
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Central AC copper lines when replacing AC system

I seem to have a freon leak someplace in my AC system. I had freon refilled and it worked well and kept my home cool for about 2 months and after that it kept warmer and warmer. AC runs, but it's just not keeping the inside of home cool enough. I kind of suspect that the leak is inside the home on the evaporator coil because if it did freon would have leaked inside my basement and spread to the rest of the home, and I would have gotten sick from inhale freon I believe (please correct me if I'm wrong). I suspect the leak is most likely on the outside unit. I met with some techs and sale reps from HVAC contractor businesses, and they all said like "since the AC system is 13 years old, we don't recommend investing in fixing the leak. If you decide to fix the leak, it will cost any where from about $800 to $1,800". I'm leaning toward getting AC system replaced, but my dilemma is all these AC contractors want me to sign the contract, and on the day of the AC replacement, if a leak is found on the copper lines following nitrogen test, then another quote will be provided. The majority of my copper lines are buried in the drywall ceiling which would make replacing the copper lines more difficult and expensive. On my drywall ceiling where the copper lines run, I don't see any stains which I suspect would be present if the leak is on the copper line. What would be the best thing to do? Finding a leak alone seems to cost anywhere from $400 to $1,000 the cost of which I would like to avoid if I can be reasonably sure if leak is not on cooper lines. Your opinions?
 

Last edited by BeingCareful88; 09-30-18 at 06:27 PM. Reason: typo
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  #2  
Old 09-30-18, 08:08 PM
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One of the ac pros should be along, but I can address a couple of items.

There's really no way of knowing where the leak is without a leak test of some kind. I doubt that even a large leak would cause any noticeable medical issues. Your house is not a sealed box and the air inside gets exchanged on a regular basis, i.e. every time you open a door you get a little bit of fresh air.

Down here AFAIK, the line sets are routinely replaced during an installation (my own AC is about the age of yours; it's line set was replaced when it was installed). So, just to elaborate a bit, you have no attic or crawl space above the ceiling to access the lines? But the air handler is up there? Sounds a bit odd, so you may want to add some amplifying info on that for the pros. If the lines are not accessible, it would make it pretty hard to leak check them other than capping both ends and pressurizing (as opposed to pressurizing the entire system and seeing if there is a leak SOMEWHERE in the system).
 
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Old 09-30-18, 08:15 PM
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I would have gotten sick from inhale freon I believe (please correct me if I'm wrong).
You're wrong. The little bit it leaks is quickly dissipated into the air.

The most likeliest place for a leak is inside at the evaporator coil as this where all the corrosion occurs.

If you don't plan on replacing the lines completely..... then a test must be done. Most companies will not install using old questionable piping. Now the lines are run up the side of the house and into the attic. The old ones would be abandoned.
 
  #4  
Old 10-01-18, 07:33 AM
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Since your profile says Maryland, I will assume that the A/C lines and evaporator coil is in the basement and basement ceiling as you alluded to. That being the case, if you replace the whole unit, you may have to replace these lines depending on compatibility of the refrigerants used. To replace the lines you may want to cut the dry wall or run the lines exposed.(That is the problem with a drywall or plaster ceiling in a basement or utility room. I would try this first. I would mix up a soap solution and apply it to the A/C line connections And look for bubbles to form. (you can also buy some at the Lowes or Home Depot, or any large hardware store). Then look all over the coils that you can see for any oil residue. If you find oil residue that may indicate the area of the leak. A contractor can also install a colored leak detector in the system which may help locate the leak. I would try the least costly methods before I opt for replacing the whole unit. My 2 cents.
 
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Old 10-01-18, 07:35 AM
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Pete, I'm curious, what are your thoughts on the locate/fix possible leak on a 13 year old system vice going the replace route? I hear this question get kicked around a lot (we use a bit of AC in Florida). By coincidence, as I mentioned, my system is the same age. Working fine after we located and fixed a leak last year. Mine was a line leak just downstream of the compressor though, so pretty easy find/fix.
 
  #6  
Old 10-01-18, 09:53 AM
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I would try to find the leak myself. It takes a good sniffer tool and a company that actually wants to repair a leak versus selling new equipment.
 
  #7  
Old 10-01-18, 11:13 AM
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Thanks for all your responses. Air blower is in the basement where the gas furnace is, and the copper lines run from evap coil in the basement casing through the basement ceiling where there's no crawl space and no attic thru the drywall, and comes outside on the exterior siding. I think to replace the copper pipe, it needs to be pulled out from outside after cutting it off the inside basement evap coil casing.

In this case, there is no way to get to the most of the copper coil as far as I can see except where it goes into the drywall ceiling and where it comes out of the exterior siding on the outside of home. Can I still buy sniffer or use soapy water to try to find the leak.

Another question is when I turn on the AC, I can see the outside fans runs, but I do not know if the outside condenser is running which is kind of similar situation as another poster at https://www.doityourself.com/forum/a...can-check.html

I opened the side panel, and it looks like I have a dual capacitor that runs both the fan and condenser. See the pics at below links please. It looks like I have a motor run capacitor SA9117.
https://www.dropbox.com/s/a82zmxffx9...23634.jpg?dl=0
https://www.dropbox.com/s/eh06b5ahrb...23701.jpg?dl=0
https://www.dropbox.com/s/ddcyklgqtv...23756.jpg?dl=0
 
  #8  
Old 10-01-18, 02:14 PM
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Like said have them do a pressure test on the lines before. If good then blow them out with r-11 flush and hook to the new system. If its a line set there should not be any joints except at the units.
Have them give you an add to replace up front.
 
  #9  
Old 10-01-18, 05:28 PM
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Sure you can use a sniffer if you want to buy a decent one that works. Soap and water is not effective as all the lines are not under high pressure.
 
  #10  
Old 10-01-18, 06:18 PM
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I used this to verify an "ant dust" leak on 50 year old air handler expansion valve fitting. There was white dust on fitting and the detector developed fine bubbles. Static pressure on suction line was around 100 PSI when system was off.

https://www.supplyhouse.com/Hercules...-8-oz-w-dauber

https://www.supplyhouse.com/Hercules...6-oz-w-sprayer

Here is an interesting item on AC leaks:
https://www.achrnews.com/articles/10...rrosion-issues
 

Last edited by doughess; 10-01-18 at 08:31 PM.
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