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Old 01-10-2011, 04:04 PM   #1
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Condenser/Coil Install Questions


This fall I installed a new furnace and completed much of the work for A/C side including setting and wiring the condenser, running the lineset, and setting the cased coil when I installed the furnace. At that time (early October) I started using the furnace and it continues to work fine and I am very happy with it.

Because of the tools involved and the expertise required, I hired a contractor to complete the installation of the AC. A number of items have now come to my attention regarding the final stages of the AC install that I believe may have been completed improperly. The contractor I hired was not an authorized installer for the brand I chose, but was an authorized installer for another major national brand.

Here is a list of items that I suspect where done improperly that may affect the efficiency and longevity of the system:

Strike one: When I installed the lineset, the plug on the 3/4" line came out and remained unplugged and open to the atmosphere for the approximately three weeks from the time the lineset was pulled until it was brazed.

Strike two: When the contractor brazed the lineset, he did not flow nitrogen.

Strike three: The contractor did pressure test the system with nitrogen (about 20-minutes), but he did not use any extraordinary measures to counter my mistake of leaving the system open for three weeks. He did run the vacuum pump for about 30-minutes, but did not "triple evacuate" or use other, more thorough, measures.

Strike four: The contractor appeared to use a "seat of your pants" method for determining the proper amount of refrigerant to be added to my approximately 25-foot lineset. He did not weigh the additional 410 added or did he use sub cooling. He did, however add some 410.

Once those items were completed, he did run the system for about 20-minutes and did measure the temperature drop from the return drop to the supply side plenum and found it to be "good".

So, here I sit, suspecting that the condenser and refrigerant loop portion of my new system has been installed, at least in part, incorrectly. I take full responsibility for the errors that were made (I made one of the myself directly and was less than fully educated on the others items and hired a contractor that was less rigorous than he should have been).

Questions:

1) Do I need to do anything now? It is the middle of winter and the temp this weekend was -10.

2) What if anything can be done next spring? Should the system be fully pumped down, properly evacuated and recharged using SC? There is a line drier that was installed right next to the coil.

Thanks for all of your help.


Last edited by civiltoatee; 01-10-2011 at 04:06 PM.
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Old 01-10-2011, 04:27 PM   #2
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Condenser/Coil Install Questions


I hate to say it but VERY few installers flow nitrogen thru the lines when welding. It is expensive and time consuming and most guys cannot weld with pressure in the lines or know how to throttle it down enough to weld that way. Not saying that is right but it is the way it is from what I have seen. I have not had a system ever get plugged with carbon or debris from welding except for a glob of silfoss and one system with moisture/flux turned into wax and clogged a strainer at an orifice. I would not worry about the welding job. I would however get it pumped down and a proper deep micron vacuum pulled and a new liquid line drier installed. If you want to spend some $$ to be safe a suction line drier can be installed. Then it needs to be charged properly with the superheat or subcool method. That is your biggest problem because if it is overcharged then liquid refrig can get back to the compressor and wash out the oil and damage it.

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Old 01-11-2011, 01:17 PM   #3
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Thanks, Yuri,

Regarding flowing nitrogen while brazing, with my limited experience, I would agree with you. A few days after he had brazed the joints and when I had read it is best to flow nitrogen, I went back to look at the joints. There was still black sooty material on the joints next to the coil and on each side of the liquid line drier. I am assuming that this sooty layer is similar to the residual material that forms on the inside of the joint when not flowing nitrogen.

I wiped my finger over the joint, transferring some soot to my finger. I rubbed my finger and thumb together and I could not perceive any grain, texture, or cohesion to the ashy soot, even with my "subtle, office-bred fingertips". It would be nearly impossible for me to believe that this material, when mixed with oil, could become an impediment to a mechanical device based on its grain size or cohesion. I can see how manufacturers would think it is better if it is not in the refrigerant stream, but why exactly it is detrimental, is not clear.

Regarding your other recommendation to "repair" my system, I have a couple of related follow up questions:

1) Is the refrigerant currently contaminated beyond repair? That is, are you recommending the refrigerant be removed and discarded before re-evacuating the system and installing all new refrigerant?

2) Is the real issue the charge or the contamination? Would it be acceptable to have a technician,using subcooling, adjust the refrigerant, but continue to use the existing r410?

3) How much moisture could have been in the lines? What portion was likely removed by the 30-minute evacuation? Is it possible that the existing line drier would remove the moisture in the line?

4) Does any of this need to be done before next spring? Is the contaminated r410 currently damaging the compressor?

Thanks again. I really appreciate your comments.
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Old 01-11-2011, 02:52 PM   #4
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Condenser/Coil Install Questions


If you think that it was not done properly, call another HVAC contractor that is reputable to come look over the system before firing it up for Spring. Just keep the Electric for the outside unit tagged out & turned off, until you can have it checked out. It sounds like you have doubt in the bubba that did the work. You can also let your state licensing authority & angieslist.com know about this contractor. State licensing authority would make note about problems with work done by this contractor, and will review when their license comes up for renewel if they have one. If they don't, they will fine the contractor for unlicensed work.
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Old 01-11-2011, 03:09 PM   #5
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Quote:

1) Is the refrigerant currently contaminated beyond repair? That is, are you recommending the refrigerant be removed and discarded before re-evacuating the system and installing all new refrigerant? No. The contamination/moisture will now be in the refrigerant oil which is mixed throughout the system but mostly in the compressor. Nothing can be done about it. We don't know in the LONG run whether moisture in the system will ruin scroll compressors and systems with R410. After 20 yrs we may find that the deep micron vacuum was not totally necessary. It is ABSOLUTELY necessary for low temp refrig systems but resi ACs are medium temp. The manufacturers are trying to prevent compressor failures/returns/warranty claims but we don't know if a bit of moisture is going to be lethal to the equipment.

2) Is the real issue the charge or the contamination? Would it be acceptable to have a technician,using subcooling, adjust the refrigerant, but continue to use the existing r410? I would.

3) How much moisture could have been in the lines? What portion was likely removed by the 30-minute evacuation? Is it possible that the existing line drier would remove the moisture in the line? Not likely there is much moisture unless you were in Florida/high humidity area. The drier should take care of it and his vacuum helped a lot.

4) Does any of this need to be done before next spring? Is the contaminated r410 currently damaging the compressor? No. What has happened to your system is not good but for the $500 or more to fix it I would leave it alone UNLESS you get a truly professional tech to fix it and those are RARE and how do you find one? We have good ones here but our airfare and expenses would be hard to justify.

Some of the other guys may disagree with my comments and that is fair and I don't have a problem with that.

Thanks again. I really appreciate your comments.[/quote]
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Last edited by yuri; 01-11-2011 at 03:12 PM.
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Old 01-12-2011, 01:09 PM   #6
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Condenser/Coil Install Questions


Quote:
Originally Posted by gregzoll View Post
If you think that it was not done properly, call another HVAC contractor that is reputable to come look over the system before firing it up for Spring. Just keep the Electric for the outside unit tagged out & turned off, until you can have it checked out. It sounds like you have doubt in the bubba that did the work. You can also let your state licensing authority & angieslist.com know about this contractor. State licensing authority would make note about problems with work done by this contractor, and will review when their license comes up for renewel if they have one. If they don't, they will fine the contractor for unlicensed work.

Thanks for your response,

Since I did most of the install, as I stated earlier, I take full responsibility for the limited work completed by the contractor. The service I received from him appears to have been less than ideal, but he was probably doing the best he knew and I am not trying to stick this on him.

Thanks.
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Old 01-12-2011, 01:39 PM   #7
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Condenser/Coil Install Questions


Yuri,

Thanks again for your expertise. Unfortunately I am still somewhat confused as to what you are recommending.

At a minimum, in the spring, I will have a contractor out and add or remove refrigerant using subcooling to get the quantity right. This would not remove any unwanted moisture that may or may not be in the system. I did not understand when you wrote above "I would", if this meant this is all you would do or would you do more?

The next, more rigorous approach, as I understand it, would be to try and remove the moisture from the system (that may or may not be there) and this is where I get confused. If the moisture has "become one" with the R410 refrigerant/oil, wouldn't the existing R410 need to be discarded? Or, does the existing refrigerant simply get pumped back into the condenser/compressor and the lineset and coil get triple evacuated?

Finally, what were you describing that would cost $500 (not including airfare and expenses ) that you did not think would be worth it? I probably would not be interested in spending $500, but I am interested in understanding what the next steps would be.

Once again, thanks for your comments.
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Old 01-12-2011, 06:01 PM   #8
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If there is moisture in the system then it's trapped in the oil. With the line sets open for three weeks and only a 20 minutes vacuum there probably IS moisture in the system . The only way to remove it now would be by replacing filter driers,possibly more then once. Many units have the drier inside the condensor so reclaiming the refrigerant to change the drier might be the only option. Reclaim,refrigerant and possibly several hours of vacuum to get,and hold, below 500 microns could be way more then $500. Probably looking at tripple that when all is said and done.
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Old 01-12-2011, 06:21 PM   #9
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Condenser/Coil Install Questions


Yep. The freon and oil are mixed together and the only foolproof way to clean your system would be to pay someone a lot of $$ and hrs to recover and (destroy/recycle) the existing freon according to local laws. Then with the complete system empty the drier needs replacing and a proper vacuum pulled after the drier is installed and a pressure test done and new freon added. $500 gets you a pumpdown, new drier and balance the system with existing freon and subcool method.
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Old 01-13-2011, 04:55 AM   #10
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Yep. Moisture can't be removed from POE oil by vacuum alone. Has to be done with driers.

How much moisture got in while the line set was open, is anybodies guess.

Probably little to no use to have system opened and new drier installed now, since it hasn't run yet(with exception of checking the charge). The current drier won't have been able to catch any of the moisture that may be in the system. Which most of it will be in the outdoor unit now.
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Old 01-13-2011, 07:20 AM   #11
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Condenser/Coil Install Questions


Thanks again to all that responded.

Since I did most of the work myself, I have invested a relatively small amount into my system. Even with Bryant's best Evolution furnace, Bryant cased coil w/TXV, Evolution tstat, 16-seer, Evolution compatible condenser, new, lineset, new supply plenum, new, upsized (thanks for the recommendation) return drop, other misc. supplies and paying my contractor, I have less than 1.5 grand in the system. This, of course, includes significant utility rebates and the government tax credit. Oh, there is also about 40 of my hours in there too.

So, given my limited investment, I plan to bring in a contractor in the spring to adjust the R410 using subcooling and run with it. Given the relatively high cost of the alternative (>$500), would anyone disagree with my decision? Would you recommend spending the $500 plus because you are convinced that the system is likely to fail almost immediately or for other reasons?

Thanks again.
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Old 01-13-2011, 09:28 AM   #12
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I would use it that way it is (after the rebalancing of the charge). I would suspect that less than 25% of the new ACs installed today get a proper deep vacuum pulled on them. LOTS of techs don't even own the gauge or a deep vacuum 2 stage pump and change the oil in it regularly let alone know how to use it or why. Time is money and most installers get paid a piece work rate so why should they spend extra time pulling a vacuum. Not a nice story but thats life. Therefore there are lots of systems like yours running out there for many years now and not falling apart. Same thing happens when repairs are done on units.
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Old 01-14-2011, 08:35 AM   #13
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Thanks, Yuri,

That's what I will do.
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Old 01-14-2011, 09:58 AM   #14
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I assume the evap coil when you purchased it was sealed and should have had a nitrogen charge, that is usually the way they come from the factory.
Was the coil still sealed until the refrigerant piping was connected to it?
The one problem I see was the line set cap missing or fell off. That should have been sealed immediately. Three weeks is a long time for it to be left open. Not only moisture but other things could have gotten into the line. Did someone check inside or blow the line out before installing it?
The condenser should have come with a charge so you know it was sealed.

The only time we ever use nitrogen purge is when there are runs of copper with several braze joints. If you were looking for a couple of joints being purged I don't think you would get enough copper nitrate to cause any problems. The drier would pick up most of it.
I don't think you will have any problems operating the system at this point unless there is a leak or if you have a super long run of line set and not enough refrigerant was added.

The only thing he was evacuating was the new line set and the evap coil. If he did it for 30 minutes and it pulled a deep vac. I think you will be alright
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Old 01-14-2011, 10:12 AM   #15
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Yes, the coil was sealed up to the point it was brazed. The lineset is 25-feet, so I do not think it would be considered extraordinarily long. And, no, the lineset was not blown out (I am feeling dumber by the minute). When I do this again in 15-years or so (assuming it lasts that long), I will be so much smarter. Thanks for your comments.

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