Thread: AC UNITS DAMAGED BY BUILDER'S BRICK CLEANING ACID

I posted a similar thread a while back but this bears repeating as I am seeing this more and more during the rush of construction that is occurring in the Dallas area. Damage from acid being blown by the wind into the AC condensers.
This is the text I put in my report:

"Both outside AC condenser units have corrosive damage from contact with an unknown caustic chemical. The most likely chemical is an acidic cleaning agent used to clean the bricks during the final stages of construction. There are several cleaning agents that can be used; however Muriatic acid (hydrochloric acid) is the most common. The outside AC unit’s internal components, copper lines and aluminum coils have etching and pitting damage from contact with the acid. The etching and pitting is caused by the acid dissolving the metal. Once corrosion starts, it does not stop. Eventually the corrosion will cause the lines to leak Freon, which will cause the unit(s) to stop cooling. This may not happen for several years, however eventually the corrosion will cause leakage. In the opinion of the inspector, both outside AC units should be replaced due to the acid contact and damage and the long-term negative effects of the acid corrosion on the coils."NEIGHBOR AC 2.jpgNEIGHBOR AC 1.jpgIMG_8273.jpgIMG_9204.jpg

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Originally Posted by Gene South

I posted a similar thread a while back but this bears repeating as I am seeing this more and more during the rush of construction that is occurring in the Dallas area. Damage from acid being blown by the wind into the AC condensers.
This is the text I put in my report:

"Both outside AC condenser units have corrosive damage from contact with an unknown caustic chemical. The most likely chemical is an acidic cleaning agent used to clean the bricks during the final stages of construction. There are several cleaning agents that can be used; however Muriatic acid (hydrochloric acid) is the most common. The outside AC unit’s internal components, copper lines and aluminum coils have etching and pitting damage from contact with the acid. The etching and pitting is caused by the acid dissolving the metal. Once corrosion starts, it does not stop. Eventually the corrosion will cause the lines to leak Freon, which will cause the unit(s) to stop cooling. This may not happen for several years, however eventually the corrosion will cause leakage. In the opinion of the inspector, both outside AC units should be replaced due to the acid contact and damage and the long-term negative effects of the acid corrosion on the coils."NEIGHBOR AC 2.jpgNEIGHBOR AC 1.jpgIMG_8273.jpgIMG_9204.jpg

Getting back to the "throw 'em up quick" with whatever labor shows up. One of the benefits of the downturn and slower market was a bit more care and knowledge in construction, IMO.

Do you have a basis for the statement "Once corrosion starts, it does not stop."?

Originally Posted by Jim Luttrall

Getting back to the "throw 'em up quick" with whatever labor shows up. One of the benefits of the downturn and slower market was a bit more care and knowledge in construction, IMO.

Do you have a basis for the statement "Once corrosion starts, it does not stop."?

Corrosion takes on different forms. It is an ongoing electro-chemical process . Like rust. It does not decide to just completely stop. There are many papers on this. Aircraft manufactures focus on aluminum and copper corrosion and the weakening of the metal.

Originally Posted by Gene South

Corrosion takes on different forms. It is an ongoing electro-chemical process . Like rust. It does not decide to just completely stop. There are many papers on this. Aircraft manufactures focus on aluminum and copper corrosion and the weakening of the metal.

Yeah, I get the process for corrosion... but with an acid corrosion on copper, seems like the corrosion would stop once the acid is used up or neutralized by enough water.
If copper corroded naturally like iron or aluminum it is easy enough to say "yep once it starts it won't stop but with copper and acid it is a different chemical process, not really natural oxidation as far as I know.
I call out corrosion on drip pans all the time since once the galvanized coating is consumed, oxidation will continue even without liquid in the pan, even damp air will continue the process.

For example, we use acid flux to solder pipes and we sometimes see the continuing corrosion if they did not wipe the joints or just used too much. I'm just wondering if there is some process that I am not familiar with to cause me to worry more.
Of course if they get a home warranty claim you can bet that the corrosion will be a "non-covered" condition that caused the system to fail.

Originally Posted by Gene South

Eventually the corrosion will cause the lines to leak Freon...

I would get rid of the word "Freon" and use "refrigerant" since Freon is a brand name like Kleenex is to facial tissue.

Originally Posted by Steve Payson

I would get rid of the word "Freon" and use "refrigerant" since Freon is a brand name like Kleenex is to facial tissue.

Not only that, but newer units don't use Freon as the refrigerant. I believe the brand name for R410A refrigerant is Puron (at least started out as Puron).

While I understand what you're trying to convey, I would drop the whole "acidic cleaning agent" portion of the narrative.

Unless you witnessed the application of the acid, it's just a guess (based on experience, I know).
The root cause of the corrosion isn't as relevant as the fact that the equipment is corroded right now.

Dom.

I washed many masonry walls and back then it was one part muriatic acid to nine parts water. It is not sprayed on. You apply it sparingly. you do not want acid leaching into the clay or degrading the fresh mortar.
.
Many jurisdictions ban muriatic acidfrom being used to prevent new masonry building bloom. Now masons use new masonry cleaners.
Hope that helped.

myth busted...probably

before this starts a non-issue copper patina reporting trend
i had to test
i sprayed copper pipe with HCL/muriatic acid
allowed to dry
CLR on q-tip used to clean instead of baking soda & water...the Bride says her cooking supplies are above my pay grade

unless the piping is pitted/physically damaged have builder apply an approved neutralizer and rinse off patina if any is left behind
cu patina.jpg

Originally Posted by BARRY ADAIR

myth busted...probably

before this starts a non-issue copper patina reporting trend
i had to test
i sprayed copper pipe with HCL/muriatic acid
allowed to dry
CLR on q-tip used to clean instead of baking soda & water...the Bride says her cooking supplies are above my pay grade

unless the piping is pitted/physically damaged have builder apply an approved neutralizer and rinse off patina if any is left behind
cu patina.jpg

I agree about the narrative green patina.
Sorry for going off thread.

Copper piping, type M, or L in most residential homes have light corrosion, that is what it is, from plumbers not wiping away the residue flux and freshly appealed solder.
Corrosion Pitting is what should be documented on copper piping, and broken solder bonds on hvac systems piping.

Getting back to the thread.

Muriatic acid is a highly reactive liquid acid, and one of the MOST DANGEROUS CHEMICALS you can buy for home use. With the exception of some plastics, muriatic acid can damage most anything it touches, including clothing, metal, and skin! It emits a suffocating odor that can quickly burn the lining of the nose, throat and even the lungs.
http://www.naturalhandyman.com/iip/infxtra/infmur.html

When I use to solder copper seams on standing or other copper or galvanized locked roofing seams and applied muriatic acid to etch away a layer on the metal and factory applied coatings the vapor would take your breath away.
I do not think a it wives tale and I would avoid using a highly reactive liquid acid when testing for HVAC or other pipe leaks.
Soapy water will provide a nondestructive test.
Just my opinion.

Sorry for the edit.
Been on the water fishing this long weekend and I am exhausted from the sun and wanted to reply to the thread.

I asked about the effects of hydrochloric acid (Muratic acid) on copper refrigerant piping and submitted the following questions to ACCA (Air Conditioning Contractors Association)

- How bad is that for the copper refrigerant pinping?
- Is there an easy way to neutralize the acid?
- Is it necessary to neutralize the acid or does rain dilute it sufficiently, or does it simply dry out and basically become a non-issue?

I will post the answer when I receive it.

Here is a document on copper corrsion.pdf and hydrochloric acid.

Originally Posted by Jim Luttrall

Do you have a basis for the statement "Once corrosion starts, it does not stop."?

Hey hey, my my, I concur.
Neil Young concurs as well, Rust Never Sleeps (Full Album) - 1979.
I think his thesis went; It's better to burnout than it is to rust.
neil tried to describe the sound of rust through his harmonica.
Brings me to tears every time him play.
Neil was not very technical mind you, but he was not a deep thinker.

Originally Posted by ROBERT YOUNG

Here is a document on copper corrsion.pdf and hydrochloric acid.

Robert,

Would you summarize that for us?

(I couldn't when I found it.)

Originally Posted by Jerry Peck

Robert,

Would you summarize that for us?

(I couldn't when I found it.)

It is about the variation of the copper weight loss after immersion for 48 h. in the acid solution.
Poor example.
I thought it would be entertaining read for someone that could narrate a final conclusion better than myself.
Jerry, members, my apologies.


IMO refrigerant leaks cause similar corrosion.
I see that type of corrosion in air handlers.

Look at image #3.
1: The foot of the compressor baked on paint has errored.
2: The brazed fitting at the compressor have pinhole leaks.

Just my take on it.




1.JPG

Originally Posted by ROBERT YOUNG

It is about the variation of the copper weight loss after immersion for 48 h. in the acid solution.

Robert,

No need to apologize - when I found that and read through it, I kept thinking "Huh?", so I went to the Summary and ended up with "Huh? What are they saying is the long term outcome? " ... thus I sent my questions to ACCA.

I'm not a chemist by any thinking - maybe someone here is/was?