Air Conditioner Mystery

[bajaespuma]

Maybe somebody here can help me solve this problem. I have 4 Sharp brand window AC units that I remove from their windows for storage each year at this time. All the units are mounted under eaves so they are never directly exposed to the elements.
They are all the same age.
This year, I hosed off the backs of the units to clean the radiator fins. On one of the units, as I hosed it off, 1/3 of the aluminum fins disintegrated from the spray. It looked like what happened to the deck of the Nostromo when they tried to remove the Alien face-hugger from poor John Hurt's face:

 

[bajaespuma]

I had done the same thing to the other 3 air conditioners, but when I sprayed this last one, the damage happened instantly. The others had little to no damage. One other unit had a little spot where the aluminum vanes disintegrated a little bit:

 

[bajaespuma]

I'm assuming that with more than one third of the radiating vanes gone, that air conditioner is done. I'm usually good at figuring these things out but this time I'm stumped. Usually I walk around the house in the summer to inspect the backs of the AC units to make sure that no bird or squirrel is trying to nest inside them. Remember that all of these units were installed underneath roof overhangs so they were never in the direct line of rain, and it's a fair assumption that air conditioners are made to withstand normal exposure to the weather.

Any ideas?

 

[whirlaway]

Thats Strange!

Copper and aluminum dont do very well together,could be a factory defect also have you used a sodium based lawn product? Are you near the ocean? This usually happens around here on a very old window units.Im about a block from the water.It just turns to powder and then starts to eat at the copper,the last unit I had to go was a 1949 Mitchell,it had just started losing freon12 the coils were half cold.You should still be able to use your units a few more summers. Bobby

 

[davetranter]

Corrosion

I'd just noticed that, too, Whirlaway. The fins appear to be aluminum, the tubes copper.... That's good for electrolytic corrosion if they are kept damp. Is this unit near a boiler flue, bathroom extractor flue or similar?? If the tubes ARE copper, you could try soldering new (copper) fins on to them, such as from an OLD auto radiator, or even a modern computer.

All best

Dave T

 

[tomturbomatic]

I'll bet it's the salt spray. This one either catches more of it or is in a position where less of it gets flushed away by rain. GE spine fins in Florida used to look like they had undergone a Nair treatment they would get so smooth.

 

[bajaespuma]

Thanks for the responses

Salt spray is a good hypothesis because I live less than 1/2 mile away from the coast of the Long Island Sound, except for a couple of facts.

1. The air conditioner in question was mounted on the North side of the house, away from the coast. There were 2 other air conditioners mounted on adjacent windows on the same side of the house, neither suffered any damage and neither 6 feet away from the air conditioner that corroded.

2. The air conditioner mounted on the side of the house that faced the Sound had no corrosion whatsoever.

The copper/aluminum theory is elegant and I'm going to look at that as well but, if that happened a lot, wouldn't that be ridiculously negligent of the manufacturers to continue that technique?? It's not like this is an American brand.

For the record, all air conditioners have always been removed from the windows and stored inside the house during the Winters.

I'm beginning to think that maybe one season some critter or another might have made a nest inside of the unit that wasn't visible from the outside and attached it to the fins with some kind of corrosive substance (again, the ALIEN)and I never saw it until it just disintegrated away. I live enough in the country that I'm always banging on the units when I here creatures cavorting inside them. Small price to pay for nature, but I'd rather not have to buy new air conditioners before their time is up.

 

[rustyspaatz]

It looks like a central Air condenser unit I had covered for the winter.

But my issue was caused by a mouse that got in, made nest and literally ate some of the alumin off, AND
even ate into the cheap aluminum tubing. Just enough to cause all the Freon to leak out.

God-daxx-blankety-blank-XXXX-mother-fxxxen-blankety-blank-son-of-a....

 

[tomturbomatic]

AC units have been using copper and aluminum tubing/fins ever since they started making them. Maybe you should put some hardware cloth cages around them to keep out tenants.

 

[yogitunes]

my central air unit did the same thing this past Summer, the repair guy said its from the dogs lifting their leg on it, that could be true....I have had dogs since I got the house, and its been ten years for this to show up?...but in your case, this doesn't help

look Ken, it could have been set to 'self-destruct' by you, for reasons unknown...

....we set down on LV426, on companies orders to get this thing, that destroyed my crew, and your expensive air conditoner!.....

it could be an ALIEN invader......its what we call a 'Shake and Bake' colony!....

and were in the wrong forum to discuss how that embryo was placed in ones' throat!

Ken, we have a date.......grab a pizza one weekend, and watch every single Alien movie there is, in order......I have them all on DVD!...we don't need volume, I know each word by heart.....lol

 

[bajaespuma]

No dog peed on my unit, but a mouse in the house

was a definite possibility. A family of mice was responsible for the demise of my Parents' beautiful 1953 J408 "Liberator" range. Made nests out of the insulation and chewed the wires to most of the burners.

Martin, have you seen the uncut edition of the first movie with the sneak peek of the adult alien and the "transformation" scene with Dallas and Brett? It's a date!

I saw "Alien" when it opened in 1978 and I have to admit that it scared the poop out of me. I almost had to leave the theatre when Dallas went into the air vents. Glad I stayed to the end; first movie with a character that acted as if she had, in fact, seen a horror movie before in her life. Poor Veronica Cartwright; no matter what movie she's in, she always seems to get the worst of it.

 

[yogitunes]

I didn't know there was an uncut of the first movie......and wished I did see it, that was the hard part of getting a full view of the Alien....

now I do have both versions of Aliens.......I like the extended one....gives more details.....

I got to see a lifesize Alien at a StarTrek convention here in Atlantic City, I think it was 1991 or 92.....and missed a photo op of being inside of the power-fork lift and the Alien grabbing at you!....

I wanted to rent the costume for Halloween, and just go to the schools and scare the kiddies......theres a 8 month reserve needed for that puppy!....

is it possible to do an Alien wash-in?

 

[kb0nes]

Ken,

Indeed that is an odd thing to have one area of the condenser on one of the four identical units you have literally disintegrate.

I think we can rule out anything that is common between the units.

Galvanic reaction between copper and aluminum can occur, but its unlikely. If it were a common problem why are most all AC coils be made from copper/aluminum? Also why didn't the rest of this condenser or any of the others fall apart too?

Salt air was breathed by all 4 units also. And again it would likely be more uniform, although Tom had a point about it possibly being rinsed away better over part of the coil. Still the other units would likely act in a similar manner.

My hunch is a manufacturing defect. Something was different about that part of the coil. Perhaps there was a chemical used that wasn't rinsed or neutralized on that unit. I don't know if they anodize the completed assemblies but if they missed a step maybe.

I agree that this AC is likely now a parts unit

 

[bajaespuma]

Acheronses Linguafoeda

Yeah Phil, that's what I figured. At best the efficiency of the unit would be ruined by the lack of so many fins. On closer examination of the fins it's clear that they're made from a very fine gauge of aluminum; not much thicker than household foil. I suppose that it would take very little to make that metal oxidize and weaken. I've had the units for over 10 years so I'm ruling out manufacturing defect because I would expect such a thing to happen much sooner. Right now I'm going with some kind of corrosion from some unwelcome critter that made a home inside the unit when I wasn't paying attention. The Alien.

Martin, the version of the first Alien movie that I'm talking about is sometimes known as the director, Ridley Scott's cut. A scene that I've heard about but have never seen(it may have been lost forever on the editing floor) is one where Parker (the magnificent Yaphet Kotto) goes down to stores to recharge the flamethrowers. On the way he encounters the Alien and discovers that it's right next to an air lock. He contacts Ripley via com to get her to open the airlock. Just as she's about to hit the switch an alarm goes off and scares the creature away(running into Parker and injuring him in its rush). I suppose they cut this scene out because it would implicate the real villain too soon. You can see the lead-up to the scene in all of the versions out there, but it goes nowhere.

I was fascinated by the biology of the creature. It's been messed with in all of the sequels. It was O'Bannon and Shusetts' genius to imagine what would happen if a creature like an fire ant or a hornet suddenly became human-sized but retained insect speed, generation and strength. They also "borrowed" from a late 1950's "B-" space movie for the plot (a "Chiller Theatre" regular), but we forgive them.

You might enjoy a book I was given years ago about H.R. Giger's artwork for the movie. I remembered him from my prodigal "head" days. You might find it on line from Amazon but the drawings/paintings are amazing and there are some behind the scenes photos from the movie.

View attachment bajaespuma++11-15-2013-19-17-10.jpg

 

[whirlcool]

Are there squirrels in your area that may have walked across the unit? I have heard that their urine will do this to a/c units.

Our American Standard A/C unit has fins that can be destroyed by dog urine. When the installers were putting in our unit two years ago they warned us not to let our dogs get too close to the units. If they urinated on the outside compressor it'll dissolve the fins. We put up a little fence about 3 ft tall all the way around the unit about 3 feet out to prevent that from happening. So far, no problems.

 

[rustyspaatz]

Yeah, it does sort of look like something was spilled or sprayed on it.
Was there food placed on top the feeder that would allow the squirrel to sit in just the right place and eat, and when they eat they usually do other things.

Could something/someone have spilled or sprayed something on it when it was in storage?

Cat pee? Do you have homeless people living in your garage that might have peed?
A drunk friend? A vengeful neighbor? A prankster significant other?

You also mentioned that these are under the eaves. Could it be that when it rained, water from a leaky gutter leaked down on it? And could it be that the paint is wearing off the gutters? Maybe the residue from those got on these, and created a reaction?

 

[yogitunes]

thanks Ken...I will re-check on that part of the movie, I might have that version and didn't select it....and will check out the book as well...thanks......

I too was scared to watch the first Alien on HBO at night time......that one didn't give me nightmares like number 2 though.....everytime I was put under for surgery, I woke up from dreaming that movie, screaming and full of sweat, they soon learned to tie me down after that....

I am a big fan of Sigourney Weaver(Ellen Ripley...also the name of my second siberian)

big fan of SciFi movies of anytype.....

 

[whirlaway]

Massive Electrolasis

Excuse my spelling,it seems as though where the corrosion appears,according to the pic,is a dark green almost mold like color.Could they have been clogged or did that unit experience high voltage at one time.I know here on the coast in Va,the humidity is so high GE units dont last here hardly at all.They have those like coiled ones in the back case and they corrode to nothing in no time.If the unit still cools keep it on the cooler side of the house,it will probably be OK.Its so odd! Most units start at the bottom and you have to remember,they stay wet all of the time from water being thrown on them by the fan.You dont have a well do you? That could be throwing water on it. You might can tie wrap something make-shift to them also,Well Whatever Good Luck

 

[arbilab]

Aluminum seems like this inert metal that just sits there. Aluminum is actually very reactive. Mercury dissolves aluminum foil in a matter of seconds. Yeah, mercury, another metal that seems to just sit there (OK, it rolls around some).

So, what? A cat ate tuna contaminated with mercury and peed on your AC? Not going that far. Just that aluminum, especially as thin as sometimes applied in AC finnage, is nowhere near as sturdy as it may appear.

Have to admit, I have never seen that degree of deterioration. or ANY appreciable deterioration, of AC aluminum finnage.