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Incorrect draining, rusting, and green corrosive on coil after regular cleaning

Incorrect draining, rusting, and green corrosive on coil after regular cleaning


  #1  
Old 04-20-13, 07:09 AM
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Angry Incorrect draining, rusting, and green corrosive on coil after regular cleaning

Greetings to the members of this forum, this is my first post, hoping to get some help. I am an American expat living in the Philippines, and I bought a "Carrier Mini" window air conditioner for our bedroom.

The unit recently turned 6 months old and I hired a local service to come and clean the unit as a regular/preventative maintenance. There were previously NO PROBLEMS with the unit.

That changed after the cleaning. These technicians were incompetent and made several mistakes including fitting the cover on wrong, screws in the wrong place, hi/lo fan switch reassembled upside down. They did a rushed and sloppy job.

Now, 10 days after the cleaning, I opened the unit and I noticed the bottom brass coils have turned a corroded green and the bottom screws have become rusted along with some of the metal of the frame. There was water sitting in the bottom of the unit.
I also noticed that water does not drip from the drainage hole as it used to before the cleaning. It seems to be running out from some other place under the aircon.

I attached images to this post to show the problem.
I would really like to know what's wrong with the unit, what these inept techs did to my 6 months old air conditioner, and how it can be fixed.
Any help is greatly appreciated. Thanks.
 
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  #2  
Old 04-20-13, 07:35 AM
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1. As a Gringo I would not bring contractors or service people into my home unless absolutely necessary. You don't want what you have (possessions) known to others and you don't want others to learn your schedule or when you will not be at home.

2. Is cleaning of your unit necessary? If it is, judging by your pictures, you are easily capable of doing it yourself. Clean the inside air filter. Look at the coils outside and if they are clear/clean don't touch them. If the bottom tray is dirty rinse it out with water. If you have trouble with mold or other growths in your climate rinse the tray with chlorine bleach & water. Make sure the drain hole is clear of debris and make sure the unit is pitched/sloped so the water runs to the drain hole.
 
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Old 04-20-13, 08:54 AM
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Thanks for the reply Pilot Dane. So the green color is mold? Caused by a blocked drain hole?
And to clean the green color, I should use bleach?

Yes I will definitely do it myself next time.
 
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Old 04-20-13, 09:57 AM
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It appears to me that the green color is normal oxidation that happens to all copper under the right conditions, not mold. Most mold is black, not green.
 
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Old 04-20-13, 10:29 AM
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The green is the copper tube oxidizing. It oxidizes more on the bottom tube because it stays wet much of the time. Mostly because the water from the tubes above drip down onto it and could be from the tray not draining properly. Don't try cleaning or removing the green. Copper corrodes slowly and doesn't do any harm and you may damage something if you try getting into the nooks & crannies to clean it up.
 
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Old 04-20-13, 10:31 AM
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"It appears to me that the green color is normal oxidation that happens to all copper under the right conditions, not mold. Most mold is black, not green."

Thanks for the reply Tolyn Ironhand, I'm just trying to get some definite answers and a solution so I can correct it myself. I hope others will reply too.
Question: If that is normal oxidation, then why didn't the other coild turn green?
And why did part of the metal of the frame turn orange with rust? and some of the screws also have rusted, particularly the ones in the bottom of the unit.
 
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Old 04-20-13, 10:41 AM
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Water flows downhill so things at the bottom tend to stay wet the longest. Copper oxidizes green while steel rusts red. The coating on some screws and aluminum will oxidize white. In a tropical or coastal climate especially where the AC runs often there is not much you can do to prevent the rust and corrosion except keeping the unit somewhat clean. In the end it's generally a loosing battle so I would not waste too much time cleaning or worrying about it.
 
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Old 04-20-13, 10:56 AM
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Thanks, Pilot Dane, the problem is that in the 6 months previous to the cleaning, I never saw any oxidizing or rusting, it was only after the cleaning, this occurred.

It was suggested in another forum that "most likely when they slid it back into the housing the tilt of the housing was moved. this would cause the unit to not drain properly."
Although, I don't know, it seems it might be true, but I have no knowledge how to check the housing tilt or correct it.

I would also like to find a coil cleaner here in the Philippines to remove the green color, I want to re-sell the unit in a few months and need it to look good. Since it's only a few months old, I would really like to avoid the rust and corrosion if I can.
 
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Old 04-20-13, 04:07 PM
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Don't worry about the green color on the copper tubing. It's natural and cleaning it will do more harm than good.

Generally the drain holes are located on the outward side so a slight angle sloping away from your house or apartment. If you don't have a level simply pour some water in and see which way it drains. When in doubt drain water away from the house.
 
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Old 04-20-13, 11:03 PM
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Taking another look, it seems maybe the tilt is not the problem, because water is dripping from a drain hole in the back of the unit. However the drain hole its dripping from is a completely different one than the drain hole it was dripping from before the cleaning, and the original drain hole is dry. Why did it change drain holes?
 
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Old 04-21-13, 09:03 AM
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NEW INFO -

Thank you to the board members who continue to help me with this, I am lacking severely in competent advice.

I have removed the cover of the air conditioner again, was trying to see why it won't drain. Unfortunately I don't have the correct size screwdriver to unmount it from the housing.

BUT I was able to see that the unit is basically SITTING IN A PUDDLE OF WATER.
When I ran my hand on the bottom in the water, I also noticed that it feels like there is more than water there, there's some sort of slimy consistency. When I scooped some of it up and pulled it out, it looked like a thick mucus dripping from my hand. Anybody know what this is?! Maybe this is the stuff which has clogged the drain hole and the reason why the unit won't drain.
 
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Old 04-21-13, 12:17 PM
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Don't worry too much about the slime, apart from it blocking the drain which is a very common problem. More so on larger refrigerated cabinets. As for why there is more oxidisation after the cleaning, well it isn't unheard of for not so nice people trying to make an extra buck or two by causing problems that might take a while to show up. You have to call them back, they "fix" the problem and you get to give them more of your hard earned cash!
I know you said you want to clean it, but I wouldn't really recommend it. A little too aggressive in one spot and you can very easilly create a hole of a weakpoint in the pipes. The unit leaks all the refrigerent and then you need to pay someone to hopefully fix it correctly. When done correctly it can be quite a costly job due to the time involved.
I don't know about you guys over the water but we've just been hit with a lot of new laws over here which can slow the job up. If you really feel the need to clean it then the most I would recommend it one of those green coloured felt type cloth things for washing plates etc. A small and thin brass brush can be used in the trickier areas. Stay away from sandpaper or anything like that
 
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Old 04-21-13, 01:22 PM
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Ketchup will clean the copper right up, but it really doesn't matter about the oxidation. It will not harm operation in any way.
 
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Old 04-22-13, 03:55 AM
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YES.

I was able to disassemble the unit enitrely and clean up the water and dry out the bottom tray completely before assembling it again. There is no documentation or mention of sloping it downward. In the installation instructions, its level. But inside, the bottom tray or housing (not sure how to call it) has a sort of sloping path for the water to run a course to the drain hole. If its not too backed up or overflowed, it should work. My guess is that the cleaners didnt dry out the unit before assembling it, and just put everything back wet.

So after drying it out, I reassembled it, re-installed it, and turned it on and it actually worked. Amazing.

But I still have a small (or maybe large) problem ---
If I touch a screw holding the covering I get a small shock. I checked the ground wire, and it seems fine and correct. I don't know why I get a shock when I touch any of the screws holding on the cover.
 
 

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