Room Air Conditioner Odors

What might cause a room air conditioner to put off a fishy odor? My room air conditioner (large room) has always been filtered properly, seems to have adequate draining to the outside and otherwise works fine cooling-wise. All of a sudden one night, it started putting off this rotten fishy type odor and we can't figure out what's causing it. We've had this unit (from Sears) for probably 5 years and it's worked fine up until now. Sometimes in the past, it would put off a musty odor and we'd clean the filter and all would be well but now, it's more than we can handle once it starts smelling like that. It's running for probably 20-30 minutes just fine before it starts putting out that smell (even though it operates fine where temperature is concerned). Also, it runs fine in 'fan' mode with no odors for extended periods of time. thanks for any ideas...
John
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snipped-for-privacy@lycos.com wrote:

Dead something in the condensate tray. Take it outside, remove the covers, gently spray both coils and the tray with a hose. Use a chopstick to poke loose any caked up crud. You might need coil cleaner after that, and another rinse, but you might get away with using dish washing liquid mixed with warm water sprayed from a garden sprayer.
Usual warnings - stay clear of the electric components, let it dry before plugging back in, don't stick your finger in a socket, etc.
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Either that, or the condensate tray is not draining properly. That is, it might be DRAINING, but only after it reaches a certain level. So what's left sitting there is stagnating. -Dave
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Newer window air conditioners have a pool of water in the bottom which is always there. The fan in the back splashes the water onto the coils and this helps it cool more efficiently. This standing water can get things growing in it. I just pour a little bleach in the side of the air conditioner outside and this kills whatever is growing in the water.
Then the fishy smell goes away. I only need to do this once or twice a year.

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Every window A/C I've seen has done this; it's not just newer ones. In fact, the newer (3-4 year old) units I have don't accmulate much water on their own. I can add a quart, but it doesn't last more than a few hours (then again, we're seeing 100F - 102F highs at the moment).

I can vouch for that, having found thick layers of mold growing in the old A/Cs I replaced...

Bleach is corrosive to aluminum. I've been advised to use hudrogen peroxide, which seems to work without risking damage to the coils.

I've never noticed a fishy smell, just bits of black mold getting thrown out of the vents. (The insides of both coils of one window unit got clogged with it--badly.)
Gary
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Gary Heston snipped-for-privacy@hiwaay.net What do you call two SUVs colliding?
Poetic justice.
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Uh, do you live in New Orleans by any chance?
Don
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Thanks for the replies all. Turned out to be a plugged drain and washing out the tray real well that cured the problem. thanks again. John
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