My outside air conditioning unit needs a Karen Silkwood shower
June 25, 2008 8:56 AM   Subscribe

Help me de-gunk my outside air conditioner.

Last year, I had a great guy replace my air conditioning unit in my five-year-old house. Being not the best homeowner in the world, I had no idea there was a vast series of weekly and monthly steps to be done to keep things nice (with the house in general), which led to me spending three grand putting in a whole new unit.

The guy told me that my outside air unit needs to be cleaned regularly to keep debris (leaves, bug bodies, crap in general) out of the blades surrounding the fan. He said the occasional high-pressure spray down with an outside garden hose would do, and that's what I've been doing. But he also mentioned that every 5 years or so, the blades in the vents would get so clogged I should do an "enzyme clean." He specifically said it was for the blades on the outside unit, NOT a duct cleaning or coil cleaning. Well, I tried calling the guy this summer and his number is disconnected, and googled "enzyme clean" and all I get is services for cleaning air ducts.

Does anyone have any experience with this? I looked at my unit yesterday and it looks pretty gunked up and I would love for it to be running as efficiently, cleanly and coolly as possible now that the 100+ degree days have started. Ideally, I would love to just do it myself, if that were possible, and he mentioned you could buy the product yourself and do it without professional help or hire an HVAC person to come and do the cleaning for you... but now I don't know who to call or what to ask for. If it helps, I'm in Dallas.
posted by Unicorn on the cob to Home & Garden (5 answers total) 1 user marked this as a favorite
Here is a bit of info on coil cleaning; despite what you were told, you are describing coil cleaning; the coils run through the fins around the fan. I have a friend who does HVAC work and he prefers acid based cleaners depite what the article I linked said; he also says that in general if you regularly hose down you outside coil you won't need to clean it very often.

It may be that by "coil cleaning" he was referring to the inside coil (also described on the page I linked to) which I would be more likely to leave to a pro.
posted by TedW at 9:10 AM on June 25, 2008

The only time we used anything harsher than a biodegradable pressure washer soap solution in conjunction with a pressure washer was if the coil had a scale build up. That's pretty rare if you don't have hard water somehow getting on the unit on a regular basis.
posted by Mitheral at 10:33 AM on June 25, 2008

I clean our filters every 3-4 weeks, and at that time spray off the outside unit.
Besure to spray head-on with the fins, so they do not get bent from the water. I just use the garden hose with a spray attachment no pressure washer.
We've been in our house for about 2 1/2 years. It was built mid 60s. Outside unit was changed in the 70s-80s and the inside unit was changed in the 90s. We've worked more on getting our house better insulated and ventilated (new windows and attic ventilation and insulation). If your house is around 5 years old then you should not have to deal with that stuff.
Clean/change your filters regularly and spray off your outside unit at the same time. Adjust frequency if filters/outside unit are super clogged. It will/should become habit. If your outside unit gets shade that helps, but it also needs good airflow so no bushes upclose smoothering it.
If you have constant exposure to cottonwood drift you might want a coil cleaner.
I live right outside of Dallas.
posted by sailormouth at 11:10 AM on June 25, 2008

Response by poster: See, that's the thing, I live on the lake and the cottonwood drift thing is an issue. (Imagine the forest in the movie Legend with all the white crap floating in it and that's my neighborhood for a while in the summer). I actually have a creek bed behind my house full of the stuff.

Looks like I might just be better off calling somebody... with my luck, I'll break something. Thanks everyone for the responses!
posted by Unicorn on the cob at 3:02 PM on June 25, 2008

Best answer: Go to the hardware store and get some screen material and wrap it around the outside unit for the cottonwood season with bungee cords. When it clogs, just wipe it off with a broom. Or remove it and spray it out.

TO clean the unit good, pop the top off and squirt water from the inside out. That's because you are spraying against the airflow and anything that's lodged in there will get unlodged by the reverse flow of your sprayer.
posted by gjc at 6:58 PM on June 25, 2008

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