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Mold Prevention in A/C Unit

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Aug 05, 2013, 08:41 AM
Mold Prevention in A/C Unit
I live in South Florida where it's very warm and humid. My A/C technician charged me a lot of money for spraying my home's A/C air intake with some bactericidal/fungicidal treatment because he found some mold underneath the air handler. I don't want to go through this again so I put a DampRid bucket to control the humidity inside the closet where the air handler is. I also looked up in the web and and found some products (Moldex, MoldStat) that work with this kind of problem. Can I spray a product such as this (maybe monthly?) in the closet to avoid mold growth?
Aug 05, 2013, 12:07 PM
If you can get access to the coils in the air handler, spray some dilute bleach on them. it will drain into a pan below them and kill any mold there as well. you might also have a PVC fitting that allows you to pour some of the bleach directly into the pan, If you do, it's a good idea to do this periodically
Aug 05, 2013, 01:14 PM
make certain your drain line for the pan is fully open and flowing well. I am very sorry to report the maintenance manager taught me something when I was working there in the 80s... said take this ice machine cleaner and sports bottle and rod out the room ac unit drains.

well, that's phosphoric acid, and it ate away all the galvanizing in seconds, so the pans and drains showed rust within months. as if they hadn't learned already about acid and drain lines. sheesh.

if the lines are clogged with lint and growths, it's generally safe to use an ammonia cleaner if the stuff doesn't gag you (asthmatics, take note.)

but if the drain lines is not flowing, you will spill water over, and definitely grow mold.

ideally if the coils are accessable, you should very lightly pick off or brush with the fins using a chip brush to get any lint off. and start replacing filters in that case, good disposeables. lint carries biologics like skin flakes and stuff, and stays wet from condensate, and thus you have moldy cooling coils.

sig: if this is a new economy, how come they still want my old-fashioned money?
Aug 05, 2013, 10:07 PM
Thanks for the info. I pour bleach down the a/c drain every month and so clogged drains. I looked underneath the air handler and only saw a few spots of mold which I sprayed with Moldex and let dry before inserting the filter. I definitely will have to pay closer attention to this.. . Not only because of the mold but also because of my pocket. I think I fell for a scare tactic. Ill continue to monitor the DampRid as it absorbs moisture and adds another layer of protection.
Sep 06, 2013, 10:19 PM
very humid in fla. you have a air leak. fix the leak and the condensation will stop. then the mold will go away.
with unit running, all doors closed. run your hand over the unit. and find a change in temputure or air flow
cold air blowi9ng on a warm surface causes condensation.
also...check the drain line is pitched so that the water will run away from unit.
you said that there was water/mold under the unit? ck that the internal drip pan. its under the copper coil
his draining.
the drain the pipe wet? if so, insulate the pipe.with rubatex..rubber insulation. and use contact cement to seal the insulation to itself. again, cold water in drain,.. pipe sweats.

finally.the unit should be sitting over a drain pan if its a horizontial unit. pan should not hold water, it should be pitched twards the drain

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