For years, technicians have told me to pour bleach down my a/c condensation
line once or twice a year to prevent bugs and other things from clogging it.
Just had an annual preventive maintenence check and the guy told me that
vinegar was the best way to go while bleach was bad. Any one have insight
White vinegar is pretty good stuff.
If you sprinkle baking soda down a drain & then pure white vinegar down
it, it foams violently & is supposed to unstop them.
I would then use boiling water to flush it.
I plan to try it on my kitchen sink drain lines. - udarrell
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Does this make sense? You're putting the acidic vinegar with an acid
neutralizer. Makes a nice show but the net result is neutral (unless
there is a lot more vinegar than the sodium bicarbonate can zero out. For
a ha-ha you can always call the misses and "Look honey. The sink has
Not really...what did he say was "bad" about bleach vis a vis vinegar?
Vinegar is a mild acid, bleach is essentially a solution providing free
chlorine as an oxidant.
IMO, bleach is far more effective in the killing of the mold, etc.,
that tends to grow in condensate drain lines although vinegar will
certainly help. Assuming flush the line after treatment (which I would
do with either) don't see any thing that should be a real problem w/
using ordinary household bleach.
Only real thing I can think of is bleach might be a little more likely
to kill any vegetation at the drain outlet, but that would be easily
taken care of by a collection container. I've never seen a drain line
that wasn't Tyvek or similar flex tubing or PVC for longer, rigid runs
and either are certainly essentially immune to either.
I'd want to know what, sepecifically, he was "protecting" against.
Either way, to me it's pretty much a "who cares" kinda' thing unless
there were some particular situation.
Bleach is usually Sodium HypoChlorite NaClO. I'm not sure what good, if any,
that would do other then maybe kill living bugs, leaving dead bugs behind
and creating a health hazard if you don't flush it good, or even if you do
flush it good. Vinegar from the jug is so dilute I don't think it would do
much, either, because it doesn't stay in contact with any alkaline material
long enough to do much. If you want to remove mineral deposits, you have to
soak it in vinegar for quite a while. I would just flush the line out with
water under low pressure - garden hose, etc. Anyone else?
All the suggestions so far are speculations that don't work, but get
The only thing that works is mechanical clearing. Most effective is to
flush at the top end with pressure from air or water. Less effective but
usually adequate is a good vacuum at the bottom end.
I personally think bleach is more effective in killng the algea, but we
also have customers who swear by vinegar. I have see lots of houses with
white spots on the carpet in front of the a/c closet, which makes it
obvious they are using bleach, so be careful with the bleach. Also, we
recommend using whichever you choose monthly. Put about a cup in when
you change/check/clean the filter-- you are aleady right there at the
unit, takes only a few more seconds. Neither bleach or vinegar will
guarantee the line will not stop up, nor will it clear a blockage, but
for the few cents either costs, it is a good idea anyway. Larry
I tried household bleach and that did not unclog my drain line.
Compressed air worked somewhat, but when I used a garden hose and
flushed it with hot water it ran freely. I can understand how metal
rust bits or other debris can clog a drain line but I can't see how
algae or bugs can get in there, since the drain in my house is inside
the walls and feeds directly into a drain.
Phisherman, bleach will not usually unclog a line-- just help it to stay
clear. Algae can and will grow in the line, as well as what grows in the
drain pan and then goes into the line. It especially grows in any
horizontal parts of the piping. The possibility of bugs is in the lines
that terminate outside-- not likely to get into one that goes into a
sewer. A lot of the problems we have with drain lines here is with the
3/4 black poly pipe. The insert fittings used with it are about 1/2" ID
and act as a dam which totally stop up to the point that you cannot even
blow them out. You have to take the pipe apart and clean everything. On
the ones where the pipe goes down into the walls all you can do is try
to flush and blow it out as well as possible. Luckily, most of the
systems with black poly are upflow units in single story houses where
the pipe goes into the slab under the unit. I usually take it apart
right at the slab (usually it comes out of the slab at an angle and has
no fittings inside the slab itself) and rod it out with a piece of
romex, and take the rest of it outside and flush it out with the garden
hose as well as rod it out, put it all back together and flush it out
several more times. Usually no more problems for quite a while. Larry
On Sun, 3 Sep 2006 14:29:17 -0500, firstname.lastname@example.org (lp13-30) wrote:
Thanks, one of my A/C drain lines originates in the attic and flows
down three stories, inside walls, and into a down spout. It clogged
up three times this summer. It has been running since I gave it a
hot-water flush. I plan to get a long plumber snake, small enough to
fit into the drain, for the next clog event. I wish the drain pipes
were larger in diameter.
One more thing re: algae and algaecides that I read, I think in an old
post here: someone was able to stand back and see the forest for the
trees and figured out that algae needs sunlight to grow, so there
isn't algae inside of pipes.
Nevermind... I wanted to confirm this, which I believed to be true,
too, so I did a quick google and found that that's not always true.
Turns out a substance called, well, I'll just copy-and-paste it here:
"The explanation focuses on a new word: biofilm. Biofilm is a complex
of living organisms and both organic and inorganic matter that
establishes a presence on the inner surfaces of irrigation lines. The
organisms live comfortably in this environment, and when fertilizers
rich in nutrients are injected into the lines, suddenly life goes from
being comfortable to downright luxurious.
Algae and biofilm are able to form a symbiotic relationship -- what
one needs, the other provides. It's a relationship that keeps feeding
itself, which is a major point in understanding why algae control is
so difficult. Biofilm is able to provide algae with enough nutrients
to substitute for their need of light to create such nutrients. This
allows algae to flourish in irrigation lines, even 5 feet underground
where it's dark."
And here's the url it's from:
It's main focus is a product made of chlorine dioxide which has been
effective as an algaecide.Now, our A/C lines aren't rich in nutrients,
so we shouldn't have near the problem as those with irrigation lines.
But, I guess algae can grow in our pipes, an algaecide therefore would
be effective (if that's the cause of a blockage), but most algaecides
seem to be of limited effectiveness.
Boy, was that a waste of everyone's times! :)
The ends are open to the atmosphere and there are a "virtual plethora"
of airborne molds, bacteria, algae spores, etc., that can get carried
into the lines by the water. Once anything gets a start, it multiplies
and as someone else noted, there are many of these microrganisms that
don't need direct sunlight to flourish.
I've always had pretty good luck w/ the bleach in cleaning out the
condensate line but try to use it frequently enough that it isn't ever
actually fully clogged up first--in that case I can certainly see it
might not be effective. But a preventive maintenance scheduled flush
periodically will, I expect, save you some trouble.
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