HVAC Condensation pipe clogged?

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bowserb

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Back when I was researching standby generators, I read a fair amount on an electrician forum, looking to see what generators were most reliable, easiest to service, and so on. An unexpected bit of information I got pertained to ethics, billing practices, and borderline scams. I read enough to be suspicious of electricians generally. I concluded that people who did electrical things as part of something else--like installing a standby generator or swimming pool pumps and such--were the way to do for those kinds of services. They have to be code due to extensive city inspections, and they have to be done right or they'd be back to fix them.

Now reading this thread (plus the cost of replacing a back-flow preventer which froze in the Texas Freeze in February), I'm beginning to wonder about the ethics of professional plumbers. You guys might want to rethink what comments you put on a public forum vs private messaging one another.

I have two A/C units in the attic above the second floor of my house. The condensate--which is considerable down here in southeast Texas humidity--goes into a second floor bathroom sink drain--not unlike the OP's setup. It's occurred to me that according to what I've read, I'm running 10-15 gallons a day of condensate--essentially almost distilled water--into the sanitary sewer system. That seems wrong in this day and time to waste what seems to be otherwise useful water. At the least it seems like this water could be routed to a rain barrel and used to water plants or a garden. In my case, it could be used to replace the water that evaporates from our swimming pool, instead of using city water softened with potassium chloride, to replace evaporation. I'm curious if there is some benefit to having that cool water going into the bathroom sink drain instead of being used otherwise.

And if I wanted to have it rerouted, is that an HVAC job or a plumber job?
 

Twowaxhack

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Back when I was researching standby generators, I read a fair amount on an electrician forum, looking to see what generators were most reliable, easiest to service, and so on. An unexpected bit of information I got pertained to ethics, billing practices, and borderline scams. I read enough to be suspicious of electricians generally. I concluded that people who did electrical things as part of something else--like installing a standby generator or swimming pool pumps and such--were the way to do for those kinds of services. They have to be code due to extensive city inspections, and they have to be done right or they'd be back to fix them.

Now reading this thread (plus the cost of replacing a back-flow preventer which froze in the Texas Freeze in February), I'm beginning to wonder about the ethics of professional plumbers. You guys might want to rethink what comments you put on a public forum vs private messaging one another.

I have two A/C units in the attic above the second floor of my house. The condensate--which is considerable down here in southeast Texas humidity--goes into a second floor bathroom sink drain--not unlike the OP's setup. It's occurred to me that according to what I've read, I'm running 10-15 gallons a day of condensate--essentially almost distilled water--into the sanitary sewer system. That seems wrong in this day and time to waste what seems to be otherwise useful water. At the least it seems like this water could be routed to a rain barrel and used to water plants or a garden. In my case, it could be used to replace the water that evaporates from our swimming pool, instead of using city water softened with potassium chloride, to replace evaporation. I'm curious if there is some benefit to having that cool water going into the bathroom sink drain instead of being used otherwise.

And if I wanted to have it rerouted, is that an HVAC job or a plumber job?
You could have the condensate line ran outside if you like.

HVAC to run the line outside.

HVAC guy might want your plumber to cap the drain line off the existing condensate line uses now.

As a plumber I don’t care what the general public reads on forums, it doesn’t affect my business.
 

BlueSkyHigh

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It's occurred to me that according to what I've read, I'm running 10-15 gallons a day of condensate--essentially almost distilled water--into the sanitary sewer system. That seems wrong in this day and time to waste what seems to be otherwise useful water. At the least it seems like this water could be routed to a rain barrel and used to water plants or a garden.
I capture mine for reuse as much as a boxer would catch "his" to reuse the electrolytes that were lost during exercise and thank you for changing the subject!
 

bowserb

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I capture mine for reuse as much as a boxer would catch "his" to reuse the electrolytes that were lost during exercise and thank you for changing the subject!
OK BlueSky. I get your point even without you adding a [sarc] to it. However, A/C condensate is likely less significant in Northern Virginia than down here in the Gulf South. We use A/C 12 months, and we never "close" our swimming pools.

In fact, on the matter of removing humidity, I'm about to add a dehumidifier to my A/C system, because my A/C can't seem to break the 50% RH barrier. RH in our house is typically low to mid 50's with temp set to 74-78 in summer, depending on time of day. In addition to rerouting A/C condensate to a "rain barrel" on the way to the pool, I plan to have the dehumidifier do the same. When done, according to what I've read, the A/C units plus the dehumidifier should generate 15-20 gallons of 7.0 pH water a day, saving me adding city water at 8.0 pH and then periodically adding muriatic acid to get back to 7.5.

Rerouting the condensate will also send that cool water in summer out to a pool that often hits 90+ degrees, and I'll be doing a little to save water treatment for our little city. Even if it saved only 10 gallons a day, that's 300 gallons a month. If the other nine pool owners in my little 50-home subdivision did the same, we'd be saving 3,000-4,000 gallons a month.

Good luck with your boxing career. Congrats on your new governor.
 

BlueSkyHigh

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Sorry for the (sarc) but I couldn't resist. Roger that on your humidity which is much more than we've experienced here. My RH is a high of 42 in the worst case and drops off to the high teens when we've got the heat running and that's with a whole home humidifier that may or may not be sized properly for the house.

We are looking forward to our new governor but, as always, actions speak louder than words and I've taken a wait and see approach to managing my expectations.
 

Mitchell-DIY-Guy

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It’s a great “green” idea:
If you search there are also a number of videos about using condensate water…

When I bought my house here the condensate drains went outside to one side of the house just dumping on the grass. For the most part that is how the builders do things here, although as an inspector I have seen some attic furnace/air conditioning units drain directly into the second floor drain for the washing machine on new construction.

In the crawlspace of my home I rerouted this to an air gap and into the homes main sewer/drain system. The problem for me was that one side of the home that took all the condensate water was always mucky and never dried out. The clay soil here could not absorb all that water and this area never got any sun. The right thing to do would be to collect this somehow but in a more controlled manner and use this free water. The collection and disbursement system would have to be reliable enough and not that costly as well.
Our water rate here is $1.77 per hundred cubic feet, or 748g.
 

BlueSkyHigh

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Ours is $7.30 per thousand gallons plus the meter, taxes and other charges. We are also charged for that same water going down the drain to be recycled regardless if that water was sewerage or irrigation.
 

Mitchell-DIY-Guy

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Yes that’s a bit more costly than we have here in the Charlotte area. We also have the ability to have a separate meter for irrigation, which I do have, for which they give you a slightly different rate but more importantly they do not charge you for any sewage. so worst case it’s about half.
 

SHEPLMBR

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It’s a great “green” idea:
If you search there are also a number of videos about using condensate water…

When I bought my house here the condensate drains went outside to one side of the house just dumping on the grass. For the most part that is how the builders do things here, although as an inspector I have seen some attic furnace/air conditioning units drain directly into the second floor drain for the washing machine on new construction.

In the crawlspace of my home I rerouted this to an air gap and into the homes main sewer/drain system. The problem for me was that one side of the home that took all the condensate water was always mucky and never dried out. The clay soil here could not absorb all that water and this area never got any sun. The right thing to do would be to collect this somehow but in a more controlled manner and use this free water. The collection and disbursement system would have to be reliable enough and not that costly as well.
Our water rate here is $1.77 per hundred cubic feet, or 748g.
Condensate water is highly corrosive as it is pure water with no minerals, etc.
Why is condensate water acidic?


Waste water is drained into your sewer system while waste gasses like carbon monoxide are piped outside of your house. Although the waste water, or condensate, created by combustion is technically clean, it has a PH between 2.9 and 4, which makes it acidic.
 

bowserb

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Condensate water is highly corrosive as it is pure water with no minerals, etc.
Why is condensate water acidic?
Waste water is drained into your sewer system while waste gasses like carbon monoxide are piped outside of your house. Although the waste water, or condensate, created by combustion is technically clean, it has a PH between 2.9 and 4, which makes it acidic.
I can see waste water with pollution from toilets, showers, etc. being undesirable and hazardous. A/C condensate--straight from the evaporator--should be pretty clean (assuming filters are maintained), and pure water has a pH of 7.0. That's more acidic than city water but not a problem for irrigation--at least not here where our soil needs sulfur added for flowers and even St. Augustine grass. And especially for a pool where ever-rising pH is a problem, addition of 7.0 pH water would save adding even more chemicals (muriatic acid) every week to keep the pH in the mid 7's.

Thanks Mitchell DIY Guy for the link.

BTW, wine is typically in the 3-4 pH range. Orange juice is around 3.5. Cow's milk is 6.4-6.8.
 
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bowserb

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OK. I'm not a plumbing, A/C, or heating expert. I see that air gets sucked into a return, goes through a 4" pleated filter, continues on through the furnace fan, furnace heat exchanger, and A/C evaporator coil, then on out via registers. In the case of our downstairs unit, there is also a fresh air intake ahead of the filter, but I don't think that's relevant here--other than being a huge source of humid air most of the time. What I don't understand is how the gas burner in the furnace can produce condensation in the airflow. And the condensate discussed here is from the cold evaporator coil, both in the OP and my hijacking of the thread (apologies...still related, though.) BTW, here is another article I've found on use of A/C condensate:
 

Twowaxhack

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A gas burner doesn’t produce condensate in the air flow of an HVAC systemIt creates it in the burn chamber.
Same for a gas water heater.

Burning gas creates water vapor......

There are different types of condensate, depends on the source.
 

bowserb

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A gas burner doesn’t produce condensate in the air flow of an HVAC systemIt creates it in the burn chamber.
Same for a gas water heater.

Burning gas creates water vapor......

There are different types of condensate, depends on the source.
OK, that's what I thought. Since we're talking about condensate from the evaporator coil, caused by condensing humidity from the airflow, what happens in the furnace combustion flame doesn't impact this, right?
 

Twowaxhack

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OK, that's what I thought. Since we're talking about condensate from the evaporator coil, caused by condensing humidity from the airflow, what happens in the furnace combustion flame doesn't impact this, right?
Correct, but I wouldn’t drink it unless I was really thirsty 🤓
 

bowserb

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Correct, but I wouldn’t drink it unless I was really thirsty 🤓
I wouldn't drink it. In fact the article I linked talked about for swimming pool or domestic water that it should be biocide treated, which also in the article is reference to UV, ozone and chlorine treatment. In the case of my pool, my system has all three of those, so I'm comfortable with that water for swimming. Since treatment is not necessary for irrigation use, that is easy. I've found a local supplier of rain barrels for collecting condensate and with a hose fitting near the bottom.
 

Twowaxhack

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It’s ok irrigation but it not quality water for irrigation. You could mix some fertilizer in it if you used it on container plants.
 

bowserb

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It’s ok irrigation but it not quality water for irrigation. You could mix some fertilizer in it if you used it on container plants.
Agreed...you could add a little Miracle Grow and be all set. Many flowering plants prefer lower pH than our 8 pH tap water. I don't know what the pH coming out of the pipe is, but it certainly starts out as pure water, which would be 7 pH. So a mix of tap and condensate would probably be good for plants in pots. As to swimming pools, it is perfect, since pool owners constantly deal with evaporation and rising pH.
 

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