Condensate line into floor slab

[J-thetechwizard]

Hello,
Out here in Buffalo, Ny residential hvac companies have been drilling holes in the slab next to the furnace, testing the hole for proper drainage and then running all the furnace and a/c condensates into this hole.

I have accepted this as local code(tradition) and it also makes sense considering this condensate is no different than oridinary ground water under the floor slab, which will eventually seek the sump or drain tile and out.

I never heard yes or no for sure but it is so much easier to do this if possible than running a pump or whatever.

What do you think about this local tradition? is it acceptable to the industry as a whole?

what concerns could there be like radon seepage etc..?

I look forward to your responses.

[Tommy knocker]

Never seen this myself. I guess if there is a decent sand or gravel bed under the slab to allow percolation it's fine. Clogging of drain may be a concern since you couldn't just blow it out. But a union or some other threaded connection in the vertical would fix that. Soo I'd say why not? My condensate drain is the same except for the slab. Dug a 3' hole ran drain 1' down into it filled with gravel dirt back on top 4". No water standing all summer for Mosquitos. Works great.

[Tony3696]

Depending on what's under the slab, it could washout the dirt/sand leaving the concrete unsupported. That could cause cracks, or worse if their is anything load bearing in that area. I have no knowledge of this happening, but is it worth saving an hour and a few bucks to risk it?

[chuckcrj]

I've seen it a few times. Invariably, in my experience, they eventually stop draining.

Just install a pump.

[Nytefog]

I agree it should not be done. I would try to run a gravity drain with clean out tees to a sump or install a heavy duty condensate pump with high quality 3/8 tubing. Also, always leave some slack or a loop of tubing on the pump side in case you need to trim pieces off later on.

I suggest this pump. It cost a bit more but its well worth the extra cost. i have the same one and its about 25 years old now and still running well. PS: i don't take care of it either. lol

http://www.hartell.com/corp/details/0,,CLI1_DIV32_ETI3745,00.html

[hvacvegas]

You guys afraid a little water is going to hurt the dirt?
Imagine how much a sump pump forces out on a heavy rain. Thats only what was so saturated, it weeped into the drain tile/sump crock. Thats a crapload of water. If the ammount of condensate creates vast open pits allowing concrete slabs to crack, imagine what all the water from a rain does!

My house is 50+ years old. Never had a sump (untill I put one in a month ago).
Even after all that water under my house, the house is still here.

If you dump a drain into a sump pump, your doing the exact same thing as dumping it into the slab.

I know, I know. Acidity. Like the acid is going to "eat" the dirt. Come on.

[Nytefog]

You guys afraid a little water is going to hurt the dirt? Imagine how much a sump pump forces out on a heavy rain. Thats only what was so saturated, it weeped into the drain tile/sump crock. Thats a crapload of water. If the ammount of condensate creates vast open pits allowing concrete slabs to crack, imagine what all the water from a rain does!

My house is 50+ years old. Never had a sump (untill I put one in a month ago).
Even after all that water under my house, the house is still here.

If you dump a drain into a sump pump, your doing the exact same thing as dumping it into the slab.

I know, I know. Acidity. Like the acid is going to "eat" the dirt. Come on.


The sump MUST have a pump in it to validate and pass inspection my area. I've come across many issues pertaining to these slab type drains backing up. Even after breaking the material at the bottom of the hole with a long screw driver and i have also added bleach to the hole in attemp to dissolve the dirt. Breaking up the debris on the bottom of the drain may work for a while but tend to backup again securing call-backs which have a great cost and the lose of money you could be aqiuring on another job! Then you have to perform one or two more visits to make up for lost time and money. Do it right the first time and take into account service that must be performed in the future. I make our installers add multiple clean out tees for maintenace and to increase the speed of future repair service calls. I know it increases the price of your bids but if you explain to the customer the added benefits and what is incresing your cost you will beat your competition and demonstrate you knowledge to a customer. I also do the same thing when installing high quality heavy dude condensate pumps and other field supplied materials. As long as you can explain why your price is greater you will have a happy customer that feel your are providing them with a well though out plan by a great group of people that know what they are doing

[pacnw]

Radon escaping

[hvacvegas]

What about radon from a sump crock?

[Nytefog]

What about radon from a sump crock?

They have sealed sumps that have a negative pressure created with a radon exhaust fan. Just have to make sure you have a trap for the condensate drain to prevent radon from escaping. Radon...what BS....

[hkempf]

Well I guess you don't have to worry about freezing but don't you think eventually it would create a void possibly causing the cement to sink

[hvacvegas]

They have sealed sumps that have a negative pressure created with a radon exhaust fan. Just have to make sure you have a trap for the condensate drain to prevent radon from escaping. Radon...what BS....

Yes they do.
Except their not code.

I agree the issues of radon are over estimated.

Just like the issues of water under a slab causing massive erosion. As if natural drainage during a storm doesn't do the same thing.

[carmon]

Bottom line ... poor practice,,,

[canusayinsanity]

I wouldn't do it, you figure your dirt is loose at the top but by adding water eventually it'll cause dirt to compress, sink and act as clay. Then causing water to backup under slap and thru hole. Beside have you ever noticed that globby algae on the bottom of condensate drains, same stuff plugs ptrap that causes service call. So now your introducing that algae at bottom of hole or pit that creates barrier not allowing water to drain.

[Tony3696]

I know, I know. Acidity. Like the acid is going to "eat" the dirt. Come on.

It won't eat the dirt, but it will affect the concrete.

"Concrete is susceptible to acid attack because of its alkaline nature. The components of the cement paste break down during contact with acids. Most pronounced is the dissolution of calcium hydroxide which occurs according to the following reaction:

2 HX + Ca(OH)2 -> CaX2 + 2 H2O
(X is the negative ion of the acid)

The decomposition of the concrete depends on the porosity of the cement paste, on the concentration of the acid, the solubility of the acid calcium salts (CaX2) and on the fluid transport through the concrete. Insoluble calcium salts may precipitate in the voids and can slow down the attack. Acids such as nitric acid, hydrochloric acid and acetic acid are very aggressive as their calcium salts are readily soluble and removed from the attack front. Other acids such as phosphoric acid and humic acid are less harmful as their calcium salt, due to their low solubility, inhibit the attack by blocking the pathways within the concrete such as interconnected cracks, voids and porosity. Sulfuric acid is very damaging to concrete as it combines an acid attack and a sulfate attack." - www.Concrete-experts.com