# Floor Drain for AC Condensate Discharge



## ColoradoGirl (Jun 18, 2013)

I have a condensate discharge pipe from evaporator coils for my AC that runs to a floor drain (has a cover with small holes in it) in basement. Most of the water will go down the drain, but some will pool on top of the drain cover and get the surrounding floor wet. I have a structural wood floor in basement and would like to eliminate this problem. Can I cut more holes in drain cover so that the pipe (PVC pipe with an elbow on the end) can stick directly into the hole and eliminate the pooling water?   Or are the better drain covers (one that is concave in middle) to eliminate this problem.


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## nealtw (Jun 18, 2013)

Welcome to the site: I don't know if there are rules about it but I have seen where a hole is drilled for an elbow to connect the drain.


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## ColoradoGirl (Jun 18, 2013)

The elbow on the discharge pipe (3/4"?) from AC just sits on top of the floor drain cover right now, most of the water goes down the drain but some will run off of cover onto surrounding wood floor (structural wood basement floor instead of concrete in my neighborhood).  Want to eliminate water running off of cover.


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## nealtw (Jun 18, 2013)

I would think you could drill a hole in the cover so you could stick the elbow right into it.


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## JoeD (Jun 18, 2013)

The AC drain should definitely turn down into the drain not just run over the top of it. Either cut a hole in the existing drain or make a new cover with a hole in it and add an elbow.


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## CallMeVilla (Jun 18, 2013)

I like your thinking Girl  ...  Condensate lines acn be REALLY gross (see pic below).  Here is what you can do:

1.  Get a PVC elbow to fit your drain line where it reaches the drain cover.
2.  Fit it to the line and with a Sharpie mark the diameter where it hits the drain cover.  If it sits above the cover, you can get a short section of drain PVC to fit into it.  Mark that diameter on the drain cover.  Basic principle:  You want the new cover hole to be tight so nothing can get into the drain ....  or crawl out of it either.  EWW
3.  Drill holes and cut the drain cover to fit the new drain pipe extension.  If you want to get really crazy, you could use some kitchen/bath silicone to seal it  ...  but that is probably not necessary.
4.  Install the extension in the cover, slide it onto your drain pipe, screw down the cover.

You LIKE??

Celebrate in a manner you enjoy!


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## kok328 (Jun 18, 2013)

I believe code requires an air gap between the drain and the pipe thus precluding inserting the pipe into the drain hole.


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## nealtw (Jun 18, 2013)

kok328 said:


> I believe code requires an air gap between the drain and the pipe thus precluding inserting the pipe into the drain hole.


 
I was afaid of that, do you what the thinking is for that


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## JoeD (Jun 19, 2013)

Sticking an elbow into the drain would still be an air gap unless you seal the drain cover around the pipe.


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## kok328 (Jun 19, 2013)

All air gaps have to do with backflow prevention.
If the drain pipe clogs then the elbow will be below the water level of the drain.
2" clearance is typical for an air gap.


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## bud16415 (Jun 19, 2013)

It&#8217;s hard to envision a condensate line back flowing. But code is code I guess. 

If it were mine I would just poke a bigger hole in the cover or take the cover off.


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## nealtw (Jun 19, 2013)

I can't see the back flow thing but, drill the hole and put a T in it, leave the top of the T open. Not sure how you get it 2" above when the pipe is always laying on the floor.


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## mudmixer (Jun 19, 2013)

If you have a basement or utility area with other appliances (water heaters, wash machines, dehumidifiers, etc. the drain should already have a trap, but needs a slotted open cover to allow surface water in.

You could buy a cheap plastic drain cover and cut a hole large enough to to accept and open "L" turned downward.

Dick


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## JoeD (Jun 19, 2013)

> 2" clearance is typical for an air gap.


So the pipe laying on the floor beside the drain is no good either then. It needs to be raised 2" up off the floor?


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## nealtw (Jun 19, 2013)

JoeD said:


> So the pipe laying on the floor beside the drain is no good either then. It needs to be raised 2" up off the floor?


 
I am a non beleiver, I would want to know the language in the code, out here we see these things with an elbow down, we also see them connected to the floor drain below the level of the floor and I have seen one hooked to the overflow in the back of a bathtub. This has to do with air venting behind water, so I suspect if the rest of the screen is open to the air, the trap will not syphin empty problem solved. There has to be more to the rule than just a distance above.:


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## nealtw (Jun 19, 2013)

So after a little digging, 
AS I understand it, the AC unit can or will draw air thru this line back to the unit and if the sewer backs up could pull sewer into the unit (I guess everything out here is against code)
So cut the pipe in the vertical drop and add a funnel and leave an air gap for the water to fall 2" into the funnel and elbow the pipe into the drain at the floor.
Then you will be the only person that is to code.


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## ollie24018 (Jun 27, 2013)

Just add a p-trap to the condensate line where it comes out of the condenser.


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## nealtw (Jun 27, 2013)

ollie24018 said:


> Just add a p-trap to the condensate line where it comes out of the condenser.


 
Care to explain the need for a trap here.


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## ollie24018 (Jun 27, 2013)

The P-trap with water in the trap prevents pulling the "sewer gas" from the drain when the blower is running.  Just stick the pipe into the drain grate.


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## nealtw (Jun 27, 2013)

Most of this discussion was around the air gap and I under stand the trap if you were going straight into a sewer pipe but for the same reason that line would have to be vented. Now that I understand the reason for the gap I see no reason for a trap too.
Are you suggesting a trap instead of a gap, you still need a clean air vent or an air gap so water dosn't get sucked into the AC


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## ollie24018 (Jun 27, 2013)

The trap stops flue gases from entering the drain pipe, and allows free flow, or stopping "water slugging". That's also why you have to trap a/c condensate with the evap coil on the negative side of the blower.

The trap is on the negative side of the blower. if the trap was not in place, the blower would suck air up through the drain line not allowing the condensate to flow out. thus causing a flooding problem.

Just following what my HVAC man told me.  Makes sense.

I hope this helps.

Sounds as though many ideas.  Mine works and have had no issues for 30 years.


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## nealtw (Jun 27, 2013)

But the code says you need a 2" gap between the pipe and the vessel so the fan dosn't suck sewer into the AC and this particular set up the pipe just sat above the drain and spilled water on the floor.  So it looks like they want it both ways. If a trap works don't worry about the sewer backing up, so what's the gap for? I'm just trying to understand. I guess we need your HVAC to explain it. And welcome to the site:beer:


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## ollie24018 (Jun 28, 2013)

The condensate pipe just goes down into the drain opening. When a sewer backup occurs it will spill out onto your floor.  It will not be sucked up into the equipment because you a P-trap with water in the elbow. Water prevents any suction.
Mine has been working this way for 25 years and no issues.


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## nealtw (Jul 5, 2013)

If it won't suck water out of the trap why would it suck it out of the sewer.


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