P Trap Drying Problems - Furnace Condensate

[Tony_Pro]

Furnace Condensate

• Tony_Pro
• Dec 28, 2018

Need some advice please. See attached picture.

There is a P trap off my main drain line that is feed only by the furnace concentrate drain. This trap either keeps drying out or is being siphoned by the main drain line. It is producing a sewage smell when the trap is not full. We have a septic tank if that matters.

What can I do to ensure the P trap does not dry out? Or, should I connect it to the venting system? So it vents out of our roof, instead if in the basement.

Also, interestingly, the smell becomes stronger when we have fires in our fireplace. Maybe the flue is heating air in our attic and in therefore heating our vent system?

 

[SHEPLMBR]

your furnace condensate should NOT be tied into your sewer.

 

[Tony_Pro]

your furnace condensate should NOT be tied into your sewer.

Interesting. Where should it drain then?

 

[SHEPLMBR]

floor drain or sump pump. That right there that you have is not legal here where I am. It is for the reasons you are experiencing.

 

[Tony_Pro]

floor drain or sump pump. That right there that you have is not legal here where I am. It is for the reasons you are experiencing.

Unfortunately I don't have a floor drain or sump. I could run the condensate line into the wash basin. Or maybe directly into the ejector pump sump? Are either of those acceptable. See pic.

 

[SHEPLMBR]

Maybe directly into that sink. That ejecter pump needs to remain sealed.

 

[Tony_Pro]

That's what I'll do then. Thanks for the help!

 

[Diehard]

floor drain or sump pump. That right there that you have is not legal here where I am. It is for the reasons you are experiencing.

Are you saying that the code does not allow an indirect drain from furnace condensate into a trapped standpipe?
Why would that be, other than the fact that the trap may be subject to drying up in some cases.
Of course the sink is fine for that purpose. Not sure why the condensate would have its own dedicated standpipe. But couldn't find where it would not be legal in the IPC.

EDIT: Do you think that's the reason he's losing the trap seal and getting the smell? If the trap seal is being loss due to what appears to be questionable proper venting, it may take the seal from that other trap we see dumping into that line. ???

 

[phishfood]

That trap is rather close to the ejector pump tie in. Seems I recall a minimum separation distance that needs to be there. I will look it up.

Edit to add: I only have an old (2010) IPC book here in the house. But in 712.3.5, it is requiring a minimum of 10 feet from the sump connection point to any fixture drain.

I can envision that being a problem in this case, possibly causing air pressure variations for that trap, and possibly sucking some of the water out of it.

 

[Diehard]

2018 IPC ON LINE...It's still reads the same. It's also suppose to connect to the top of the drainage pipe. Not sure if that's a factor. ???

https://codes.iccsafe.org/content/IPC2018?site_type=public