Looking to confirm my suspicions. Does this look to be a passive Radon system? There was no fan in the attic? The larger pipe is 4" PVC routed through the attic and exiting the roof. The cover to the sump pump and pipe exiting appears to be sealed. But if you look close there is a gap between the cover and concrete floor. I can’t think of any other reason to have the sump vented.
Where does the pipe terminate??
This appears to be a sewage lift pump (but it could be adapted for other purposes. There appears to be a backflow/check valve on the smaller pipe…this would be the waste carrying pipe into a main waste pipe or stack. The sump needs to be vented…the 3-4" pipe is a little larger than needed at the interior for venting but does the job.
Are there any plumbing fixtures in the basement? What is the height of the building drain to the exterior…does it exit the house above the basement floor level?
The small pipe with check valve is the sump discharge pipe that exits the side of the home. The larger pipe run up through the subfloor next to the out side wall and up through the attic and exhaust above the roof like stack vent. There are no plumbing fixtures in the basement or other waste pipes connected to it.
The home is a two story colonial. The bathrooms and kitchen are on the opposite side of the of the home.
I agree with Brian. This is a sewage lift pump, this can be confirmed by flushing the lowest toilet 3 times and listening to the impeller kick in to remove waste if it does not then maybe it is a control for Radon that looks like a sewage lift basin.
Maybe they tried to kill two birds with one stone at the sump pump installation with thoughts of being able to add a radon exhaust fan later. Not that bad an idea (1) as the sump tank is an air tight unit and (2) if holed drain pipes extend from the tank well out under the slab. Next question …will the AHJ allow this if the radon sub-slab system is mandatory as it is in new construction in my area?
Looks like a conventional sump pit with the addition of a sealed cover and rough-in for a Radon mitigation fan if needed.
These are becoming more common around my area.
If a Radon test shows elevated Radon a fan and manometer gets added.
Still needs to be sealed tight . And if it is for radon it should be identified
Michael, I agree with you. The home is hooked up to public sewer. In this area iMichigan there is plenty of Radon. The home was built in 2003 so it may be a system prep for radon or a system intended for removal. I will suggest testing
Sump basin if I am not mistaken.
This could be below the french drain and the system being enclosed needs to circulate the flow of water because it gets large amounts of water . Per gallon an hour rate.
If I am not mistaken , if it was a radon escape duct it would have an electric fan and be running 24 / 7.
1: Is the basement below the water line . Lake , high water table near the surface grading ?
2: is there a washer dryer above the unit and with in 20 feet of the basin?
3 is there a new toilet install within that area? I have seen a lot of bad ideas.
I have seen and repaired may cooked up drainage systems.