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Trent Tarter
03-12-2010, 03:25 PM
Found this exhaust fan/vent yesterday. It's old, corroded and no longer being used. Fan once vented from basement to exterior. This appears to part of and old radon mitigation system? We don't have much radon around here, no inspectors even offer testing and I have never seen a system installed in any of the homes I have ever inspected. Does anyone have an ideas what this is.

Michael Garrity
03-12-2010, 04:07 PM
Radon mitigation systems are vented to the outside and then rise up above the roof line.The fan is usually located outside at the base of the vent pipe and run 24/7.
What's in your box?

Trent Tarter
03-12-2010, 04:25 PM
A fan is under the metal box, the duct connection in basement was located in a large unfinished room near outside wall.

Michael Garrity
03-12-2010, 04:32 PM
If the pipe is not under the slab then it is not a radon mitigation system.

CHARLIE VAN FLEET
03-12-2010, 04:38 PM
is there a crawl space wood sub floor in house.. if so this could be a thermostat fan under crawl. they usually have intake vent pipe and electric fan, and a thermostat control, usually near sump pit access. check it out.

charlie

Trent Tarter
03-12-2010, 04:44 PM
No crawlspace, home has full basement.

CHARLIE VAN FLEET
03-12-2010, 04:56 PM
trent

all radon exhaust fans should be outside of house--code 1994--do you see flying saucer type fan in basement???--attached to that vent

charlie

Trent Tarter
03-12-2010, 05:07 PM
No just what appears to be a round duct connection. I have come to the conclusion that it's not some type of old radon system.

Bruce Breedlove
03-12-2010, 06:38 PM
It's very doubtful that is some sort of radon mitigation system.


Radon mitigation systems are vented to the outside and then rise up above the roof line.The fan is usually located outside at the base of the vent pipe and run 24/7.


That's right, Michael, but only IF the mitigation system was installed correctly. I see a fair number of new mitigation systems that do not meet the modern EPA protocols. In the last couple of years I have seen relatively recent mitigation systems with the fan located inside the living space, the discharge point below the roof line, the discharge point below windows, systems without instrumentation, and systems that were not labeled.

I still run across old mitigation systems that were installed before EPA updated their protocols (circa 1992). These systems were installed per the previous protocols but can have the fan located inside the living space, the discharge point located at ground level or only a few feet above ground level, no instrumentation and no labeling. Mitigation fans have a useful life of around 10 years so if you see one that is 20 years old it is due for replacement.

I remember one system that was installed almost 20 years earlier and still had the original fan. The fan was making noise but was moving little (if any) air. The discharge point was located at ground level below a bay window that the occupant kept open during warm weather. My radon test indicated high levels of radon. I referred the client to a mitigator with the recommendation that the system be updated to current EPA protocols (which was easier said than done).

Jerry Peck
03-12-2010, 07:04 PM
Jeez, guys, that fan was there to dry out those horse shoes whenever it rained - you can't play horse shoes when the shoes are all wet, you lose control of them. :)

Jack Feldmann
03-12-2010, 08:58 PM
I saw a vent once in a basement and it was for a bomb shelter. I might have posted the photos here, but it would have been several years ago.
Might have been a vent for a workshop, or a photo lab too (in the basement).