Dead Radon Fan? - American Radon Mitigation

Dead Radon Fan?

Dead radon fan? Check this before calling your mitigation company.

We were recently called out to a home to replace a dead radon fan because the customer noticed that their U-Tube gauge was reading zero. Both fluid levels were equal to zero, indicating a problem with the radon system. It ended up being something really simple, though, so make sure you read to the end to find out what to check before you call your radon mitigation contractor.


In this article, we are going to talk about your two options for when it is time to replace your radon fan. 

You can do a simple fan swap. Take the dead radon fan out, and replace it with the equivalent fan. Or you can bring everything up to the current code and do what’s called system optimization. We will show you some of the things that we personally would recommend if this were our house, and in this case, we’ve recommended to the customer.


We would first recommend sealing gaps and cracks because the radon system works by creating suction underneath the home.


This home has some cracks that could be sealed. You can see where the contractor sealed this crack here.

Sealed Crack


This home has 6 mil poly that is against the poured foundation wall.

6mil poly

Then you can see the crack along the wall, a pretty significant gap. So, we know they are losing conditioned air that is being drawn from the house. This is air they’re paying to heat and cool going down these cracks and openings.

Floor to wall gap

Here is where the water line comes up through the floor, and you can also see a gap there. So we would definitely recommend sealing these things to make the system more energy efficient.

Water Line Gap

Plumbing Block Out

If we go out of the mechanical room, there is a big one that should also be sealed.

Showers with a fiberglass tub like this have a plumbing block out underneath. That is where the plumber has room to hook up their drain.

Fiberglass Tub

That is where the plumbing comes through the floor for the bathtub drain, and you can see the rock there, and the concrete is not poured up tight to that. We would also recommend foaming that to seal it up and make it more energy efficient.

Plumbing block out

Pressure Field Extension (PFE)

Another thing we always talk about is that the key to lowering your radon levels is creating a system that has or creates a vacuum or suction under the entire floor. We do that through a process called pressure field extension.

So what’s involved in this?

When measuring pressure field extension, we pull up the corner of the carpet (if the home has carpet), then drill a couple of half-inch holes through the floor and hook our gauge, called a micromanometer, up to them. From there, we can take our readings with the micromanometer, which allows us to measure the amount of suction the radon fan creates. We can dial everything in once we know these numbers so the fan is not oversized or undersized. We want to balance radon reduction with energy efficiency.

When it comes to system optimization, there are new EC radon fans with a potentiometer, which means there’s a dial in there, so we can dial that fan into exactly the settings we need.

In this house, the radon suction point is in the mechanical room. So the areas that are going to be hardest to reach are their son’s bedroom in the opposite corner. Another bedroom is on the opposite side of the basement, near the bathroom. And finally, probably the hardest area to reach is between them in the living room area. We would recommend test holes in these places.

When we are finished, we fill the holes and stretch the carpet back into place. We know this scares a lot of people, but you would never notice that the test holes were there.

Pipe Insulation and Pitch

Out in the garage, we’ve got the radon pipe where it comes out of the mechanical room and runs up into the garage attic. You’ll see the pipe has a red firestop collar up by the ceiling. We are glad to see that safety measure. We would like to see insulation on that pipe, though.

Firestop Collar

The pipe comes up in the garage attic and runs along the trusses in the attic. We would also like to see insulation on this pipe since it’s now required by code. That was another one of our recommendations to the homeowner.

Radon pipe in attic

Another thing to point out is you will see our level, the pipe pitches back to the fan here, so we’re going to get a little bit of water that’s trapped in the pipe that can’t run back to the sump pit like it’s supposed to. We would recommend fixing the pitch on that as well to allow the water to drain properly.

Radon pipe pitch

The Simple Fix

Let’s see what the simple fix for this radon fan was up in the attic.

We came out to replace the radon fan. So, we went up to the attic right away to see what kind of fan we had to swap it out with, and we saw this red light on the outlet was on. We hit the reset button, and BOOM! Our fan was back up and running.

Quick tip if you are experiencing a radon fan failure or you think you are, check the GFCI. We aren’t sure what caused this one to trip. Maybe it’s an electrical issue or something with the fan, but we’re going to monitor it for now.

This homeowner will do another radon test to ensure their radon levels are indeed low. If the radon levels come back higher than they’re comfortable with, they’ll have us come back and do the system optimization and sealing we recommended.

GFCI Outlet


In conclusion, you’ve got a few options to think about when it comes to replacing your dead radon fan. You can simply swap it out for an equivalent model, bring everything up to current radon standards, or do the system optimization to ensure that your radon system is both energy efficient and effective to keep you and your family safe.

If you are interested in fan replacement or system optimization, give us a call at 612-474-1004 or contact us.