Radon U-Tube Manometer

A u-tube manometer is a required part of a radon mitigation system. Here we will cover what it is, how to install one and how to read it.

What is a U-Tube Manometer?

A u-tube manometer contains a u shaped tube which is half full of liquid. When correctly installed, the pressure created by your radon fan will cause one side of liquid in the u-tube to be higher than the other.

A manometer does not read radon levels. It's purpose is to be able to quickly reference if your radon fan is working. If your fan has stopped working the two sides of the u-tube will show the same amount of liquid. So with just a quick glace you'll be able to reassure yourself if all is working correctly.

Also, the level of pressure shown on your manometer will help you determine if you are using the correct radon fan. Depending on the reading shown you may need higher- or lower-suction fan.

For more on radon fan selection see this page.

How to install a U-Tube Manometer

Installing a manometer on your radon mitigation system is pretty simple.

STEP ONE: Find an easy to access spot below the radon fan to install the manometer. Generally, people choose to install the manometer in the basement or garage. The important thing is that it be in a place where you can easily read it.

Continue reading how to install your u-tube manometer below or watch this quick video...

STEP TWO: Once you've found where you want to install the manometer screw it to the pipe using the enclosed screws. Make sure it is vertically level.

STEP THREE: Slide the tube up or down until the oil reads 0.

STEP FOUR: Drill another hole just above the manometer to insert tube into the pipe. Make sure to drill downward into the pipe. This prevents condensation from backing up into the manometer.

STEP FIVE: After inserting the tube add a bit of caulk where the tube enters the PVC pipe and where it enters the manometer to prevent it from slipping.

Reading Your Manometer

When the radon fan is on and sucking air through the radon mitigation system, the oil level in the manometer will change as you can see in the photo.

Depending on the radon fan you are using and the soil conditions you are working with the level will be different. Higher readings mean less air flow.

Each radon fan comes with a chart showing the max pressure level for that fan. You want your manometer to read somewhere close to but not above that pressure level. It can be a bit lower than the max level "WC"; however, if the level shown is higher or quite a bit lower, you may need a different fan. The same enclosed chart shows other fans for you to compare. See the above video for some examples.