How To Properly Read a Radon Mitigation System’s Gauge

How To Properly Read a Radon Mitigation System’s Gauge

A functioning radon mitigation system features a gauge called a manometer, also called a U-tube due to its shape. When you know how to read your radon mitigation system’s gauge properly, you can tell at a glance if the system is working or if you need to call for professional repairs. Familiarize yourself with the U-tube to understand how it works.

What Is a Manometer?

A basic active radon mitigation system consists of a fan and a vent pipe, with a small gauge on the piping near the point of installation. That U-shaped gauge is called a manometer, and it’s filled with colored fluid that indicates the amount of suction the system is producing.

The fluid levels in your manometer do not directly indicate how much radon is in your home. They simply tell you whether or not the system is switched on and pulling radon out of the suction pit in your basement.

Reading the U-Tube

When your radon mitigation fan is venting radon out of your home as intended, the fluid levels in your manometer will be different on each side of the U shape. The side with higher fluid levels indicates the amount of suction occurring inside the vent pipe. The higher the number next to the fluid reading, the more powerful that suction is.

However, this doesn’t necessarily mean you should aim for maximum suction at all times in your radon mitigation system. All homes have different levels of airflow and require varying amounts of suction to reduce radon levels.

Readings To Look Out For

An ideal readout on a functioning manometer is between 0.5 inches and 1.75 inches. If the reading on the higher end of the U is in this range, and if the U is unevenly filled on each side, your mitigation system is working properly.

The following readings indicate potential problems with your radon mitigation system:

  • Zero: A reading of zero means that your system is not hooked up to power.
  • Equal lines: If both sides of the U have equal fluid levels, power and suction are insufficient.
  • Max pressure: Maximum readings may indicate too much suction in the vent pipe.

Knowing how to read a radon mitigation system’s gauge properly is an essential skill to develop as a safety-conscious homeowner. Check your manometer regularly to ensure that your radon fan system continues to adequately vent dangerous gas out of your home.


Learn how to properly install a manometer with this tutorial.