How to Read a Radon Manometer (And Know If Your System’s Working)
Radon mitigation systems work by pulling radon-laden air from beneath your home and venting it outside through a series of PVC pipes and a radon fan.
But how can you tell if your system is doing its job? Enter the manometer, a simple gauge that gives you a quick visual check on whether your system is creating the suction needed to keep radon out. In this guide, we’ll cover what a manometer is, how to read it, and when to call in a professional.
What Is a Manometer?
A manometer is a pressure-measuring device consisting of a clear, U-shaped tube partially filled with a colored liquid. In radon mitigation systems, the manometer can be found on the pipe near the suction point and offers a quick visual indicator of whether the mitigation fan is operating and maintaining proper suction.
One side of the tube connects to the vent pipe, which is under suction from the fan. The other side is open to the surrounding air. Your radon fan’s suction pulls the liquid in the tube upward on one side and downward on the other, creating a height difference between the two columns of liquid. This difference, measured in inches of water column (inWC), represents the strength of the vacuum in the system.
What Does a Manometer Measure?
It’s important to note that the manometer only measures pressure — it does not measure radon levels. However, regularly testing your radon levels is another great way to check that your mitigation system still works properly. A radon monitoring device makes it easy to watch your levels over time and catch any problems early on.
How to Read the Manometer on Your Radon System
Reading a manometer is simple. For the most part, you just need to check the two liquid columns. If one side is higher than the other, you’re usually good to go. Uneven liquid levels mean your radon fan is working. If both sides are even, there’s no pressure difference, which indicates a problem with the fan or system.
However, you also want to monitor the inWC measurement to catch any abnormalities or changes. Look at the side of the monometer tube connected to the pipe/fan. This side should be higher than the other. Where it falls on the markings along the tube (in inWC) will tell you the current pressure.
What Should a Radon Manometer Read?
Most systems run between 0.5 and 1.5 inWC, but older homes without gravel under the slab might read much higher, between 3.0 and 4.0 inWC. What matters most, though, is the baseline reading recorded when your mitigation system was installed. This number may be written on a sticker or marked on the pipe itself. Use this reading as a baseline to compare against when checking your manometer.
When to Bring in an Expert
Your manometer can help you gut-check the status of your mitigation system, and you’ll want to call a company like The Radon Guys if you notice anything off with your readings. Watch for:
Equal Liquid Levels: If the liquid on both sides of the manometer is at the same height, it could mean the fan is off, unplugged, failed, or there’s a break in the system.
Sudden Drop in Reading: If your manometer reading is significantly lower than the initial reading, it can indicate a partial blockage, a fan that’s losing power, or a leak in the pipe.
Sharp Increase in Reading: If your reading is suddenly higher than the baseline, it could indicate a partial blockage that’s causing the fan to work harder than it should.
Liquid Loss or Damage: If the colored liquid has evaporated, leaked out, or is no longer visible, the manometer can’t provide a reading. This may also point to a system issue.
In addition to checking your manometer, you also want to keep an eye on your radon level itself. If your ongoing radon test or monitor shows elevated radon despite regular manometer readings, your system may not be venting effectively.
Is Your Radon Manometer Reading Off? Call The Radon Guys
Learning to read your radon manometer is key to ensuring your mitigation system is working correctly. Whether you're seeing unusual readings or just want peace of mind, The Radon Guys are ready to respond if anything’s off. Reach out today to schedule a quick system review.
