When the radon fan quits, the system quits
Fans run around the clock for years and eventually wear out. Repairs end with a gauge that reads true and a retest that proves it.
The system that came with the house
Sioux Falls has been installing radon systems long enough that the early ones are now old machines. Homes mitigated during the 2000s and the transaction-testing wave of the 2010s are carrying fans that have run every hour since. A fan that has spun for a decade owes you nothing.
Plenty of owners never chose their system at all. It came with the house: a white pipe by the furnace, a gauge nobody explained, a hum from the garage attic. Then one day the hum stops, or the gauge reads level, and there’s no manual.
That’s this page. Diagnosis, fan replacement, and getting the gauge to say something true again. If you just want to check the system yourself first, is my radon system working? walks through it in a few minutes.
Sound familiar?
-
The hum stopped
A fan you used to hear by the garage or outside the basement wall has gone silent.
-
The gauge fluid sits level
Equal fluid in the u-tube usually means the system has lost suction.
-
A new rattle or grind
Bearings wearing out often announce themselves before the fan dies outright.
-
You inherited a mystery system
The pipe came with the house and nobody explained what any of it does.
-
Gurgling in the pipe
Water sounds after a cold snap can mean condensation is pooling where it shouldn't.
Reading the gauge yourself
The little tube of colored fluid on the pipe is a manometer, and it’s simpler than it looks. It measures one thing: whether the pipe has suction.
When the fan is pulling, it holds a slight vacuum in the pipe, and that vacuum drags one side of the fluid up and pushes the other down. Uneven fluid is good news. The system is working.
When the two sides sit level with each other, the pipe has no suction. The fan may have died, lost power at the breaker or switch, or been unplugged during some other project and never plugged back in. Level fluid doesn’t say which. It just says the system isn’t pulling, and the house is back to whatever its untreated radon level was.
Check it the way you’d glance at a sump pump: on your way past, a few times a year, and after any electrical work. Mark the normal fluid position with a pen line and you’ll spot a change in half a second.
What a webpage can’t do is diagnose your particular system. A gauge can mislead. A blocked pipe can hold vacuum with no airflow, and a marginal fan can pull weakly while the basement creeps back up. The system-check guide covers what the gauge can and can’t tell you. When the reading looks wrong, the next step is eyes on the system.
What a repair visit covers
A repair call typically starts at the fan, since the fan is usually the answer. It gets checked for power, then for life. Dead or dying fans get replaced with a unit matched to the system’s pipe size and suction needs, because sizing matters more than brand, and the right choice depends on what the original system was designed to do.
While the system is open, the rest gets a once-over. Pipe joints and the slab seal loosen with age. Condensation traps and low spots show up after our winters, since warm soil air meets a cold pipe and drips back down. The gauge gets checked against reality rather than refilled and trusted.
Then the part that makes it a finished job instead of a parts swap: a radon test. A spinning fan is not the goal — a low number is. After any repair, a retest is how you confirm the system is doing its job again. The testing guide explains the options, or you can have a test scheduled along with the repair.
Gauge looks wrong or the fan's gone quiet? Have it looked at
Frequently Asked Questions
How long do radon fans usually last?
Most run on the order of a decade, in industry experience — some quit sooner, some push well past it. They run 24 hours a day, so the mileage adds up quietly. The gauge is usually how an owner finds out one has stopped.
Can I replace the fan myself?
A handy owner sometimes can, but there are real considerations — the fan is wired in, it has to match the pipe and the system's suction needs, and a mismatched swap can leave the house reading high with a gauge that looks fine. If you do it yourself, retest afterward either way.
Why is the system louder than it used to be?
Usually worn bearings in the fan, occasionally vibration against a mount or water pooled in a low spot of pipe. Louder is the system asking for attention — it rarely gets quieter on its own.
What does the u-tube gauge actually tell me?
One thing only — whether the fan is pulling. Uneven fluid means suction, level fluid means none. It says nothing about the radon level itself, which is what retesting is for.