Is my radon system working?
Radon systems fail quietly. There is no alarm, no error code, and no symptom in the house — which is why the manometer exists and why a two-year retest habit matters more than it seems.
These are the checks a homeowner can safely make. Everything past them belongs to a certified contractor, and the tool says so rather than encouraging you to keep going.
Work it through
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The gauge on the pipe with coloured fluid.
A working unit is a continuous low hum.
Grinding, rattling, or a rising whine that was not there before.
The dedicated circuit serving the fan.
A measurement in living space, not a gauge reading.
Basement finished, HVAC replaced, drain tile or sump added, air sealing done.
What this indicates
Reading your inputs…
Why this says what it says
The full working, shown rather than summarised. Nothing below is hidden behind a toggle, because reasoning that takes a click to reach has not really been shown.
What you told us, and what each answer did
| Your answer | Value | What it influences |
|---|---|---|
| Manometer reading | Columns are at different heights | The gauge on the pipe with coloured fluid. |
| Fan is audible | Yes | A working unit is a continuous low hum. |
| Noise has changed recently | No | Grinding, rattling, or a rising whine that was not there before. |
| Breaker is on | Yes | The dedicated circuit serving the fan. |
| Tested in the last two years | No | A measurement in living space, not a gauge reading. |
| House changed since the system went in | No | Basement finished, HVAC replaced, drain tile or sump added, air sealing done. |
What we took on trust
- Your answers about manometer reading are taken as described. Where a description is approximate the output is approximate in the same way.
- The yes/no conditions (fan is audible, noise has changed recently, breaker is on, tested in the last two years, house changed since the system went in) are accepted exactly as you set them. Nobody has confirmed any of them, and the output assumes each is as stated.
What is still unknown
- Why a suction field falls short in your specific house. That requires instruments a homeowner does not have.
- How long your fan has left. Manufacturer warranty terms differ by model and duty, and a general service life figure would be invented.
Why this stops short of a decision
This runs entirely on what you typed. Nobody has been to your house, nobody has seen the device or the laboratory record, and the choice between courses of action follows from diagnostics performed on the building. What you have here is a reading of what you reported, which is a different thing from a decision and a good basis for making one.
What would change this
- Field data on time-to-detection of silent fan failure, split by whether a manometer, an alarm, or a resident monitor was present, would establish which monitoring approach actually shortens the exposure window.
- A survey of post-mitigation systems by age would establish real component failure rates, which currently exist only as manufacturer warranty terms.
- Correcting any answer above. Change an input and the output changes, which is the honest behaviour of something working from a description.
The procedure, in order
- Read the manometer
Find the gauge on the riser. Offset fluid columns mean the fan is developing suction; level columns mean it is not.
- Listen for the fan
A working unit is a continuous low hum. Silence from a fan that used to be audible is the simplest diagnosis available.
- Check the breaker
Confirm the dedicated circuit is on. This costs nothing and explains a meaningful share of dead systems.
- Check what has changed
A finished basement, an HVAC replacement, new drain tile, or air sealing can outrun a design that was previously adequate.
- Test the air
Run a short-term test on the lowest lived-in level under closed-building conditions. The gauge reports pressure; only a test reports concentration.
- Call a certified contractor if indicated
Bring the result, its date, the placement, the conditions, and the manometer reading. Ask for a sub-slab pressure field diagnostic rather than a guess.
The logic, in full
These are the rules the tool applies — not a summary of them. The interactive panel above evaluates exactly this list, and a build check fails if the two ever diverge. A decision tool whose reasoning you cannot inspect is a black box, and a black box is not authority.
| When | Then |
|---|---|
| Manometer columns are level | The system is not developing suction. Check the breaker first because it costs nothing, then call the installer. A level manometer is never something to ignore. |
| Manometer level and breaker is off | Reset the breaker and re-check the gauge. If it trips again, stop and call a contractor — a repeatedly tripping circuit is an electrical fault, not a nuisance. |
| Fan is not audible and the manometer is level | The fan has most likely failed. Replacement is a swap on the existing pipe; retest after it is done. |
| Noise has changed to grinding or rattling | Bearing wear is the classic pre-failure symptom. Book service and check the manometer at the same time — if it has also drifted, the fan is already losing performance. |
| Manometer offset and fan audible but no test in two years | The system is pulling air, which is not the same as the room being below the action level. Run a short-term test under closed-building conditions. |
| House changed since installation | Retest regardless of the gauge. A finished basement, an HVAC swap, or new drain tile can outrun a design that was correct when it was installed. |
| Manometer cannot be found | Ask the installer where it is, or have a contractor inspect. A system without a working indicator cannot be checked at all, which is a defect in itself. |
| Everything checks out | Keep the monthly gauge glance and the two-year retest. Those two habits catch essentially every failure mode in this list. |
What this tool cannot do
- This tool covers checks that are safe for a homeowner. It never asks you to open a fan housing, touch wiring, or work on a roof discharge — those are hazards and, in states with radon certification, credentialed activities.
- A gauge reading is not a radon measurement. Only a test reports the concentration in the room.
- It cannot diagnose why a suction field falls short. That requires sub-slab pressure measurement by a contractor with instruments.
Related
- Should I retest? — Time since the last test, plus what has changed in the house — the two things that decide it.
- Compare two quotes — Review both bids on the eight lines that explain almost every price gap.
- System not working — Diagnose in order: the test, then the fan, then the design. Most "failed" systems fail at one of the first two.
- Fan noise and vibration — Most radon noise is a mounting problem, not a fan problem — and the fixes are usually inexpensive.
- Retest failed — An elevated verification result is unfinished scope, not a lost cause — and who pays depends on what the contract promised.
- What to expect after installation — Verification, noise, energy, maintenance, and retest intervals.
- Mitigation System Component and Service-Life Dataset — What each part does, how it fails, and whether you would notice.
- Radon Mitigation Cost Driver Index — The variables that move a quote, their direction, and their relative magnitude — no invented dollar figures.
- All tools — every calculator and decision tool.
Confidence and limits of this page
Every decision resource on this platform states its own boundaries. This is not a disclaimer — it is the part of this tool you should read before relying on it.
- What we knowClaims on this page we stand behind, each traceable to an approved source or to observable structure.
- Radon fans fail without a symptom in the house, which is why a manometer is fitted and why offset fluid columns are the primary indicator of suction.
- Fan, roof, and electrical work are hazards and, in states that credential radon work, credentialed activities. This tool never asks a homeowner to perform any of them.
- Sub-slab pressure field extension measured at test holes is the professional diagnostic that determines suction-point count and fan sizing.
- What we do not knowQuestions you may reasonably have that this page does not answer.
- Why a suction field falls short in your specific house. That requires instruments a homeowner does not have.
- How long your fan has left. Manufacturer warranty terms differ by model and duty, and a general service life figure would be invented.
- What research would settle itWhat it would actually take to answer the above — naming it is the difference between honesty and hedging.
- Field data on time-to-detection of silent fan failure, split by whether a manometer, an alarm, or a resident monitor was present, would establish which monitoring approach actually shortens the exposure window.
- A survey of post-mitigation systems by age would establish real component failure rates, which currently exist only as manufacturer warranty terms.
- What we do not claimClaims you might expect to find here and will not, with the reason.
- We do not claim a passing gauge check means your house is below the action level. Only a measurement in living space reports that.
- We do not claim a service life in years for any component, because that depends on model, duty, and environment.
- What we cannot independently verifyFacts this page relies on that we could not confirm ourselves.
- What your manometer read at commissioning, which is the only baseline a current reading can be compared against.
Sources
- U.S. EPA — Radon
- U.S. EPA — Consumer’s Guide to Radon Reduction
System not performing?
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