
Steam Trap Inspection: How Failed Traps Burn Money
15–30% of steam traps are typically faulty. Ultrasound identifies blow-through, closed and healthy traps in seconds without shutting the line.

The invisible cost line
A steam trap should pass condensate and hold steam. When it fails open (blow-through), live steam escapes 24/7. Large sites have hundreds or thousands of traps; industry data says 15–30% are faulty at any time — up to half without a survey programme. One medium blow-through trap can waste steam worth hundreds of thousands of tenge per year.
Steam is invisible and the trap body stays hot whether healthy or failed — you will not see the problem until fuel bills rise or header pressure drops.
Three trap states
- Healthy — cyclic condensate discharge, steam retained.
- Blow-through (failed open) — continuous steam loss, overloaded condensate return.
- Failed closed — no condensate flow; water hammer, corrosion, lost heat transfer.
Both failure modes hurt — one hits the budget, the other hits equipment and process quality.
Why ultrasound is the best field test
Trap condition is revealed by internal flow sound, which is loud in the ultrasonic band. A contact instrument such as the SDT340 on the trap body shows within seconds:
- healthy — intermittent cyclic signal;
- blow-through — continuous high-level hiss without pauses;
- closed — silence despite a hot upstream line.
Unlike infrared temperature alone, ultrasound reads flow character, not just heat — so it separates blow-through from a healthy hot trap.
TrapChecker mode
TrapChecker on SDT devices guides the operator: enter trap type and steam pressure, apply the sensor — the instrument returns OK / blow-through / closed and estimates losses. Results tie to route tags for prioritised replacement reports.
Building a survey programme
- Inventory all traps with type, size and pressure.
- Group routes in the instrument.
- Baseline survey — flag failures and quantify losses.
- Repair highest-pressure blow-through traps first.
- Repeat 1–4 times per year depending on criticality.
Payback is often within the first survey cycle.
Related tasks with the same tool
The same ultrasonic device covers compressed-air leaks, bearing lubrication, partial discharge and early pump cavitation.
Conclusion
Failed steam traps are among the largest hidden losses on any steam system. Ultrasound diagnoses them in seconds without a shutdown; TrapChecker automates the verdict and loss estimate. KEG TRK supplies SDT instruments and helps Kazakh plants build trap survey programmes — contact us for a savings estimate.
Read also
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What to Test Steam Traps With: Comparing SDT to the Competition (UE Systems, TLV, Fluke, Spirax Sarco)
Comparing steam trap diagnostic methods and instruments: temperature, acoustic cameras, online monitors, and ultrasound. Why the SDT340 with TrapChecker is more accurate than the competition.
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How to Survey Steam Traps with SDT Ultrasound: Step-by-Step Method
Practical steam trap survey method from SDT: upstream/downstream readings, temperature for failed closed, blow-through signatures, how to read the cycle. Field photos with SDT340.
