TL;DR
A failed-open trap is blowing live steam continuously. Confirm with an ultrasonic tester, then isolate and replace the trap internals (the Armstrong 800 has a replaceable bucket module). Leaving a blown trap in service wastes significant energy.
What you might see
- continuous high-velocity discharge at trap outlet
- trap outlet piping hot with no condensate discharge cycle
- ultrasonic reading showing high-frequency continuous signal
- increased steam consumption with no process change
Likely causes
Worn or eroded valve seat allowing live steam to pass continuously
Eroded orifice from flashing condensate or water hammer enlarging the seat opening
Broken or collapsed bucket mechanism no longer closing the valve against steam pressure
Wire-drawing erosion on the valve seat from an initially leaking seat that progresses to full failure
Required tools
- Ultrasonic steam trap tester
- IR thermometer
- LOTO kit and isolation valves
- Heat-resistant gloves and face shield
- Armstrong 800 repair kit (correct size and pressure class)
- Torque wrench for trap cover
Safety first
- Steam burns are instantaneous and severe. Isolate, drain, and depressurize the trap completely before opening the cover.
- Wear heat-resistant gloves and face shield when working on any steam trap.
- Verify the isolation valve fully closes before opening the trap. A passing isolation valve still allows lethal steam pressure into the trap body.
Procedure
- 1
Test the trap with an ultrasonic detector or IR thermometer at both the inlet and outlet. A failed-open trap shows the same high temperature at inlet and outlet and a high-frequency continuous ultrasonic signal with no modulation.[1]
- 2
Isolate the trap by closing the upstream isolation valve. Confirm the trap outlet cools within 2-3 minutes after isolation. If the outlet stays hot, confirm which valve is leaking.
Warning: Never open trap internals on a trap that is not isolated. Steam at operating pressure will cause severe scalding burns. - 3
Drain the condensate from the trap body by opening the downstream drain or loosening the trap cover slowly.
Warning: Wear heat-resistant gloves and face shield. Even after isolation, residual pressure and hot condensate remain in the trap body. - 4
Open the trap cover and remove the bucket and valve assembly.[1]
- 5
Inspect the valve seat and orifice for erosion or pitting. A groove visible to the eye around the seating surface confirms seat damage.
- 6
Replace the complete internals with the Armstrong 800 repair kit for the correct trap size and pressure class. The kit includes a new bucket, valve, and seat assembly.[1]
- 7
Reassemble the trap. Verify the cover bolts are torqued to the Armstrong specification.
- 8
Open the isolation valve and re-test with the ultrasonic detector. Confirm a normal cyclic discharge pattern.
Sources
Armstrong 800 Series Inverted Bucket Steam Trap Installation and Maintenance, Armstrong International
Armstrong International 800 Series Steam Trap Installation and Maintenance Instructions, inverted bucket inspection and repair (general)
View source
More guides for Armstrong International 800 Series
How to diagnose a cold Armstrong 800 steam trap
A cold trap means no steam is reaching it. Check the upstream isolation valve first, then the inlet strainer. A cold trap with upstream steam and no isolation valve closed is a failed-closed trap or a plugged strainer.
How to diagnose continuous discharge on an Armstrong 800 steam trap
An Armstrong 800 inverted-bucket trap at full condensate load will discharge nearly continuously. Distinguish normal operation from a fault by checking with an ultrasonic tester: continuous high-frequency noise means steam loss; intermittent modulated noise at high rate is normal condensate discharge.
How to fix waterlogging from a failed-closed Armstrong 800 steam trap
A failed-closed trap does not discharge condensate, causing waterlogging upstream. Test with an IR thermometer: the trap inlet will be cold. Isolate, clear the strainer, and replace the trap internals if the strainer is clean.
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