Use Extra Care When Plugging Boiler Tubes

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Use Extra Care When Plugging Boiler Tubes

Incomplete Boiler Repairs Can Drain Profits

Plugging rather than replacing tubes is common practice when repairing commercial and industrial boilers. But a recent claim paid by Hartford Steam Boiler points out the importance of making sure all water is drained between the plugs.

Trapped Water

Extensive scale build-up in the insured’s boiler had caused several tubes to leak. A repair company found a probe could not be pushed through some the tubes and recommended plugging the offending tubes. This was done at the upper and lower drums. However, water was trapped between the plugs and the scale build-up. The scale must have been completely solid, because when the boiler was fired, the plugged tubes ruptured. The steam release damaged the rear wall of the boiler.

What Was the Lesson Learned?

When tubes are plugged instead of replaced, precautions must be taken to assure no water remains trapped between the plugs or between the plugs and internal deposits. One method would be to drill one or more holes in the plugged tubes to vent any trapped water. Normally, plugged tubes are leaking, and the leak provides the necessary vent. In this case it did not. Somewhere between one or both plugs was an obstruction creating a volume that was not vented.
Before tubes are plugged, a probe should be used to determine if there are any obstructions. If the tube is obstructed, several drilled holes may be required to assure no water remains in trapped volumes. Ultimately, the plugged tubes should be replaced as part of the normal maintenance on your boiler.
Disclaimer statement:

All recommendations are general guidelines and are not intended to be exhaustive or complete, nor are they designed to replace information or instructions from the manufacturer of your equipment. Contact your equipment service representative or manufacturer with specific questions.

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