Which of the following is a common cause of boiler failure?

Low water conditions or water carryover is frequently a common cause of boiler failure. When there isn't enough water in the boiler, it can lead to overheating of the boiler components, which can ultimately cause the metal to weaken or fail. In extreme situations, this can even result in a boiler explosion. Conversely, water carryover can also create problems as it may lead to operational issues like water hammer, damage to the steam piping, and a reduction in steam quality.

Excessive fuel supply could lead to fuel wastage or inefficient combustion rather than outright boiler failure. High steam pressure concerns typically relate to safety issues and regulatory limits but would not directly cause failure if properly managed. Lastly, while periodic maintenance checks are essential for the longevity and safe operation of the boiler, performing them too frequently is generally not an issue; rather, it reflects a commitment to maintaining equipment reliability.