Boilers are fuel-burning appliances that produce either hot water or steam that gets circulated through piping for heating or process uses. Boiler systems are major financial investments, yet the methods for protecting these investments vary widely. Proper maintenance and operation of boilers systems is important with regard to efficiency and reliability. Without this attention, boilers can be very dangerous.
Fire-tube boilers rely on hot gases circulating through the boiler inside tubes that are submerged in water. These gases usually make several passes through these tubes, thereby transferring their heat through the tube walls causing the water to boil on the other side. Fire-tube boilers are generally available in the range 20 through 800 boiler horsepower (bhp) and in pressures up to 150 psi.
In general, the critical components are those whose failure will directly affect the reliability of the boiler. The critical components can be prioritized by the impact they have on safety, reliability.
The most important rule for the safe operation of boilers is to maintain the proper water-level at all times, and as constant a level as conditions will permit. If water is not visible in the water glass.