Most Common Types of Boilers

Last Updated: May 1, 2019

Most common types of boilers

Boilers come in a variety of shapes and sizes but ultimately serve the same purpose. All boilers hold heat and circulate water for various applications including heating or powering buildings. Depending on the size and style, boilers can burn various types of fuel and operate at different pressures and levels of capacity. Regardless of the type of boiler it's important to maintain efficiency through the use of chemicals. Click here to see all the types of chemicals USCS offers. 

Fire Tube Boilers

Fire tube boilers are the most common type of boiler. The burning fuel passes through a series of tubes composed of a mild steel material, located within the water tank. As the fuel is pumped through the tubes, heat is transferred to the water, ultimately producing steam.

Most modern boilers run on natural gas. Pressure ratings depend on the boiler make. The boilers are typically sized by horsepower - the more horsepower, the more steam (pounds per hour) that the boiler can produce.

Water Tube Boilers

As the name indicates, water tube boilers are designed so that the water is contained within the tubes, while the burning fuel remains on the outside. Why would a facility use a water tube boiler over a fire tube? Application is the primary factor in determining whether a water tube boiler is necessary. That’s because water tube boilers can handle much higher pressure (1000s of psi), while fire tubes generally aren’t designed to be used over 250 psi. Additionally, water tube boilers are able to recover from an increase in load much faster than fire tubes, making it the preferred choice for a facility with inconsistent demands.

Steam and Hot Water Boilers

The main difference between a steam and hot water boiler is the amount of energy used to operate the boiler. Due to the amount of energy required to convert water to steam, a hot water boiler uses as much as 25% less energy than a steam boiler. Steam boilers, however, are more efficient when it comes to heat transfer as the steam provides a much larger output of heat than water. Hot water boilers are typically used in industrial heating systems for smaller buildings or heating needs and require a closed loop chemical to prevent corrosion and microbiological growth.