Boilers

A boiler is a device that heats water to produce either hot water or steam for heating, processing, or power generation. It is distinguished from a storage water heater by its use of pressure, higher temperatures, and its role in supplying systems such as radiators, radiant floors, or industrial processes. Boilers can serve a single building or feed turbines in power plants.

Boilers are typically classified by heat-transfer method and application. Fire-tube boilers have combustion gases passing through tubes surrounded by water, while water-tube boilers have water inside tubes heated by combustion. Residential and commercial installations usually provide hot water for space heating or steam for older heating systems, while industrial boilers may produce high-pressure steam for processes or electricity generation. Fuel sources include natural gas, oil, coal, biomass, or electricity; modern designs often employ condensing technology to recover additional heat from flue gases.

Key components and safety features include the burner, heat exchanger, circulating pump, expansion and feed systems, and controls. Safety devices such as a pressure relief valve, low-water cutoff, and flame safeguard ensure safe operation. Proper venting and combustion air supply are essential to prevent hazardous conditions and carbon monoxide buildup. Regular maintenance is important to detect leaks, remove scale, and verify that safety devices function correctly.

Efficiency and regulation: boiler efficiency is commonly expressed as AFUE for fuel-fired units, with condensing models achieving higher overall efficiency by recovering latent heat. Standards and codes govern design, installation, and inspection; in many regions, installation must meet the ASME Boiler and Pressure Vessel Code and local regulations, typically performed by licensed professionals.