Freezing conditions can cause metal to expand and contract with changing temperatures, sometimes resulting in burst pipes and water damage. This may occur in boiler system components such as the pipes, terminal units, or valves.

Voltage fluctuations can impact electrical components, including those found in boiler systems. These include the thermostats that signal the boiler to power on or off, the electric low water cutoff that ensures there is enough water in a boiler, or the electronic ignition if there is one. Other components impacted by surge can include aquastats that maintain water temperature, circulating pumps, and electronic zone control valves.

Wear and tear is the most common cause of loss for boilers. It may occur because of thermal fatigue, the stress to metals from repeated heating and cooling; a puffback, when there is a buildup of unburned fuel that ignites and pushes out of the burner section and releasing excess smoke and soot; or a malfunctioning low water cutoff from mineral deposits, which could cause a boiler to keep running without sufficient water or to stop running with a false message of a low water supply.

Prolonged water exposure could cause losses to electrical components, the burner, or the combustion or heat chamber. Systems with underfloor tubing may also sustain pipe leaks that cause water damage under finished flooring.