As we enter the heart of winter and turn our attention toward cold weather conditions where freezing water can wreak havoc on commercial and residential property, the threat of catastrophic failure to boilers looms large (as seen in Figure 1).

Although failsafes against significant boiler failures do exist and continue to improve, they remain far from perfect.

One particularly susceptible failsafe is a boiler’s low water cutoff (LWCO). An LWCO is designed to alert the boiler that it does not contain sufficient water to “fire,” and prevents the boiler’s burners from igniting until a safe water level has been restored.

Installation of low water cutoffs

Because these types of failures can lead to injury or death, most state and municipality codes require the installation of low water cutoffs for both residential and commercial boiler applications.

LWCOs are found in one of two designs: Electronic-probe (a more recent technological introduction) and mechanical-float.