Since 1995, David Bohn has served as president of Preferred Utilities Manufacturing Corporation in Danbury, near Redding, CT. David Bohn draws on a 30-year history with the Redding, CT-area company, during which time he has gained an in-depth knowledge of boilers and the risk of dry-firing.
A boiler depends on balanced temperature and pressure levels to operate correctly. If a boiler ever becomes empty of water, pressure drops to zero and the boiler works harder to restore pressure. The lack of water leads the boiler to overheat and can permanently damage the metal mechanism, assuming an emergency feedwater pump does not first introduce cold water to the hot metal and cause an explosion.
Testing and monitoring are key to the prevention of dry-firing. Contemporary controller systems have mechanisms for monitoring stack temperature, so that excess heat would prompt a shutoff. Similar shutoff procedures may occur with automated low water testing.
Plant owners can also help to prevent dry-firing by installing redundant feedwater pumps, which engage in the case of pump failure and can help the mechanism avoid drying. Similarly, a feedwater header-pressure transmitter can emit an alarm and engage a second pump if pressure drops, thus reducing the chance of a dry boiler.