Our Boiler Feedwater Pumps Just Do Not Perform Like Before

This article discusses the performance problems associated with process water pumps. It highlights that at a boiler steam load in the 25% to 40% range, an automatic recirculation (ARC) valve is simply not accurate enough to detect a minimum pressure differential change of possibly 1–2 psig when the boiler drum level control valve closes for short-duration process demand changes. Converting the ARC valve to an electronic controller does not work reliably either. The amperage change is difficult to discern at low feedwater flow rates. Failure of the valve to open is a recipe for pump cavitation and becoming “steam bound.” If the boiler trips on “low water,” plant production can be affected immediately. For larger boilers with high-capacity, high-horsepower feed pumps, the ARC valve often becomes an energy conservation (cost) issue.