We became involved with this project because the existing domestic hot water boilers were constantly failing due to excessive corrosion. We discovered the cold city water make-up line was piped to the entering side of the boilers, thus causing flue gas condensing problems. This pipe was relocated to the discharge pipe of the boilers, before the hot water entered the storage tank. Through the use of our ultrasonic flow meter and data logging equipment, we determined that the existing boiler control system was slow in responding during periods of high usage. We recommended a new control system, which utilized a flow meter in the city water pipe to speed up the control loop when the flow reached a set point.