Series PWW is designed with two isolated water circuits: one on the supply side and one on the process side. The demand side includes a coolant reservoir and a circulating pump. The process side includes an electronically actuated ball valve for modulating coolant flow rate to maintain the desired process or equipment temperature. Options include supply-side filters for dirty water and high pressure pumps for long process-side pipe runs. Additional features of the water-to-water heat exchanger line include a temperature controller with remote start/stop input, alarm output relay and models with two standard capacities (24,000 or 48,000 W).