Two configurations are available in the integrated variable speed drive E-Circulator line. Series 1000 pumps are suitable for constant temperature, flow and pressure control. Series 2000 pumps add the capability of differential pressure with the use of a transducer to the pump suction and discharge flanges. They can be used in a wide variety of heating systems and the combination of pump, motor and variable speed drive also reduces the space required in the mechanical room or at remote zone locations.