The Sterling 5000 J Series high capacity boiler feed pumps are designed to collect return condensate and return it to the boiler. Water levels are maintained by a mechanical make-up water valve with a heavy-duty float switch. The boiler feed pump is controlled by a boiler controller that senses the boiler water level and sends a signal to the pump for water. These Sterling boiler feed units have narrow diameter 3/16" heavy steel receiver tank with a standard gauge glass assembly and feature automatic venting. The centrifugal pump is bronze-fitted with a "SterlSeal" ceramic seal. The 503300JF has a 1-1/2" connection and a 1-1/2 HP, 3450 RPM, 208-230/460v three phase motor. The 503300JF is a simplex unit, with a 210 gallon tank, capable of pumping 45 gallons per minute at 30 psi and 300 BHP.