Sterling condensate and boiler feed pumps & pump repair parts from State Supply. Select from simplex (1 pump and motor) and duplex (2 pumps and motors) configurations. Boiler feed pump and tank combinations are normally controlled by the water level control unit on the boiler. When the boiler needs more water it sends a signal to the boiler feed pump. Condensate pumps are controlled by the float switch on the pump’s receiver tank. It does not care what the boiler wants. Because of this, most condensate pumps are simply transfer pumps - sending condensate to the boiler feed tank. Tanks available in both cast iron - for harsh water conditions - and steel tanks - for normal or treated water conditions. A wide range of tank receiver sizes and pump discharge pressures available.