Steam heating systems are usually found in older homes, but are still sometimes installed today. A steam boiler heats water to boiling temperature creating super heated steam. The steam from the boiling water rises through the distribution system of piping and is delivered to either radiators or baseboard convectors. As the steam passes through the convection system and exchanges the heat into the air, it cools and returns to the boiler. A steam system operates at low pressure and has unique features for its operation such as low water cut off switches, automatic feed valves, glass gauges and other controls. Steam systems must be installed well or knocking from condensation in pipes, excess water use, or incomplete delivery of the steam may occur.