Steam heat

Steam heating

A steam heating system takes advantage of the high latent heat which is given off when steam condenses to liquid. In a steam heating system, each room is equipped with a radiator which is connected to a source of low-pressure steam (a boiler). Steam entering the radiator condenses and gives up its latent heat, returning to liquid. The radiator in turn heats the air of the room and provides some direct radiant heat. The condensate water returns to the boiler either by gravity or with the assistance of a pump. Some systems use only a single pipe for combined steam and condensate return. Since trapped air prevents proper circulation, such systems have vent valves to allow air to be purged. In domestic and small commercial buildings, the steam is generated at relatively low gauge pressure, less than 15 psi (100 kPa).