Thermostatic steam traps reduce start-up times and improve overall efficiency. Balanced Pressure Thermostatic Traps use a special bellows diaphragm. The diaphragm is designed to open in response to pressure and temperature to discharge air and condensate, and to close against passage of steam. The temperature at which a Thermostatic Trap opens is variable, but is 10 to 30 deg F below saturated steam temperature for the existing pressure. This type of trap is small, simple in construction, size and weight, and has adequate capacity for various applications, especially in low-pressure heating systems.