The VT200 Radiator Thermostat senses the air temperature around it and can limit room temperature by regulating individual radiator output in wet central heating systems. Radiator thermostats are particularly useful in taking advantage of uncontrolled heat gains (e.g. solar gain or an open fire in a living room). According to Building Regulations Part L1 radiator thermostats should be fitted “on all radiators except in rooms with a room thermostat” to satisfy either Minimum or Best Practice installations. The valve can be mounted vertically or horizontally at either end of a radiator. To work correctly, the VT200 should be installed to a two pipe heating system and also have a free flow of air around the head to sense temperature.