A thermostatic mixing valve (TMV) is a device that blends hot and cold water to regulate the temperature of your water supply and ensure against the risk of scalding.
TMV’s are necessary because in certain facilities hot water must be stored at a temperature of at least 60 degrees celsius to prevent harmful bacteria like Legionnaires’ disease from spreading. However, it only takes a second for water above 60 degrees to scald. To prevent this, a TMV mixes cold and hot water before it reaches the point of supply to deliver water that is clean and at a safe temperature to use.