Thermostatic Mixing Valves – TMV Valves
Thermostatic mixing valves or TMV valve is a mechanical device installed on hot and cold water supply pipework upstream of wash hand basins, sinks, baths and shower units. The TMV valve mixes the hot water usually at 60°c and the cold water down to a safe desired tap outlet temperatures typically between 39°c and 43°c
The installer or maintenance engineer sets the outlet temperature using the thermal cartridge within the valve body which is blended using the wax capsule and piston. Most TMV valves have a safety shut down in the event of the loss of the cold water supply to prevent the outlet temperature becoming too hot and scalding the user
Safety
Its very important to have TMV valves fitted where vulnerable users of the hot water basins, sinks, baths and showers. People with a reduced ability or sense may not perceive risk which may result in scalds. Young children and older people have thinner skin and can scald much easier.
Below is a the exposure times for partial thickness burns from hot water
