Thermostatic Mixing Valve Maintenance

TMV maintenance is an essential part of water safety in the workplace. TMVs (Thermostatic Mixing Valves or Taps) are used in many applications such as handwashing, bathing, showering, and for any other hot water supplies in which a risk of scalding has been identified. If TMVs are not serviced and maintained to the manufacturers, specification, then this can result in poor operation and could result in the users of the water outlet being scalded. TMVs can also become an area for potential Legionella Proliferation. Through experience, it has been noted that a TMV fed outlet is far more likely to result in a positive. Legionella sample than a directly supplied hot water outlet. This is due to the lower temperature they operate. The mixed supply pipe from the valve to the outlet should be kept to an absolute minimum and point of use mixing would be the preferred method. Therefore, TMVs should only be installed where it is an absolute necessity. Regular use and flushing of mixed outlets and regular servicing and maintenance should help prevent the colonisation of mixed outlets and the supply pipes.