TMV servicing is recommended to take place on an annual basis or twice per year depending on your system. TMV’s must have good access and isolation valves to assist in the servicing, this would be highlighted in your legionella risk assessment.
Thermostatic mixing valves (TMV’s) are there for the safe delivery of temperature controlled water to baths, showers, taps, and other outlets by mixing the hot and cold water. As hot water should be stored at a minimum temperature of 60 °C to kill legionella bacteria this obviously carries the risk of scalding which can be potentially fatal.
Regular TMV servicing is a simple but essential part of your companies’ legionella prevention and water hygiene management plan.
The recommended temperature for a TMV is between 39 and 43 °C. If the valve does not operate as it should between these temperatures then a new valve will be quoted for. After the temperature safety checks are complete the valve is isolated and stripped down to clean, disinfect and descale the strainers, being checked once again before being put back into service.