What does a TMV do?
A TMV blends hot and cold water to deliver water at a safe, stable temperature, typically around 41°C for showers and 38°C for baths in care settings. If the cold supply fails, it should shut off the hot water so nobody is scalded.
TMV2 or TMV3?
TMV2 valves are certified for domestic use. TMV3 valves meet the NHS specification for healthcare and are often used in care homes and other settings with vulnerable users.
The legionella trade-off
Water downstream of a TMV sits at a temperature where legionella can grow. Keep the pipework after the valve as short as possible, flush regularly and service the valve so strainers and check valves do not clog with scale.
Servicing
TMVs should have an in-service test at least annually, including a temperature check and fail-safe test. In healthcare premises following HTM 04-01, frequencies are set by performance results. See our TMV servicing.
Frequently asked questions
Where are TMVs required?
They are expected where vulnerable people could be scalded, such as care homes, healthcare, schools and nurseries, and in new and refurbished baths in homes under Building Regulations.
Disclaimer: This guide is general information about UK requirements and is not legal advice. Always check the current legislation and guidance for your premises.