A thermostatic mixing valve, or TMV, is an instrument that blends hot and cold water to produce a constant and safe water temperature for baths and showers. TMVs are therefore the primary method of reducing the risk of scalding from hot water. They are particularly common in care homes and hospitals where scalding presents a greater danger, but building regulations now stipulate that all new-build homes in the UK must have devices fitted to baths to limit the temperature of the water to 48°C.

Children and elderly people are particularly vulnerable to scalding. In 2012, an 88 year-old resident died at a care home in North Wales after being lowered into a scalding hot bath that did not have a TMV fitted. The company that ran the home was fined £5,000 and went into liquidation soon after the incident. Cases like this demonstrate the importance of having TMVs attached to baths, particularly in high-risk environments like care homes.

How do we fit and maintain a TMV?

It's crucial that TMVs are fitted and maintained properly. For a start, the valve should be fitted as close to the outlets as possible and ideally should not feed more than a couple of outlets. We have seen some sites that have tried to save money by fitting a TMV to the calorifier outlet pipework so that it blends the whole water supply, but this creates a high risk of bacteria growing in the pipework as the hot water should be going through the pipework at no lower than 50°C in order to help combat bacteria growth.

TMVs should be inspected at least once a year to ensure that they are functioning correctly and that there is no dirt that could lead to bacteria growth. Our engineers will check that your TMVs are operating as they should and that they are producing the recommended temperature range. We will also clean, descale and disinfect any strainers or filters associated with the TMV. We will help to keep your water supply clean, safe and compliant.

To find out more about our TMV service, head to the page on our website.