Controlled water temperatures


Thermostatic Mixing Valves (TMVs) ensure water temperature is controlled for showers, baths etc. by mixing hot and cold water. The health and safety implications of a faulty TMV are severe so regular servicing is very important.

Hot water must be stored at a higher temperature than that at which it is dispensed to kill the Legionella bacteria, so it is crucial that regular TMV servicing takes place to prevent potential scalding incidents if the valve is not operating correctly. Servicing also includes cleaning, descaling and disinfection to extend the lifespan of the TMV and to maximise its operational capacity.

Lubron can service your TMVs as part of a Legionella prevention programme and will provide documentary evidence of the findings to support your compliance records.

“TMV” you might be wondering what this stands for…..The Mars Volta? True market value?…yes but not what we cover here at Lubron

TMV Thermostatic Mixing Valve

Here at Lubron we bring compliance and sense to these very important but over used valves

TMVs are valves that use a temperature sensitive element and blend hot and cold water to produce water at a temperature that safeguards against the risk of scalding, typically between 38°C and 46°C depending on outlet use. The blended water downstream of TMVs may provide an environment in which legionella can multiply, thus increasing the risks of exposure.

The use and fitting of TMVs should be informed by a comparative assessment of scalding risk versus the risk of infection from Legionella. Where a risk assessment identifies the risk of scalding is insignificant, TMVs are not required. The most serious risk of scalding is where there is whole body immersion, such as with baths and showers, particularly for the very young and elderly, and TMVs should be fitted at these outlets. Where a risk assessment identifies a significant scalding risk is present, eg where there are very young, very elderly, infirm or significantly mentally or physically disabled people or those with sensory loss, fitting TMVs at appropriate outlets, such as hand washbasins and sinks is required.

TMV servicing & maintenance… What does it involve?

Our inhouse TMV servicing and maintenance solutions are delivered by our experienced, infield water treatment and engineering experts and include the following:


Examine each TMV to identify if the correct specification valve is fitted, good accessibility and if isolation valves are fitted.


Measure and record the mixed water temperature to ensure it is between 39°C and 43°C.


Perform an in-service TMV failsafe shut-off test, isolating the cold water supply.


Isolate each TMV and clean, descale and disinfect valve components and fine mesh strainers.

Expert TMV servicing, maintenance & failsafe testing

Contact Water Treatment Services today to learn how our expert TMV servicing and failsafe testing solutions can help you maintain water quality standards, safe water temperatures and meet regulatory standards required or your organisation.


What does TMV stand for?

TMV (Thermostatic Mixing Valve) are valves that use a temperature sensitive element and blend hot and cold water to produce water at a temperature that safeguards against the risk of scalding

What types of TMV’s are available?

There are mainly two types of TMVs.  These are the difference between TMV2 and TMV3 valves:

TMV2 valve is the most common valve used in domestic settings.
It must be regularly maintained to meet the national and international standards are met, valves designed to work with water pressure that falls within 0.1 -1.0 bar (BS EN 1287) and 0.5 bar – 5.0 bar (BS EN 1111)

Unlike TMV2s, TMV3 is mostly used in a hospital or healthcare environment. You will rarely find a TMV2 in care homes or hospitals. This is because TMV2 does not meet NHS requirements. TMV3 is also designed to work with water pressure that falls within 0.2 bar – 1.0 bar (Low Pressure D08) and 1.0 – 5.0 bar (High Pressure D08).

What temperature should a TMV valve be set to?

Typically between 38°C and 46°C depending on outlet use.
In healthcare scenarios HTM 04 has specific temperature setting guidance

What servicing is require on a TMV?

TMVs are fitted to minimise scald risk, they require regular maintenance to ensure hot water is reaching the outlet at a suitable temperature.

The maintenance usually includes:
Fail-Safe Testing
Full Annual Service
Lubron can test, failsafe, service, calibrate & replace all types of industry approved TMVs

Can I install a TMV valve that feeds many outlets to reduce install and maintenance cost?

No – guidance recommends valves that are incorporated into the tap or installed as close to the outlet as possible usually within 2 meters. This is to reduce the Legionella growth after the valve. As valves are set to 38-46°C this is an optimum growth temperature therefore the balance of scalding versus bacteria growth need to be carefully assessed.