TMV Servicing

TMV Servicing | TMV Maintenance | TMV Fail Safe Testing

What is a Thermostatic Mixing Valve?


A thermostatic mixing valve (TMV) is a device that ensures water temperature is at a safe and comfortable water temperature level preventing people from burning themselves. Hot and cold water is blended as it passes through the valve on its way to the tap, ensuring it is at a safe temperature by the time it reaches the water outlet.

Hot water sources such as hot water cylinders should be kept at a temperature of 60oC in order to prevent bacteria such as legionella from breeding. As such, these high temperatures may scald the skin. Therefore it is necessary to blend the hot and cold water temperature to ensure safe use, particularly where vulnerable persons are present. This is important when it comes to accessible toilets and service user areas as some users are not able to move away from the water quickly enough to prevent burning. Others may have conditions where they cannot physically feel any temperature changes.

TMV Servicing is required as children and the elder are particularly at risk from scalding from hot water with statistics showing that nearly 600 people suffered serious scalding injuries in the UK each year. And 75% of those scalded were children under five years of age. This is why Thermostatic Mixing Valve or TMV servicing is essential.


Scalding Risk in Temperatures

What temperature does scalding start for vulnerable people?

When it comes to scalding, the HSE states that – “There is a risk of scalding where the water temperature at the outlet is above 44°C. In certain facilities with ‘at risk’ patients this is especially so where there is whole body immersion in baths and showers of vulnerable patients, including the very young, elderly people, and people with disabilities or those with sensory loss who may not recognise high temperatures and respond quickly.” HSG 274 – p.2163

What temperature is scalding for most people?

“For most people, the scalding risk is minimal where water is delivered up to 50°C at hand wash basins and using hot water signs may be considered sufficient, where a TMV is not fitted. However, where vulnerable people are identified and have access to baths or showers and the scalding risk is considered significant, TMV Type 3 (TMV3) are required.” HSG 274 – p.2.164

What Type of TMV and Where?


“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 and TMV Servicing is 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 burning 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 (thermostatic mixing valves) at appropriate outlets, such as hand wash basins and sinks, is required.” HSG 274 – p.275


TMV Servicing in Health Care Buildings


“Where a scalding risk is considered significant (eg where users are very young, very elderly, infirm or significantly mentally or physically disabled or those with sensory loss) then type 3 TMVs that are pre-set and fail-safe should be provided (but are required at healthcare premises) and should be checked regularly to ensure they are fail-safe if the cold water supply pressure is interrupted.” HSG 274 – infobox 2.3: Thermostatic mixing valves: TMV Servicing & Failsafe Testing


TMV Servicing for Healthy Users


“Where a scalding risk is assessed as low (e.g. where healthy users immerse their entire body), type 2 TMVs that can be overridden by the users are required by building regulations.” HSG 274 – infobox 2.3: Thermostatic mixing valves & TMV Servicing


TMV basic
TMV Delabie

What temperatures should a TMV be?


Set to 38-43°C

Showers and hair-wash facilities

Set to 41°C

Unassisted baths

Set to 41°C

Baths for assisted bathing

Set to 46°C


Set to 38°C

Note – bath fill hot water temperature of more than 44°C should only be considered in exceptional circumstances where there are particular difficulties in achieving an adequate bathing temperature.

Temperatures as listed in – The HTM 04-01: Safe hot water in healthcare premises. Part A: Design, installation and commissioning practices (table 2 page 55)


How Often do TMVs Need Servicing?


TMV Servicing is needed “Where the risk assessment considers fitting TMVs appropriate, the strainers or filters should be inspected, cleaned, descaled and disinfected annually or on a frequency defined by the risk assessment, taking account of any manufacturers’ recommendations.” HSG 274 – p.2.164

Regular TMV servicing and maintenance check, temperature monitoring and failsafe testing is required to ensure your TMV’s perform at the NHS Model Engineering Specification Level. If a valve fails a TMV servicing and maintenance test, the valve must either be serviced in accordance with the NHS Model Engineering Specification, or if it can not be serviced it should be replaced.

Regular & on-going TMV servicing maintenance tests and failsafe testing should be carried out to demonstrate adequate thermal performance is being maintained. Get in touch to book your TMV servicing maintenance!

What is Included in TMV Servicing?


Visual Inspection

Review the installed TMV to ensure correct specification valve is installed where required.


Temperature Control

Undertake temperature check and re-calibrate where required.

Failsafe Test

Ensure TMV failsafe mechanisms operate correctly to protect users in the event of water supply failure.

Clean, Descale & Disinfect

Clean, descale and disinfect any strainers or filters.

Service Process

Get a Quote

Get a quote today by phone, email, or complete our contact form to receive a quotation within 24 hours.


Our coordinator will be in touch to confirm a Date That Suits You, along with estimated time of arrival.

Your Appointment

On the day of your appointment, you will receive a 30 min Curtesy Call from an engineer to confirm they're on route.


Your report is then Quality Checked and emailed in PDF Format, with Next Day Delivery.

Support Call

Our support team will be in touch to arrange your free 30 min Support Call to help explain your report.

All payments are due prior to booking completion unless agreed in writing for 30 days from the date of invoice. We will hold your booking time for 24 hours whilst we await payment. Reports are typically next day delivery, but please allow for up to 5 working days delivery.

Your Dedicated Water Hygiene Team

water quality monitoring


Customer Service

water quality monitoring



water quality monitoring



Legionella Control Services


Sales Manager

TMV Servicing FAQs

How Does a TMV Mix Hot and Cold Water?

A TMV regulates water temperatures using a mixed water temperature system. Landowners with hot water outlets must ensure a TMV3 valve is fitted. This will result in the set temperature of the building’s water supply meeting the UK safety standards for water outlets. Moreover, isolating the cold water supply with regular failsafe testing to ensure reasonable water temperatures is required. This ensures the safety of vulnerable persons who could be affected by overly hot water temperatures.

What are the Health and Safety Regulations for Thermostatic Mixing Valves?

The set temperature for hot water outlets usage in social care services is between 39’c and 43’c or lower. When it comes to TMV health and safety regulations for hospitals, healthcare services and social care services, the primary means of controlling the growth of Legionella Bacteria in hot water systems is using hot water temperatures. Current guidance set by the Department of Health states that hot water used in social care services should be stored at a minimum of 60°C and used mixed with a cold water supply at a minimum temperature of 55°C. Regular TMV cleaning, descaling and disinfection is required by health and safety laws.

What are the steps in TMV Servicing and Maintenance?

Water quality standards must be maintained and regular valve components services must be conducted to ensure you are managing the risks of legionella correctly. Remedial works and services can be used to check the fine mesh of TMV3 Valves when you service TMV. Ensuring your water quality standards, safe water temperatures and safety standards are meeting the standards that the NHS sets is a necessity. TMV Water treatment also includes remedial work like cleaning, descaling and disinfection.

When and How Often do I need a Risk Assessment?

Under the Health and Safety at Work Act 1974 and in compliance with the Approved Code of Practice (ACoP L8, HSG 274), duty holders, including employers and those in control of premises, must ensure the health and safety of their employees or others who may be affected by their undertaking, this includes a legionella risk assessment

Precautions must be taken to prevent, manage and control the risk of exposure to legionella. Including regular water treatment, maintenance & monitoring, water cleaning, temperature monitoring, descaling and disinfection. You can do this by undertaking the following: a legionella risk assessment by water treatment and engineering experts. Get a free legionella audit with us today!

Do uRisk Service my Area?

Yes, uRisk’s services are nationwide. Whether you have one or multiple water systems or sites. We service TMV & TMV3 Valves across the country. With qualified engineers offering remedial works & services scattered throughout the UK. Our offices are based in Hertfordshire which is a 30-minute train journey to London King’s Cross.

Why choose uRisk?

25 Years Experience

Over 25 years of water hygiene and legionella control experience.

Customer Service Excellence

Friendly and simple advice by phone, email & online at your convenience.

City & Guilds Qualified

All staff are trained water hygiene consultants and engineers.

Nationwide Coverage

With engineers located all across the UK, we're never too far away.

UKAS Accredited Testing

Our labs are UKAS approved providing you with quality assurance.

Full Compliance Services

Your one stop shop for Legionella control, no need to go elsewhere.

This is by far the best service I have received in a long time.Lloyd who we spoke to was super helpful and very thorough with everything.I would def recommend using this company, they are not just out for money they put their customers needs first.Thank you
Coral Dawkins
Coral D.
uRisk have been helping us with our Legionella Control for a number of years now. We've recently had a CQC audit and they were very impressed with our legionella compliance! Thank you for all your help.
Mike Port
Mike P.
Brilliant service! Thanks a lot for the hard graft
Leon Macauley
Leon M.
We have been working with Urisk for best part of year now. I could not recomend their services highly enough. They always promptly respond to our requests promptly and manage the job from start to finish seamlessly. I would highly recommend.
Sam Guest
Sam G.
Brilliant company, customer service was great! And engineers were fantastic. Thanks again uRisk! Will definitely be using them for all future work.
Nikesh Gohil
Nikesh G.
Incredibly detailed and professional team. Have been beyond helpful with with our CQC legionella compliance for our Safety. They’ve found solutions to fit around how we work and our budgets. We are always advised with reference to HSE which has been brilliant.
Amy Thorne
Amy T.
Richard & Nick are great. Really good work and nice people.
Joshua Ballard
Joshua B.
A fabulous company, excellent customer service, they try to accommodate appoitments, and do there utmost in emergencies, been with them a few years now,  honestly cant fault them. Coming out of Covid 19, having our building urgently disanitised,  big thank-you to Luke and Lee for staying so late to get the job done!! Thank you Devon, for juggling the diary to fit us in so soon. A Team 🙂
Jo Maskell
Jo M.
Fantastic training courses and we've found the legionella risk assessment very easy to read and far more detailed than any we have previously had. 5 star service!
Gemma Pond
Gemma P.
My first time using Urisk for work at multiple sites. Daniel was absolutely brilliant, polite and professional. Highly recommended! 🙂
Claire Keay
Claire K.
We're a small GP practice and started using uRisk for legionella risk assessments. We opted to use their remedial and monitoring services and they've been absolutely great. We cannot recommend them enough! Thank you so much!
Amanda Pates
Amanda P.
Extremely happy with our legionella risk assessment carried out by uRisk, easy to understand and great customer service. Thanks again
Nickayla Robertson
Nickayla R.
My experience with URisk Water Hygiene from my initial enquiry, to their site visit to undertake a Legionella Water Risk Assessment at my office (MDG), to providing me with the report and aftercare has been superb! Efficient response times, excellent customer service, friendly, helpful advisors and assessors who are always ready to help and provide guidance. An absolute pleasure to deal with, I highly recommend!
Lauren Wakeman
Lauren W.
Brilliant Service, efficient, professional, punctual and friendly.
Alex Windsor
Alex W.
Really easy to organise a risk assessment to be carried out at our offices and have had great help from them since to implement the necessary changes to keep the office safe. Would definitely recommend.
Holly Ferguson
Holly F.
Daniel did the testing today at PGHC He was really efficient, friendly and so professional. An absolute pleasure to deal with. Thanks Daniel
Lorraine Carruthers
Lorraine C.

We want to help you comply!