TMV Servicing
What is a TMV?
TMV stands for Thermostatic Mixing Valve. It’s a valve that blends hot water with cold water to ensure a constant, safe water temperature at the outlet, typically for outlets used for handwashing, showers, or baths. TMVs are most used in settings like hospitals, schools, and public facilities, to prevent scalding or discomfort due to sudden changes in water temperature.
Why do TMVs need servicing?
Thermostatic Mixing Valves (TMVs) need servicing for the following reasons:
- Ensure safety features are working/preventing failures.
- Reduce the risk of Legionella.
- Extend the lifespan of the valve.
- Maintaining performance/replacing damaged parts.
How often should TMVs be serviced?
TMVs should be serviced as a minimum at 12 monthly intervals. However, this may be more depending on other factors such as:
• Manufacturers recommendations.
• Risk assessment suggestions.
• Usage.
• Regulations (healthcare for example).
How long does it take to service a TMV?
Accessibility, condition, and surrounding pipework can all affect the time it takes to service a TMV, in general accessible TMVs will take approximately 30 minutes to service and reinstate, however it may take longer depending on issues encountered during the service.
What issues might be found?
Some of the common issues include:
• Inaccessibility of the TMV (making it difficult or even impossible to service).
• Lack of isolation valves either side of TMV. This may mean the TMV is not able to be serviced without prior installation of suitable valves.
• Poor flow rate from the outlet. This may indicate a blockage within the TMV that may be fixed during the service.
• Fail safe not operating. This could lead to scalding in the event the cold-water supply to the valve is disrupted.
• Incorrect output temperature. This can be recalibrated as part of the service.
How are TMVs serviced?
Servicing a TMV involves maintenance tasks to ensure its proper functioning and safety. Followed by a tear down of the components; to clean, disinfect and replace any damaged parts. Here’s a general guide on how we would service a TMV:
• Safely remove panels, furnishings, and equipment to allow access to the TMV.
• Take and record temperature of the blended output, as well as the hot and cold incoming temperatures via pipework temperature probes.
• Perform a fail-safe test by shutting off the cold-water supply to the TMV. The water supply from the outlet should shut off, if so, the fail-safe is working correctly.
• Isolate the hot and cold feeds via isolation valves on both feeds. Then open the outlet to confirm the valves are operational.
• Remove TMV from associated pipework and check visually for issues.
• Inspect the internal components of the TMV for any signs of wear, corrosion, or damage.
• Remove strainers where possible and place all components in descaler and disinfectant.
• Take photographic evidence of TMV and all components cleaned.
• After replacing any damaged or worn components, reassemble and reinstate the TMV, open isolation valves and test for leaks, correct blended temperature from the outlet and that water flow is consistent.
• Complete another fail-safe test, logging the result.
• Adjust temperature if required, log any faults found and complete report for client, including any remedial recommendations.
Can I service my own TMVs?
Whilst it is possible for self-servicing of TMVs, if you’re not experienced with water systems, or if there are a large number of TMVs, it’s advisable to have an experienced technician to service them to ensure compliance and proper functioning.
Contact us on 0800 243 471 or email info@swiftclean.co.uk for a quote or some expert advice.
