Some valves just reach the end of the road. The cartridge is scaled solid, the parts are discontinued, or it was never the right valve for the job. Sometimes there wasn't a TMV at all and there should have been. Either way, we'll fit one properly.
When it's time to replace rather than service
- It keeps failing the fail-safe test even after a strip-down and new parts.
- Parts aren't available. Older valves in London's 1980s and 90s refurbishments often fall into this camp.
- It's the wrong type. A domestic TMV2 valve doing a TMV3 job in a care home, for example.
- It can't be reached. Tiled in with no access panel, so it never gets serviced. A valve nobody can get to is a valve nobody checks.
- It drifts every time. If a valve won't hold temperature between services, the replacement often pays for itself in callouts.
TMV2 or TMV3?
Both are third-party approval schemes for thermostatic mixing valves, and the one you need depends on who's using the water.
| Scheme | Typical use | Standards behind it |
|---|---|---|
| TMV2 | Homes, HMOs, flats and general domestic-type settings | BS EN 1111 (high pressure) and BS EN 1287 (low pressure) |
| TMV3 | Healthcare, care homes and other settings with vulnerable users | The NHS performance specification used for healthcare (D08), referenced in HTM 04-01 |
Plenty of valves carry both approvals. What matters is that the valve is approved for the way it's going to be used, including the supply pressures on your site. In London that varies a lot: a gravity-fed system in a Victorian terrace behaves nothing like a boosted supply in a 20-storey tower. We'll check before we specify.
More background is in our TMV compliance guide.
How we install
- Survey. Outlet type, who uses it, supply temperatures and pressures, and where the valve can go so it's reachable.
- Specify. The valve type and approval, isolation valves and strainers, and an access panel if there isn't one.
- Fit. Neatly, with isolation either side so future servicing doesn't mean draining half the building.
- Commission. Set the mixed temperature for the outlet, carry out the fail-safe test and record the results.
- Hand over. A commissioning certificate, the valve added to your asset register, and dates booked in for the first in-service tests.
Fitting close to the outlet
The mixed water between a TMV and the tap sits at a lovely warm temperature, which is exactly what Legionella bacteria like. So the guidance is to keep that run of pipe as short as possible. We fit TMVs close to the outlet wherever the building allows, and we'll point it out if an existing valve is serving a long dead leg or several outlets in a way that worries us.
London buildings we fit in
Mansion block bathrooms with lath and plaster walls. New-build flats where the TMV is hiding behind a magnetic panel nobody knew about. Care home en-suites, school washrooms, clinic hand-wash basins and hotel bathrooms. We plan the access and the mess so the room's back in use the same day wherever possible.
Common questions
Do I need a TMV on every tap?
Not necessarily. It depends on who uses the outlet and your risk assessment. Baths in new homes need a device to limit the hot water temperature under Building Regulations Part G, and healthcare, care and education settings usually need TMVs on outlets used by vulnerable people. We'll look at your building and give you a straight answer.
Can you fit a TMV under a sink in a small flat?
Usually, yes. Compact under-basin valves are common. We'll make sure there's room to get at the strainers and isolation valves later, otherwise you're just storing up trouble.
Can you replace a valve like-for-like?
Where the existing valve was right for the job, yes. If it wasn't, or the model's discontinued, we'll suggest the closest suitable replacement and explain why.
Got TMVs in London that need a look?
Tell us roughly what you've got and where. We'll give you a fixed quote and a date that works around your building.