Whatever the requirement Tough Water Solutions Ltd will work with you to complete the works

Thermostatic Mixing Valves are designed to blend hot and cold water together at the outlet point so that the water is at a safe temperature to use. Also as an anti scold device so that the valve shuts off if the cold water becomes isolated.

In order for them to work correctly they require servicing on a regular basis after they have been installed, ideally every 6 months as they can become blocked or limescale may have built up – effecting the quality of the function.

Tough Water Solutions carry out TMV Servicing, management and installation – we can also answer any queries you may have!

Thermostatic Valves: How they control the risk of scolding

(If people are supported to bathe or shower there is a risk they may be scalded. Water at or above 45 degrees C can scald.)

Thermostatic valves are a mechanical means of limiting the temperature of water coming from a bath, basin or shower head.
TMV3 type valves are fitted to the pipe just below the tap within 0.5 meters of an outlet. The valve mixes hot and cold water to a pre-determined temperature.
TMV3 type valves are tamperproof. Once they are set by a plumber, the pre-determined maximum temperature cannot be altered without a visit by a plumber.

Safe water temperatures

The safe maximum temperature for a bath tap is 44 degrees C, by the time the bath fills, the temperature of a full bath may have fallen to 41 degrees C.

The safe maximum temperature for a shower is 41 degrees C because the water is directed at the thin and sensitive skin on the scalp.
The safe maximum temperature for a hand basin is 41 degrees C and for bidet it is 38 degrees C.

Risk Factors – is a valve needed?

Can a person tell the difference between hot and cold?                                                YES/NO

Can they recognise the risk from water that is too hot?                                                 YES/NO

Are they able to physically remove themselves from water that is too hot?               YES/NO

If the answer to any questions is NO then a TMV3 valve is needed.

If TMV valves are indicated for only one person in a shared house, then a valve should be fitted to baths/showers which they will use.

The limitations of TMV2s and why not to use with venerable persons

TMV2 type valves do not offer the same degree of protection because they are characterised by a small over-ride button (usually red or silver) on the tap.

TMV2 valves are commonly found in hotels where the tap is marked with numbers and the over-ride button is usually positioned between 38 degrees C and 41 degrees C.

The over-ride button may be depressed on purpose or by mistake and so a TMV2 type valve does not sufficiently control the risk.

Thermostatic mixing valves: Servicing

Manufacturers of TMV3 type valves recommend that they are serviced regularly to ensure they are working as designed.

Manufacturers can supply details of how too and how often the valves should be serviced.

TMV servicing should only be carried out by a qualified competent plumber.

All TMV valves are different but standard procedure is to:

  • Isolate hot & cold inlet supplies.
  • Disconnect the main valve body from the pipe work and clean the filters.
  • De-scale and disinfect the TMV valve and parts.
  • Clean the valve and connect back together.
  • Turn water supplies back on and test for leaks.
  • Turn hot tap on fully and run for 30 seconds and test check the temperature is within guidelines?
  • Adjust if required by using specified tools or keys to specified temp.
  • While tap is still running turn the cold supply off and check fail safe? = PASS/FAIL
  • If valve fails isolate the valve from use and inform responsible person.
  • Complete a TMV service sheet and report any faults to responsible persons

Older valves when disconnected and stripped can sometimes cause faults and damage the valves function so where a valve has passed its fail safe test and temperature is within guidelines and flows is sufficient then most plumbers will not strip or disconnect the valve to prevent any damage while the valve is safe and working correctly.

All manufacturers should have information on how to service there valves if required.

Important: action to take

You must take action if the water is too hot.

More than 44 degrees C from a bath

More than 41 degrees C from a shower or hand basin

  • If the water is too hot, record the temperature in a check sheet
  • Call a plumber and arrange for them to attend as soon as possible to check and reset the valve.
  • Stop anyone using the bath or shower until the plumber has called
  • Tell your manager and colleagues what you have done and why.
  • If bath/shower is needed for personal care before the plumber can attend, work out as a team how you will protect people from scolding until then.
  • Record the temporary safe system and ensure all staff members read, understand and sign it.

Tough Water regularly come across sights just like the images below. This is a TMV we were servicing and it was discovered that the TMV didn’t actually work, we dismantled it and the reasons were revealed as to why it no longer worked – I think the images say it all don’t you?

This is a TMV that hasn’t been regularly controlled and serviced, as they’re an anti-scold device, it is extremely important to have them regularly serviced in order for them to work correctly and efficiently.