TMV (Thermostatic Mixing Valve)
Also known as blending valves. A control that can
(or in some cases must) be installed to the incoming hot water pipe
feeding a bath or basin to avoid the risk of scalding for the user.
How does a TMV work?
TMV can be adjusted to a set temperature. Should incoming water arrive at
the valve any hotter than required the valve automatically blends cold water
into the feed to reduce the output to the set temperature.
The TMV scheme is a government initiative and will eventually become law. It
is wise to fit TMVs to all domestic outlets, especially where the very young
or the elderly will potentially put themselves in harms way. Every year
children die an agonising death by falling into baths during filling where
the water temperature is dangerously high. Elderly people with reduced or
delayed sensation are prone to scalding because they simply can't react
quick enough to realise water is too hot.
Walk in bath safety
are becoming very popular with the elderly and persons
who suffer from limited mobility. Just imaging the horrific nature of the
injuries one would risk if you climb into the bath, close the door, then
open a tap to be showered with scalding hot water! A Walk in bath that is
not protected by a TMV is rather like playing Russian Roulette. Don't ever
let anybody tell you it will be OK - it won't! Cutting corners to save a few
pounds is utter stupidity. Just think, you install an expensive walk in bath
to make life more comfortable then you risk burning your feet!! Questionable
logic at best.
Thermostatic mixing valves - the difference
The TMV Scheme awards a number based on performance. Basic control is
offered by a TMV whereas a high level of control is opffered by a TMV3.
valves with maximum temperature stop (including single lever taps).
thermostatic mixing valve of lesser
performance to D 08 which conform to EN 1111ís and 1287 (originally BS 1415
Part 2). These can have a maximum temperature stop which is excluded by the
requirements of D 08.
thermostatic mixing valve with enhanced
thermal performance complying with NHS Estates requirements.
There are two factors to consider when choosing a blending valve.
The performance level 1, 2 or 3.
The flow rate through the valve when
The flow rate is a particularly important factor when choosing a valve for
example to serve a walk in bath. The flow rate is how fast the valve can
deliver regulated water. Consider, if you were sitting in a bath waiting for
it to fill you would be glad for it to do so as quickly as possible. It is
therefore important to choose a TMV3 valve with a high potential flow rate.
This is where you will pay more for one valve over another. As a rule of
thumb, the dearer the valve the better the control function and the higher
the potential flow rate or throughput of water.
TMV2 and TMV3 Valves are an essential safety
feature to ensure water cannot reach taps at an unsafe temperature. By
incorporating a Thermostatic Blending Valve you can prevent accidental scalding and injury.
TMVs are easily
easily installed and represent a sound investment if you truly care about
For further information on the TMV
Scheme and the classifications please