Posted By Malcolm Greenhouse
Reference the tragic case of the scaling of the little girl in the West Country. The news reports that there is a modern thermostate that will fail to safe when it develops a problem. In my experience the problem is usually that the contacts that should part when the thermostate becomes too hot are actually welded together through electric arcing. The question is therefore can anyone explain how the modern thermostate works and stops this from happening.

Posted By Bob Shillabeer
Please stop this Government bashing. The fault was the thermostate failed to cut the supply to the heater. Tragic yes, but who is at fault. The Government department for not acting on the original coroners warning, possibly, but what about those who set the standard for this type of devise, again possibly. The matter is how many of these devises are still in use, what if the Government decided to ban them, based upon one case?? Where does the balance of judgement come in? There could be hundreds of thousands of these devises in use throughout the country, would this be reported as a safety issue or one of over reacting?

From a purely safety consideration there is a possibility that this sort of incident coyld hapen again, the Gvernment has a decosion to make does it allow this type of thermostate to continue to be used or should it instigate a repalcement process, who would pay for it, the taxpayer?

May I suggest that when such systems are maintained the maintenance regime should include a test of this devise and a warning to say they should be replaced as a precaution. This would cover most applications along with local authorities being responsible for thier check and replacement in houses owned by that authority.

Posted By Malcolm Greenhouse
Thanks to the people who have responded. My understanding now is that modern thermostat has two controls in series, the on/off temperature controlled contacts that fail on occasions, usually following arching with the contacts welding themselves together and the higher temperature cut off that having operated can only be physically reset. The difference here is that whilst the on/off contacts are operating continually as the water heats and cools(hence the possibility of arching with age) the cut off only operates very infrequently unless a fault condition is becoming apparent(far less change of arching.

The annoying thing about all this is that when the maintenance people in my housing association started to discuss how we should react to the events highlighted in the last weeks it became apparent that we had already had two similar incidents in the last two years in our housing stock of 6600 properties. Thankfully no one was injured but also no one had reported it to the health and safety section as a dangerous occurrence. I think that I will now be using this example as a means of highlighting the importance of near miss and dangerous occurrence reporting.

What are we going to do about it? Well I think it would be seen to be reasonably practical for the organisation now to change all of the old thermostats to the newer version. The most economical way to do this will be to combine the exercise with other visits already taking place to properties and the annual gas/flue checks that we have to perform would appear to be the most appropriate. This will therefore be my recommendation.