Avoid Water Heating Thermostat Failure

The inquest jury on the case where a baby was scalded to death when a water tank ruptured above her cot has blamed the government for the failure.

In 2002 a health and safety inspector has warned the government of the danger of such systems when a woman was badly burned in similar circumstances.

Ten-month-old Rhianna Hardie suffered 95% burns when a water tank in the loft above her bed burst covering her in hot water while she was sleeping.

Professional plumbers are aware of the problem of outdated thermostats, one of which caused this disaster. Plumbers and heating engineers are encouraging the public to check and where necessary to replace the old thermostats with new model that have additional level of protection.

According to leading plumbers and heating engineers, replacing the immersion heater and thermostat to a new model is a fairly simple job and should minimise the risk of such fatal accident that happened in November 2006.

The set up at Rhianna’s home was such that when the thermostat failed, the immersion heater kept heating the water inside the hot water cylinder. Since there was no back up cut-out loop, the water kept heating up. As the plumbing system was a vented (open) system, boiling water from the cylinder rose up into the roof tank. In the older systems, most plumbers installed copper cylinders which can cope with high temperatures. However, the loft tank is made of plastic which is only rated to hold water up to 25c. As the boiling water rose up from the boiling cylinder, the loft tank split and the water forced its way down.

Currently plumbers are installing tanks that meet new and stringent safety standards where they are rated to hold boiling water for up to 500 hours. As the system at the Hardie household was installed in 1973, the system was old and not up to the new standards.

As of April 2004, all plumbers and heating engineers have been instructed by the British Standard Institute to only use immersion heaters that have a modern double safety trip.

Leading plumbers and heating engineer highlighted several warning signs that a thermostat is failing:

• Excessive hot water from the taps
• Loud noises (bubbling noises) from the hot water tank (normally in the airing cupboard)
• Hot water coming out of the cold water taps
• Condensation and steam in the loft

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This page has been written with contributions from plumbers from Berkshire and qualified plumbers from Tonbridge. Several of the company's experienced plumbers from Essex have worked on similar issues as well as some of our Gas Safe engineers from Bolton and our Greenwich experienced heating engineers.

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