by marrtin »
Fri Jan 11, 2008 11:33 pm
What makes this terrible tragedy even worse, is it could easily have been
prevented given some basic understanding and a few simple checks. Header tanks are designed to withstand a temporary overflow of boiling water without failing, and it is reasonable to suggest the fault in this particular case could have been occurring for some weeks probably even months before the tank finally collapsed.
In this instance, the immersion heater thermostat failed causing the element to continually heat the water in the cylinder until it reached boiling point. The resulting steam escaped as expected up the expansion pipe into the header tank taking with it quantities of boiling water. Cold water from the header tank would be drawn in to the system via the feed pipe to replace the water expelled from the expansion. Eventually, this continual cycle resulted in the water in the header tank reaching close to that in the cylinder below. Eventually and unfortunately, the tank now full of boiling water finally buckled and failed.
Symptoms.
1. Exceptionally hot water from hot taps often discoloured and having an unusual odour.
2. Loud noise from the cylinder similar to a kettle as it approaches boiling
point.(maybe only noticeable after 2am or 3am if the water is heated using a cheaprate electricity tariff.)
3. Loud banging noise from the heating pipes.
4. Water in the header tanks very warm or hot after the heating has been on for several hours.
5. Considerable condensation in the loft during winter months.
The only way to be totally sure is to periodically examine the header tank(s) and ensure the water is always at ambient temperature.