Well the inner workings of hot water systems are made to heat up the water- right? Yes, but there is a point where it can be too much and actually damage your heater.
Why is it bad for your hot water heater to overheat?
Waters at high temperatures are potentially dangerous as hot water obviously burns, but can also be dangerous to your hot water heater. If the hot water boils over or even overheats more than what is recommended in your cylinder it can dramatically reduce the life expectancy of your hot water heater.
It reduces the life span by creating tiny cracks in the vitreous enamel lining on the inside of the tank, with prolonged overheating these cracks will become worse and worse. Once the vitreous enamel has been eaten away over time the water will then start to eat at the steel tank cylinder.
Safeguards to stop this
For electric hot water heaters, the primary form of protection is an ECO or energy cut out. Inbuilt into the thermostat of the hot water heater is a temperature disc. This temperature disc discharges at the setting of around 85 degrees depending on the type and brand of thermostat. (The most common brands of thermostat in the marketplace are the Klixon and Robertshaw) When this energy cut out activates it de-energises the element to stop the water heater from heating anymore. At this stage, you would soon have no hot water and need to phone a technician at Same Day Hot Water.
For gas hot water heaters, the unitrol works as their primary form of over-temperature protection. At temperatures ranging between 70 and 85 degrees (depending on the brand and type of controller the most common in the marketplace being Robertshaw and Eurosit), the ECO will activate cutting the gas off. At this stage, you can make a phone call to us here at Same Day Hot Water for us to get you back in hot water!
The secondary form of over-temperature protection is done through the pressure-temperature relief valve. The relief valve usually has a setting between 95 and 99 degrees before it fail-safes and dumps water to cool down the tank. It does this through a wax element inside the valve detecting temperature high temperature and opening up.