Hot Water Tempering Valve
A tempering valve restricts the temperature of hot water that is delivered into your home from your hot water system, which helps to prevent injuries such as scalding.
In many Australian states, you are now required by law to install a tempering valve when you install a new hot water heating system. While your tempering valve may have the ability to be set higher than 50OC, this goes against Australian standards.
The tempering valve is fed by the hot water and cold water pipes and mixes the hot and cold water with a temperature monitor that makes sure that the temperature doesn’t go above 50ºC.
Using a temperature sensitive element submerged in water, the thermostatic element, the 3-way mixing valve can selectively open and close pipes to allow hot and cold water in. It does this by expanding and contracting in response to temperature changes. This controls a piston which opens and closes the hot and cold inlet pipes, thus regulating the temperature.
The ratio of hot and cold water is varied so a temperature of 50ºC can be achieved. Tempering valves are accurate within 3ºC.
Your plumber sets your hot water storage tank to heat water to a minimum of 60ºC and installs a tempering valve after this, set to 50ºC. By mixing cold water to temper your hot water down to 50ºC, you decrease your hot water usage and thus decrease your hot water demand.