A tempering valve mixes hot water with cold water to deliver tempered water at a constant temperature throughout an entire house.
Why do I need it? A tempering valve is one of the best ways to ensure people are not harmed or scalded by hot water when it comes out of a tap. It works as a mixing tool, as it combines both cold and hot water to correctly produce the required water temperature to be released from a particular outlet.
It is a requirement under AS/NZS3500.4:2003 in NSW that a tempering valve be installed when replacing a hot water heater.