What is the difference between vacuum relief valve and a vacuum breaker valve

Hi Woodpens...

A vacuum relief valve, such as the watts valve below (see image with black top hat), is used to prevent vacuum or backflow conditions in a water heater. A vacuum breaker (see image) is primarily used on outside water faucets... also used to prevent backflow conditions. These are not interchangeable.

The other relief device on a water heater is a TEMPERATURE AND PRESSURE RELIEF VALVE (see other image). This relief valve is a safety device that operates to protect the water heater from experiencing dangerous fluctuations in temperature or pressures. For example, if a water heater gas valve failed to shut off it would cause the water to overheat and expand. The T&P relief valve would discharge the water to a safe place (the floor or a drain) and help prevent an explosion of the water heating vessel.

To see what can happens when a T&P relief valve malfunctions click on Water Heater Blast!.

More questions? Let me know, OK?

Mark