HOT WATER SUPPLY: Our vacuum relief valve is designed specifically to protect the hot water supply system where over-pressure conditions are likely to occur as a result of thermal expansion DOMESTIC AND COMMERCIAL APPLICATIONS: Can be used for both domestic household and commercial job site applications COMPLETELY AUTOMATIC: The VR20 Vacuum Relief Valve reseals after pressure relief INSTALLATION: The valve may be installed directly on the tank or in a tee and is appropriate for either side (hot or cold) of the water heater PRODUCT SPECIFACTIONS: Fitted with a bronze body and has a stainless steel internal part, silicone seat disc and stainless steel pressure spring