1560 Vacuum Relief Valve - Water Heaters - Introduction -

Image Text: Cross section > vacuum relief valves are installed in some jurisdictions to prevent hot water from backing into the cold water lines in the event of a cold water pressure drop > they also protect against possible collapse of the storage tank by preventing a vacuum from forming inside > floor framing > foundation wall > water meter > gas > gas water heater > cold > hot > cold water supply valve > vacuum relief valve > hot > cold