The Waterco vacuum relief valve

A valve must be installed in every solar heating system to allow air into the system when pool water drains out of the panels. This relieves the vacuum that would be created by falling water inside the solar panels and plumbing on the roof. There are various styles of vacuum relief valves, but all automatically allow air into the system when there is a vacuum created by a void of water pressure. We in the industry refer to a vacuum relief valve as a PRV.