What are the concerns with thermal expansion and backflow prevention?
Since backflow prevention devices prevent the exchange of water between the customer and the public water provider that prevents thermal expansion, a pressure blow-off valve must be provided at the hot water tank. Blow-off water should be directed to a proper drain. Gas fired hot water tanks have a tendency to build pressures quickly and these pressures can rupture internal plumbing. Customers are advised to contact a local plumber to correct these situations.
