Backflow Prevention for Solar Domestic Hot Water Systems

The Building and Safety Policy Branch has recently published an Information Bulletin that clarifies the BC Building Code requirements pertaining to backflow prevention for solar domestic hot water systems.

The bulletin indicates that CSA F379.1 allows the use of a single wall heat exchanger with a dual check valve with atmospheric port for systems with a non-toxic heat transfer fluid or potable water. If a double wall heat exchanger is used in any system a backflow preventer is not needed unless a make-up water connection is provided to the heat transfer loop.

It is important to note that the BC Building Code does not address the cross-contamination requirements outside of the building. The water purveyor sets the backflow prevention requirements at the connection between the municipal potable water system and the home.

The requirements for solar domestic hot water systems are set by plumbing inspectors in each municipality and contractors are required to contact the municipality to find out the requirements for backflow prevention for the installation of solar domestic hot water systems.

To read the bulliten click here.