Unregistered

Do isolating valves prevent water backflow.

ajs heating

no a check valve does that

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ProffesorPlumb

There are different backflow prevention devices for different scenarios.

Water Regulations are very strict on where these are installed. It is a legal offence to not use the correct backflow prevention on a system if its needed.

SteveO

NO. A single or double check valve will do this as per the water regs.

sibs

In what circumstances would you need either a single or double check valve to prevent backflow?

chawkey@hotmail

depends on what fluid category you are dealing with, outside taps you should use a double check valve as a hose pipe could be connected to it and so increase the risk of backsiphonage. There are all also RPZ's which are used for zone protection mainly in comercial premmesis, but for domestic best to use a double check valve if in doubt