Back flow preventer vs bigger anti siphon valve.

[mxnerd]

Is there really a difference?

I have an existing PVC pipe sprinkler in ground with anti siphon valve.

It's old and leaking and there is no timer.

I would like to add a hose timer with a simple back flow preventer.instead replace the old anti siphon valve.

Will that be OK? What's the difference?

https://www.walmart.com/ip/B-K-108-904RP-Backflow-Preventer-Vacuum-Breaker-3-4-in-MPT-Brass/38471329
vs
https://www.homedepot.com/p/3-4-in-150-psi-Anti-Siphon-Valve-with-Flow-Control-L7034/100062989

 

[Greenman]

They're different versions of the same thing. The one that screws to the hose bib is required by code around here. They work, but in some conditions they emit a very loud hum that travels through the pipes. It will make you nuts (assuming that isn't a preexisting condition).