Irrigation pipes banging when toilet flushed

[marlonc497]

Thanks for the suggestions, I'll do them as soon as I can. Does anyone know why the backflow valve would chatter continously until I shut the zone or valve down?

 

[Twowaxhack]

Thanks for the suggestions, I'll do them as soon as I can. Does anyone know why the backflow valve would chatter continously until I shut the zone or valve down?

Every zone valve or just one ? If it’s just one then it’s a bad zone valve most likely.

 

[Twowaxhack]

Choke the outlet of the backflow device going to the zone valves some.

Large inlet pressure drops can cause chattering. By choking the outlet it may help the valve maintain inlet pressure.

Experiment with how much. Monitor for noise.

Also choke the flow rate down on the toilet, make it fill slower.

See if that doesn’t stop the trouble.

 

[marlonc497]

Will do, its been raining today so the cycle got canceled but ill monitor it the next time it runs. Thanks!

 

[marlonc497]

Quick update, per Twowaxhack's recommendation I choked the outlet of the backflow preventer about halfway and since then I've had no chattering (knock on wood). The backflow preventer still "locks up" for a split second when either zone 1 or 4 turn on so I suspect it must be faulty zone valves closing or opening too quick. Nonetheless the main problem was the chattering and it seems to have been solved. Hoping no one touches the outlet valve now that it's working haha.

 

[Twowaxhack]

Thank you for the update. It was a guess on my part so this was definitely a learning experience for me.