Water Hammer on One Zone Only

Hi all - Been using multiple Rachio controllers for many years now. Recently I started to get insanely loud water hammer after one specific zone closes. I have the Minimize water hammer feature selected. I installed a water hammer arrestor near the valve box but it was no help at all.

The only change that completely resolved it was removing the offending zone from the full schedule and just running it by itself. This isn’t the end of the world but it does make management a bit more of a pain. My larger question is why would this help anyway? I’ve read alot on the topic (like this) and I can’t seem to understand why running the same zone for the same time outside of the regular schedule would have any impact at all. Also I can’t figure out what would have caused this as its been fine for 7 years.

Thanks for any pointers!

I had a bad water a number of years ago (not using Rachio at that time). I put in a hammer arrestor as well that did not help. I was told the speed at which the valve turns on/off makes a difference, so I put in a better valve and that helped quite a bit. With that said, maybe the valve is getting worn???

Could be but then why would there be no hammer when the zone runs separately from the rest of the zones? (Also I dont know how to change a valve so trying to avoid that :wink:

That does sounds odd to me. Where is the zone within the schedule (beginning, end, or somewhere between)? If it is not at the end, I wonder if that zone shutting down when another is beginning is contributing . . . you might try putting that zone at the end.

Yep - I’ve tried it first, last and in between others and no luck. Only time it is good is if it is entirely on its own…

Sounds like you are a few steps ahead of me, great job. I am not sure what else to try other than I might try playing around with the valve manually (not with the controller).