AC Adapter humming

I have only had my Rachio 3 for 2 weeks and the adapter is humming quite loudly. I have plugged it into another outlet and got the same results. Is this a common issue?

Thanks for any help with this.


Sounds like it may have gotten damaged in shipping. Some low-level humming should be expected but if it’s clearly audible the transfer core may have gotten a bit loose.
Since your unit is new, I’d contact Rachio Support (, they are usually pretty good with RMA process.
If the vibrations (which result in humming) are causing transfer to warmup to a significant degree, you may want to consider stopping it’s use until replacement arrives, otherwise if transformer is close to ambient while idle and plugged in, I don’t expect you’d run into any major issues.

This happened to me with a new Gen 2 a couple years ago. Support replaced it.

Probably not the issue, but you might confirm your 120v outlet is wired properly with a circuit tester, i.e., hot is hot, ground is ground, and common is common.