It’s not nuts, @MastaBlasta. It simply suggests your old WiFi network was the problem.
When you write “To my surprise, the Rachio showed up as a new accessory in HomeKit.”, do you mean it never showed up before? At all? If so: That suggests to me your old WiFi network was not properly propagating network services advertisement/discovery protocols.
The surprise is my HomeKit with Rachio failed right after an iOS update a year and a half ago. Rachio was and is the only HomeKit accessory that stopped working with my old network. So yeah, it is still crazy… crazy that Rachio’s HomeKit implementation is such a cluster F. I was about to return my Rachio to Costco but since it works currently with my new network, I’ll hang onto it to not go through the hassle.
Also, sorry if I seem a little on edge. I truly think Rachio doesn’t have the proper personnel to understand or implement HomeKit. I was patient and backing them up over a year ago. Now, this is ridiculous. I work in IT and have plenty of experience with HomeKit and networking. I’m just a frustrated customer at this point and I know I’m not alone. I guess at this point I’m happy that a positive “side effect” of getting a new wifi network is that HomeKit with Rachio now seems to work. Neat.
Dear Mr. Blasta,
I wouldn’t relax just yet - my Rachio3 now works about half the time (which is a huge improvement over this time last year when it could not be introduced to HomeKit for love nor money.)
But for the other half of the time it’s angry red icon central.
Nothing I do on my iPhone iPad or Mac makes any difference. Unplugging the Rachio and plugging it in again mostly gets it back into the HomeKit setup. Perhaps I should use a Smart plug for the Rachio, so if it isn’t responding I can turn its power off and on again using something reliable.
On just have the smart plug on a timed automation to turn off and on again at midnight and noon…
Jon.
Dear Mr. Brawn 
,
I am wondering what you’re using for WiFi network hardware, if you don’t mind?
Thing is: An iOS update should have no effect on existing Rachio 3 ↔ HomeKit connectivity whatsoever. Once an iOS/IPadOS device has been used to get things set up, it need no longer even be present for the association to remain. Please see: Apple HomeKit, iOS/iPadOS, and the Rachio 3 (And other networking notes)
Is it possible there was a coincident HomePod, or whatever you’re using for a HomeKit host, OS update, too? We don’t have any HomePods, yet, but t’s been my experience that when Apple releases a major iOS/iPadOS update, there’s often a tvOS update at the same time.
If you work in I.T., then you should be aware that if you change one thing in a network environment and network behavior changes, odds are the one thing you changed is the reason for the different behavior.
This is basic Troubleshooting 101.
You are missing the point… all other HomeKit accessories are, and have been, working fine since iOS updates and whatnot. This is simply a poor integration of HomeKit on the Rachio. Apple is aware of this as well.
Thanks,
-Dilan
I gave up on trying to fix this. *Mine just works and I hate it that others are having problems…
I keep an eye on this thread that I started 2-1/2-3 years ago and I really don’t think this is something the community can fix. It is simply up to Rachio… Life is too short to worry about these kinds of things for me.
[spot check: Today my Rachio is: ONLINE]
I’m using a mix of assorted eero hardware. I have most of the fancy features turned ON, though the HomeKit feature is in a screwed up state at the moment - eero thinks it’s on, Home app doesn’t. I’ll mess with it next time I’m feeling brave.
Jon.
Hmmm… Sensing a pattern, here 
Me too… everything in my network works all the time except my Rachio, which has intermittent HomeKit functionality.
I’m really not going to let you tell me that my Wi-Fi hardware should take the fall for Rachio’s flawed software. Eero is pretty mainstream, and at least their support people keep me up to date with my queries (enabling eero DDNS with Google Fiber before you get on your damned high horse about how there’s problems with my network). If you want to defend Rachio’s flagrant incompetence, go ahead, but you’re the fool if you do. Or in their pay.
Have it your way. It’s no skin off my nose ¯\(ツ)/¯
Hallelujah!
“The Apple team has replicated the issue on their Rachio controllers. Our teams are working together to analyze the logs. We will be meeting next week to review next steps.”
Hopefully they will share what they found as I would love to know in addition to it getting fixed.
Now that “The Apple team” has replicated the behaviour we’ve all had for months and months, hopefully this issue will be fixed once and for all.
In the meantime I’ve added my Rachio to my Hombridge server and I’m joining @Macsterguy’s “mine just works” club 
Not the ideal scenario, but it will do for now
Welcome to the Club!
Hallelujah!!!
Ok. So I’m in the functional club with 632 and UniFi non-mesh access points.
Mine worked for months, then dreaded no response in HomeKit yet fully functional in rachio app.
Was digging through this thread and tested a new UniFi feature, not sure when it showed up, and when I clicked manually add accessory in HomeKit it actually showed up in HomeKit! Entered my pin and boom!
In UniFi controller v6.2.26
Settings>wifi>Select wifi name(mine is a shared 5/2.4)>edit>advanced>Optimize IOT wifi connectivity
I turned this on for both. It reprovisioned the AP’s and instantly worked.
IF your on UniFi. Give it a try.
Glad you got it sorted-out.
Could it be your Rachio 3 <-> HomeKit connectivity went away about the same time that feature was added to your UniFi AP(s)?
BTW: I recommend against using the same SSID on both 2.4GHz and 5GHz networks. It’s been my experience band-steering usually creates more problems than it solves–particularly in multi-AP networks.
That update came out months ago so I just don’t know. None of my other HomeKit stuff has an issue so I think something finally happened like a power cycle or whatever that caused the issue to manifest.
Thanks for the feedback on the separation. I think the biggest culprit here is the fragility of the HomeKit integration on rachio with lots of contributing factors that should be non issues, but are.
Thanks for steering me into the unifi config to overcome this.
You’re welcome.
I’m trying to find out what the option actually does. Tried searching on it every which way and came up bupkis.
