I don’t have much experience with Zigbee but have gotten the impression that it can be temperamental in certain situations involving interference. I had my little network working well for about a year and a half before it started being unreliable and no suggested changes helped. Figured this was worth sharing.
Short version: A bad PC power supply was apparently the cause, and there was no good way to discover this until it totally failed.
Long version: So far I have very simple Zigbee needs. 3 thermostats and 1 light bulb to play around with. I had this working well for a year and change with just those devices and a Conbee II stick, using ZHA. About a year and a half ago now, things got weird. The light would only respond occasionally as would the thermostats. They would always update their status to HA if manipulated manually, but I was having a lot of trouble controlling them from HA. Annoying, as I have automations running my HVAC schedule.
I’m not in a crowded area, but still figured something had changed just enough RF-wise to start causing issues. So I upgraded to a Sonoff dongle w/antenna, away from the HA machine via USB extension. This helped a little bit, but not enough. I could sometimes get things to behave for a little while by power cycling the thermostats or doing a radio migration/reconfiguration via ZHA. But it would always go back to basically not working.
Around the same time a Zigbee got weird, the GFCI breaker for my utility room where HA lives would occasionally trip. There’s a lot of stuff on that circuit (all the network gear, a bathroom, sump pump, etc) so I did not correlate the 2 problems at all. It wouldn’t trip often, maybe 6-7 times over the past 1.5 years.
Two days ago I hear the breaker click off, the UPS start squealing and the internet goes out. I go down there and everything on the battery side of the UPS is off (HA and all the network stuff) and it’s showing an error code. Hmmmmm. So I reset the breaker, watch the network stuff start up, then I hit the power button on the HA box. The breaker trips and the UPS starts freaking out again. I do this one more time just to be sure; same results.
I bring the HA box upstairs, plug it into a GFCI outlet in the kitchen and hit the power button. This time the GFCI doesn’t trip but the power supply makes some very sad noises then goes silent. I then stick another power supply in the machine and boom, it’s happy again. It’s been running since then and every time I make the thermostats do something via HA, they respond instantly like they used to.
The HA box was otherwise running fine this whole time. The only oddity I noticed was the CPU fan on full blast all the time. That has also reverted to idling unless things get warm.
So there you go, one “never would have guessed” thing making Zigbee suck.