Zigbee device troubleshooting

For nearly a year now, I’ve had good Zigbee reliability with ST. However, I have an issue I can’t solve now:

I had a bathroom remodeled in my house. During construction, I powered off some of my Cree Connected bulbs for a few weeks. When powered back on, two of the bulbs would no longer respond to control commands. Also, more recently, two of my ST multi sensors in the same room have stopped working. There are 4 Cree connected bulbs in the same room. Two work 100% reliably, the other two barely at all (but sometimes respond). The room they’re in is on the fringe of Zigbee range from the hub, but there are some other Cree bulbs and a Sengled bulb between the two that could (do?) act as repeaters. Here’s what I’ve tried to fix:

-Factory reset both bulbs and re-join to ST.
-Removed bulbs from ST and re-added.
-Replaced one of the bulbs with a new bulb.
-Powered down all zigbee devices that could act as routers and powered back on.
-Factory reset nearby Sengled bulb that could be a router, re-joined to ST.
-Checked/changed channel of wifi network.
-Powered off wifi AP for testing.

None of this gets those two devices to work reliably. It really seems like a Zigbee routing issue, but I don’t have any tools to troubleshoot this sort of thing. What can I try next?

Sengled bulbs are very unusual in that they do Not act as repeaters at all. This is intentional on the part of the manufacturer, who was concerned that people turning off a bulb at the switch might then lose a repeater from the network. So in terms of network planning, they are exactly the same as a battery-operated sensor. They will take up a child slot on a parent device, but they will not repeat.

In your case, it sounds like you may have run into a problem that can sometimes occur in zigbee, which is that of orphan devices that cannot find a parent because the network configuration has changed since they were first added and there are now no child slots available on a repeater near them. ( this is also sometimes called “bottlenecking”.)

You may have the same devices in the same physical locations, but because they have now been added in a different order to the network they have different parents and sometimes it’s sort of a musical chairs issue where now somebody gets left out.

This can also happen if a particular repeater goes bad and then its former children can’t find a new parent. :disappointed_relieved:

If you’ve been adding a number of new devices, you may also run into the hub’s own device limit for directly connected devices.

Unfortunately, since SmartThings does not give us any routing utilities for zigbee, this can all be very difficult to troubleshoot on your own.

My suggestion would be that you just get in touch with support and let them look at it and see if they can see anything from their side.

Otherwise you’re going to have to go through a very tedious trial and error process of removing devices and trying them in different locations and seeing if you can find a layout that works.


Thanks for the response, JD. I did just open a support case, so perhaps they will be able to pinpoint the router that’s the issue here.

Do you have any clear information about whether the Cree Connected bulbs will act as repeaters? If the Sengled does not, and the Cree bulbs do not, then I have some overall Zigbee range issues that need to be addressed. Although the behavior I’m seeing does not support that scenario–the other devices in that room–some of which are further away from the hub-- work reliably. It doesn’t seem to be purely a range issue.

Oh, also, I’ve tried powering down the hub for 20 minutes to do a “zigbee heal”.

Cree bulbs do act as repeaters, yes.

But “range” is more complicated than just measuring the distance. Each device will choose its parent based on a number of factors, including signal strength. But it doesn’t use distance because it doesn’t have any way of measuring distance. Signal strength is sort of a proxy for distance, but not exactly. You might have a close device with a strong signal but it might not have any child slots left to accept a new routing. So you can’t always predict what device will be selected as the parent.

Ok, thanks. I think my next step will be to factory reset the remainder of my Cree bulbs. Can’t hurt.

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Okay, some new info:

I just factory reset every Zigbee device I have that’s AC powered. One 2016 SmartPower outlet, 9 Cree bulbs, and the Sengled bulb. The only two that I had any issues with during this process were the two at issue here: one bedside light and one closet light, both Cree bulbs. So after a bunch more random troubleshooting, I found that the two troublesome bulbs will work if they’re moved to the other side of the room, which has a more direct line of sight to the hub. But they stop working when moved back to their intended locations. I find this very strange, since there are other reliable Cree bulbs mere feet from these two troublesome ones. But alas, it appears that these two are in an RF dead zone. I also suspect that these were working fine before, albeit marginally (I guess), and moving some walls around in a nearby room during the remodel changed the RF characteristics of the house just enough to ruin the path to these two bulbs.

So, my question now: there is a very good chain of Cree bulbs all the way back to my hub from the bedroom where all this trouble is happening. Why are they not repeating Zigbee messages? The only odd thing I have going on here is that I changed the Cree DTH to the “SmartPower Dimming Outlet” DTH to get local processing for these devices. Although I assume that has no effect on their inherent Zigbee routing behavior.

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Ok, now, given the above, I’ve reintroduced a newer SmartPower outlet that I usually only use during the holidays to act as a repeater. Almost immediately after plugging it in (centrally located in the house), the two problematic bulbs started working again.

My conclusions here are:

-This was a RF coverage issue all along
-My Cree Connected bulbs are not acting as Zigbee repeaters for themselves or other ZHA devices.

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