Lost two Osram bulbs (zigbee) and one ST Multi Sensor (zigbee) and recovered them - new feature?!

So this morning I found out that my two outdoor Osram RGBW lights went silent (they turn colors when turned on - a sign that they do not belong to any network) and one of my ST-branded multi sensors also went quiet.


  • for the bulbs, both of them go in a color sequence when turned on - this means they do not belong to any network and are ready to join one.
  • for the sensor, I found the battery was weak (faint blue light during zigbee communications) - replaced the battery, no dice. Much better, brighter blue light during communication, but still nothing in the ST app. Sensor occasionally blinks 3 times - I think that means the same, ready to join a network.

How I fixed it - and am surprised:

While I was walking around with the ST multisensor in my hand, I went into the ST app and went to add a new Thing. Clicked Connect now… and all of a sudden I see a green solid light on the sensor. I go back to the device and find it reporting as if nothing happened. Woaaaahhhhh… I then went to the lights, turned them off, back on, acknowledged their red/blue/yellow/green/white cycle, then tapped on Connect now again… what do you know, both lights are back in. I can control them as if nothing happened. Apps work just as they used to, looks like joining a device that has been previously joined will simply fix the link that used to exist between that device and the hub.

Is this a new feature? Was this the case before? Remember, I did not remove any device, I did not replace any device (that option is only available for zwave anyways), I did not delete any device from any SmartApp, all I did was just to look for new devices, as if I am adding one to my setup. Oh and the search yielded nothing - there was absolutely no finding in the ST app - no warning of any sort, no message, no anything. Just the blue and white rotating circle as it searches devices… it found no device, but it fixed the three…

Not new feature. Your devices have been kicked out. That’s the flexibility of zigbee, they reattach easily.

Replace is a function of zwave to compensate for its inflexibility -)


So this is how it’s intended to be? Cool, on to more zigbee devices then :wink:

Well, it comes with a price. I find zigbee more fragile and more susceptible to drops and interference.

I assume zigbee can do this because the device itself contains a zigbee id and the hub uses that as a unique identifier for the link, whereas with zwave, the hub determines the id at join time. So it would not be able to tell if the same device was already connected… it would simply readd the same device with a newer, higher id. Right?


I find this to be the case for some of the z-wave as well. Instead of remove I just exclude the device and add it back. Doesn’t work for all zwave unfortunately.

I find that ever since the hub update on 8/15, four or five of my various Zigbee devices have dropped off the network and I have added them back as you described. Problem is that lately, these devices keep dropping off every 6-12 hours and I have to go through the whole rinse, lather, rinse, repeat motions again. It’s been really frustrating. Anyone else experiencing this?

If you add back a zwave device in this manner, the hub should assign it a brand-new network ID, which then requires that you update all of your smart apps and routines. That’s exactly why the “Z wave replace” utility exists – – it allows you to reuse a previous network ID with a new device.

Zigbee works very differently. Each device has its own unique ID, and at the time that it joins the network it tells the hub what that ID is and that then becomes its network ID. That’s why you can just rediscover a zigbee device and since it will tell the hub the same device ID as the last time, it just slides back into place and you don’t have to update any code.

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And that’s how orphans are created. And when they act up, they take down your whole mesh. It might be faster but …not in the long run.