If by “don’t work” you mean you can’t get them to join to the network, that’s an entirely different kind of issue.
Smartthings should be able to “find” any certified zwave device.
It was zwavewave device can’t be found, the problem is almost always one of two things. Either the device is using a different Z wave frequency and the smart things hub, or the device thinks it’s still belongs to a different network this can happen even with a brand-new device because devices may have been paired with a test network at the factory, and then for one reason or another, this information was not cleared prior to shipping.
If the device is on a different frequency, there’s nothing you can do. The two devices will not be able to talk to each other.
However, if the problem is just that the device still thinks it belongs to a different network, that’s easy to fix by first clearing the information about the old controller from the device.
When this happens, any Zwave controller, including the SmartThings hub, can do a “general exclusion.” You will have to do something physically with the & device, typically push a button on it, which puts it into listening mode.
Then you have the smartthings hub send the general exclusion command, which tells any Z wave device nearby that is listening that it is OK to clear the controller information if it is trying to do that.
At that point, the device you pushed the button on should clear its old controller information. Once that is done, it is ready to join a new network.
So now you follow the procedure for that device to join a new network.
Support can help you with this if you have trouble joining any individual device to a network.
http://support-uk.smartthings.com/hc/en-gb/articles/204656422-How-to-Exclude-Z-Wave-Devices