How to detect unreachable Z-Wave device or node?

Friends,
I have a new Zooz ZEN20 power strip that is Z-Wave plus, and it works very well with HA - but I’m having trouble detecting when the device is unreachable. I have it unplugged right now and it is completely dead yet the status in HA shows “Ready”. For what I need to accomplish I must be able to detect when the device is unreachable because what it’s powering is somewhat critical (aquarium sump return pump) and while I can alarm on the switch being turned off, it never detects that anything is wrong if the darn thing is just down or unplugged completely. I’ve attached a screen shot of the device entity and that’s after it’s been unplugged for several minutes. Any ideas here?

I found that trying to send a signal to the device twice caused it to realize it had gone unreachable, marking it as failed. So I found an insignificant port to send a command to every minute to make it detect within 2 minutes or so.