Risk of missing a temperature trigger when controlling house heat

Two related help requests:

  1. My lake house has ceiling radiant heat using line voltage thermostats in each room. I was not able to find a line voltage WiFi thermostat to control temperature remotely, so I integrated RIB relays using a ZOOZ power strip to energize the relays - using SmartThings temperature monitors along with the virtual thermostat smart app to control the temperature in each room. It works quite nicely, with the exception that my family or guests can’t adjust the temperature easily (even thought I am using Action Tiles with buttons to select a temperature). Because of that, I purchased multiple new Wyze thermostats and connected EcoLink sensors (using the terminals) to send the call for heat, rather than the virtual thermostat smart app.

When setting up the virtual smart app originally, I added multiple safety limits to call for heat, or turn off heat, in case the temperature set point “trigger”from the sensor was missed - especially if a power outage occurred in the winter time . Using the Wyze smart thermostat, I loose that safety, unless I keep the virtual thermostat running.

Is there a way to check the status of a sensor at some frequent interval (4x per hour perhaps) to trigger an action if the original trigger was missed from the EcoLink sensor (as would happen during a power failure for example)?

  1. I tested using the EcoLink door / window sensor, and tilt sensor to receive the signal from the Wyze Thermostat with a ZOOZ dry contact relay in between, which works very well.

However I checked to se what happens to the sensor status in the event of losing connection with the SmartThings hub. While monitoring the sensor in the SmartThings app, I closed the sensor (read correctly as closed), unplugged the SmartThings hub, opened the sensor, and then plugged the hub back in. After the hub was back online, the sensor still read as closed in the app, rather than open as it really was. I let it set for hours and had no change. It wasn’t until I closed and open the sensor again did the status become correct. Similar to the above request for help, is there a way to recheck the sensor status and make the correction?

I’ve search online for a solution, however I could not find any information - perhaps my search terminology is not correct.

Thank you!

Most battery operated sensors in the price range that most smartthings customers would be looking for are “sleepy devices.“ That is, they are asleep much of the time in order to save battery life. They wake up every once in a while, check to see if they have exceeded the delta measurement that requires them to report, and then either report or go back to sleep. this is what allows them to have a battery life of one or two years.

However, it also means that you can’t just send them a status check question, because if they are asleep they won’t hear it.

So… Over the years some forum members have modified some DTHs for some sensors so that every time the sensor wakes up, it sends its current status. That will get things back in sync, but it can also use up a lot of battery so you have to decide if that’s worth it to you.

Here’s a thread from several years ago in which people are discussing that approach. It includes both Zigbee and Z wave devices. But as always, the first rule of home automation applies: “the model number matters.“ And of course we are on a different platform and a different app than they were, so the code they are discussing might need quite a bit of updating to work now. And some of the people in that thread have moved on to other platforms altogether. but at least it should serve as a proof of concept.

So can it be done? Yes, for some devices, but it will require custom code, and you will pay a price in terms of battery put life.

Thank you…I was concerned that was the case (or something similar), however I thought I was missing a method to request a status …your comments on battery life also makes sense.

What I have set up works flawlessly and has been more reliable than the old mechanical thermostats which have gone out on me (and unfortunately stay closed when they fail keeping the heat on in one room). Now that there is an lower cost smart thermostat (I have six heat zones / rooms), I’ll probably hardwire those thermostats to the relays to avoid issues…I was hoping to avoid the pain of running thermostat wire from all rooms, however I feel better about that reliability.

Thanks again for the information!

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Have you thought of a “watchdog timer”?

A piece of software that guards a trigger/value is available.

[Release] WatchDog Timer

Maybe that can protect your system.

Grtn Ben

Thank you! I haven’t seen this before…I will certainly check it out.