thermostats in parallel

quack24

was wondering if this would work
put a regular thermostat and this one https://jacksonsystems.com/product/55-degree-temporary-heating-construction-thermostat/ in parallel with each other to protect the building from freezing in case someone shuts the heat

pecmsg

If they shut off the heat how will it work?

ethicalpaul

If by "shuts the heat" you mean they turn down or off the main thermostat, then yes that would work. If they kill the power to the HVAC, as @pecmsg indicates, that won't work.

Motorapido

I use two thermostats, in parallel. The primary thermostat is a Honeywell Lyric wifi thermostat. I like the daily usage data and the ability to change the temperature remotely, from my phone. However, I live deep in the woods, where power outages are frequent, and despite having a whole-house generator, I still wanted an additional backup to make sure my pipes don't freeze. My heat source uses a millivolt gas valve, which functions without any external power, so it works during power outages. The millivolt thermostat that I connected in parallel with the wifi thermostat is a low-temperature model, going down to 40 degrees. I keep the millivolt thermostat set to 50. That way, if power goes out and my automatic whole-house generator fails to turn on, the no-power-needed millivolt thermostat ensures that the temperature won't fall below 50.
The product in your link appears that it would work in the same method as any thermostat, so I don't see why you can't wire it in parallel with your primary thermostat to guarantee that the temperature will never fall below 50.

quack24

thanks all
when i said shuts the heat i meant turns it off from the thermostat

searay26

https://forum.heatinghelp.com/discussion/comment/1732916#Comment_1732916

This is exactly what I want to do at my cottage. For the same reasons but I don't have a back-up generator there. I installed a new battery only thermostat, just a 2 wire that controls the gas fireplace. I believe it works without power, (except for the fan) I also have a Honeywell wi-fi thermostat, along with a 24 vac transformer that I plan to use to power it. Thinking of wiring them in parallel and setting the battery operated thermostat at 50, while using the wi-fi to check temperature and change set point before arriving. I'm not good at wiring and was wondering how it was that you set up yours.