DIY fixed temperature alarm

I hadn’t seen anyone else post this here.

I created my own low temperature alarm for my home for when I am away. Using a KSD 9700 15°C bimetal thermal protector and a contact sensor module. I picked up a few from eBay for a couple bucks each. The protector switch closes on temp drop at approx 10°C and opens on temp rise at approx 15°C. If my furnace fails during cold weather I will receive a notification if my house gets too cold. I also connected the contact sensor module to two AA batteries so I don’t have to worry about the battery failing and won’t need to buy anymore of those expensive watch batteries.


I doubt that anyone else tried this or is interested, but thought I would add this info.

Seems that the KSD 9700 15°C bimetal thermal protectors are not very reliable. After several cycles I found that the KSD 9700 fails completely and will no longer reset/open correctly. When I replaced the one that failed, I found that a couple of the other KSD 9700 were not very accurate. Probably better off to purchase an inexpensive thermostat to use in place of the thermal protector.

Thanks for the update.