In the 80s and 90s, thermostats had physical dials and mechanical temperature metres that did not require power. They only had two terminals for sending a signal to the controller of the furnace.
This is one. They were everywhere until the mid to late 2000s.
How old are you?
In the 80s and 90s, thermostats had physical dials and mechanical temperature metres that did not require power. They only had two terminals for sending a signal to the controller of the furnace.
This is one. They were everywhere until the mid to late 2000s.
https://www.ebay.com/itm/168792921855?_skw=vintage+thermostats&itmmeta=01M514T246XJDF5H4WFN95E4RC&itmprp=enc%3AAQALAAAA8LMoA3ATICNpdlejoNWn7EezK5ZxAKW7tSATJgJx%2F6H0mD4oKHO1pSLMuM11igxCTPC1IUSE6bMW%2F8SYPHbRWdMjO4hY8Mlc4gX1Bk0TN9KJLNzmKRf32UREURMJwMgwoHapUGrCtpVJNXQDg%2BxS%2Blvqt2JzwANzqAclKOChcGTvtVA%2FN7YP22xreS5NtMmfzEMzE6OQnzhRQgG9b%2FQll4Uezp5J%2BX7zTKprWaj%2Bk6MhdkuM2590Cz6zryT7ZdSA2XWtzJLbx1W5E7WVhd5LKb9jvo2txTWAQyEGA7d5Eg8mZSVmML3%2FVW%2FmpWxoZyvRMQ%3D%3D|tkp%3ABk9SR7Si6KSoaA