![Old Honeywell mercury thermostat Compatible with Nest learning thermostat or Nest 2020 thermostat? : r/Nest Old Honeywell mercury thermostat Compatible with Nest learning thermostat or Nest 2020 thermostat? : r/Nest](https://preview.redd.it/hedembhvkbd61.jpg?auto=webp&s=ee363b2d543dd93148e7f25277c4c89257d25fe4)
Old Honeywell mercury thermostat Compatible with Nest learning thermostat or Nest 2020 thermostat? : r/Nest
![thermostat - Honeywell Mercury Themostat 3 Wire, replace with Digital/ Programmable? - Home Improvement Stack Exchange thermostat - Honeywell Mercury Themostat 3 Wire, replace with Digital/ Programmable? - Home Improvement Stack Exchange](https://i.stack.imgur.com/oHdJu.jpg)
thermostat - Honeywell Mercury Themostat 3 Wire, replace with Digital/ Programmable? - Home Improvement Stack Exchange
Why would a new non-programmable thermostat behave differently than the old mercury one that was replaced? The new one only runs the furnace for 5 minutes before shut off. Barely makes it
![Dual Controls on Old Unit - Can I replace with programmable thermostat? - DoItYourself.com Community Forums Dual Controls on Old Unit - Can I replace with programmable thermostat? - DoItYourself.com Community Forums](https://www.doityourself.com/forum/attachments/thermostatic-controls/26728d1392399747-dual-controls-old-unit-can-i-replace-programmable-thermostat-hvac-thermostat-mercury-environment-recycle-440.jpg)