![Two 2 wire Honeywell digital thermostat to replace mercury switch. Convert from mercury switch - YouTube Two 2 wire Honeywell digital thermostat to replace mercury switch. Convert from mercury switch - YouTube](https://i.ytimg.com/vi/YqTUSs56E7A/maxresdefault.jpg)
Two 2 wire Honeywell digital thermostat to replace mercury switch. Convert from mercury switch - YouTube
![electrical - Old oil furnace with 2 wire thermostat, installing new wifi and need C wire. How can I wire with my current stack switch? - Home Improvement Stack Exchange electrical - Old oil furnace with 2 wire thermostat, installing new wifi and need C wire. How can I wire with my current stack switch? - Home Improvement Stack Exchange](https://i.stack.imgur.com/Hq7vG.jpg)
electrical - Old oil furnace with 2 wire thermostat, installing new wifi and need C wire. How can I wire with my current stack switch? - Home Improvement Stack Exchange
![Trying to replace this old 2 wire thermostat for a newer digital one. Problem is older unit does not have leads labeled or which cable is which. Any help on how to Trying to replace this old 2 wire thermostat for a newer digital one. Problem is older unit does not have leads labeled or which cable is which. Any help on how to](https://i.redd.it/j9mnonzn7nu91.jpg)
Trying to replace this old 2 wire thermostat for a newer digital one. Problem is older unit does not have leads labeled or which cable is which. Any help on how to
![Old Honeywell 2 wire AC thermostat (with 1 extra wire behind) - can I modernize this with Ecobee? : r/ecobee Old Honeywell 2 wire AC thermostat (with 1 extra wire behind) - can I modernize this with Ecobee? : r/ecobee](https://i.redd.it/old-honeywell-2-wire-ac-thermostat-with-1-extra-wire-behind-v0-zgb7bnf4hv2b1.jpg?width=3024&format=pjpg&auto=webp&s=260717dc10e09aa7edef141b700365ef3292e75f)