![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
![heating - Wifi thermostat to replace old mechanical 2-wire 110V Honeywell? - Home Improvement Stack Exchange heating - Wifi thermostat to replace old mechanical 2-wire 110V Honeywell? - Home Improvement Stack Exchange](https://i.stack.imgur.com/YnlT0.jpg)
heating - Wifi thermostat to replace old mechanical 2-wire 110V Honeywell? - Home Improvement Stack Exchange
![My heat-only system only has two or three wires connected to the thermostat. Am I compatible with ecobee? My heat-only system only has two or three wires connected to the thermostat. Am I compatible with ecobee?](https://storage.googleapis.com/article_attachments/227874667/Untitled_Diagram__10_.png)
My heat-only system only has two or three wires connected to the thermostat. Am I compatible with ecobee?
![Photo Guide to Installing a Nest Thermostat - How install, wire, adjust, program or repair Nest thermostats Photo Guide to Installing a Nest Thermostat - How install, wire, adjust, program or repair Nest thermostats](https://inspectapedia.com/heat/Nest_3_Installation_342_DJFs.jpg)
Photo Guide to Installing a Nest Thermostat - How install, wire, adjust, program or repair Nest thermostats
![2-Wire heat only furnace for Nest E. The Nest is having problems staying powered. Can I use an external 24V power supply? How would I route the additional wires? https://www.amazon.com/dp/B07FT2RCG9/ref=tsm_1_tp_tc : r/ Nest 2-Wire heat only furnace for Nest E. The Nest is having problems staying powered. Can I use an external 24V power supply? How would I route the additional wires? https://www.amazon.com/dp/B07FT2RCG9/ref=tsm_1_tp_tc : r/ Nest](https://preview.redd.it/sh6zbm6409h61.jpg?auto=webp&s=3620f2cb24653051517a60e200a76456b90dea7e)
2-Wire heat only furnace for Nest E. The Nest is having problems staying powered. Can I use an external 24V power supply? How would I route the additional wires? https://www.amazon.com/dp/B07FT2RCG9/ref=tsm_1_tp_tc : r/ Nest
![My heat-only system only has two or three wires connected to the thermostat. Am I compatible with ecobee? My heat-only system only has two or three wires connected to the thermostat. Am I compatible with ecobee?](https://storage.googleapis.com/article_attachments/227874667/gasvalvefaststat.png)