Using Old Thermostat on Modern Furnace

[tanker]

My plumber just installed a new furnace and I would love to be able to use my still working mercury bulb thermostat. Prior to this I had a 60 year old furnace all mechanical. My new furnace is basically a computer. Would the two not be able to work together. I don't see why not.

 

[tanker]

Just got off the phone with my electrician. The "Nest" and the "Honeywell Lyric" are my only supposed two options for my furnace. I was told it had something to do with the older thermometers not having enough power to control the modern computer system. I do not care for the cost or controls of a smart thermostat and would love a manual thermostat. I am aware Honeywell sells a modern Mercury free thermostat with the old fashioned controls (Honeywell CT87N1001). Might that work?

 

 

[tanker]

The name of the furnace or really should say boiler is the Weil-McLain GV90+. It's Gas-Fired.

 

[RAL]

According to the installation manual, this boiler requires just a 2-wire thermostat.  So your old thermostat should work just fine.