Compatibility check circled me to here

[ericS86]

Was hoping people here could help me out. I was trying to determine if I could replace a Lennox 49W95 with any Nest product. This thermostat keeps failing leaving the home with no heat randomly, which is not great in a cold climate. 

Existing wiring shows an R, i+, i-, & C terminal. 

[furqanhamid]

As per my knowledge,  Nest thermostats are usually not compatible with the i+ and i- terminals on your Lennox 49W95 system.  For this purpose, you need a Lennox iComfort thermostat which will help you in this case. This is what I can suggest about this problem!

[CoolingWizard · Accepted solution]

@ericS86 ,

Your iComfort smart air handler can also be controlled with a conventional thermostat including smart thermostats.  You will need to have a thermostat cable with 5 or 7 wire conductors. 
Do you have the confidence to rewire your equipment?

AC Cooling Wizard