Switching over from Ecobee to Nest 3rd gen

[Andrew0013]

Hello,

Switch over from Ecobee to Nest 3rd generation has not gone well.  Ecobee had C, RH jumped with RC, G, white wire jumped W O/B and Y.  

I matched the system over and now the ac turns on with heat.

I then looked at the control box in the furnace to find black as C, red is RH jumped with RC, white jumped with W and Y, green as G.

Of all the forums I cannot find an answer but some people with similar problem of ac and heat together. The solution of changing heat source to gas does not solve the issue. I made sure the thermostat was in heat only mode.  As of right now I just flipped the ac breaker to make sure they don't run together.

Any ideas?

[aperezdeleon]

Hiya Andrew0013,

Thanks for posting to our community.

Transitioning from your old thermostat wiring configuration to the Nest thermostat can be confusing, especially if your system has some unique wiring features. That might be the case here!

There's a possibility that in your previous thermostat, the white wire served a dual purpose, controlling both heating and cooling.
Since you matched your wiring exactly, the Nest thermostat might not be able to control heating properly.

Because some of your wires seem to have multiple functions, I recommend contacting a technician. They can see if your system can be wired in a way that allows the Nest thermostat to control heating with independent wires.

Please keep me posted.

Regards,
Angel.