Nest thermostat connected over 3 years red wire not connected?

[Robin66]

Nest thermostat has been connected and used over 3 years.

Now there's an error 

7 times this happened in 3 months  showing diagram and error says red wire not connected yet it is. No one has been messing with it,  the thermostat.  I turned off the power to the whole house. Had to wait and hour and boot everything back up. Sufferings this helps sometimes I have to wait 3 hours to reset. Why is this happening? Sometimes the air handler keeps ribbing with no air. It it time to upgrade my best thermostat? Do they get old? What about the batteries inside for memory?

[Houptee · Accepted solution]

Check the wires at the system end and confirm they are all tight on the furnace or air handler terminal strip screws.

If you get the error again use a multimeter set to AC volts and test at the system wires R and C for 24v AC.

If no voltage at the system terminal strip then its a problem with the transformer inside your system not producing 24v.

[EdwardT]

Hi folks,

@Houptee, thanks for the help!

@Robin66, how's it going with your Nest Thermostat? Still need our help?

Thanks,

Edward

[Jeran]

Hey there Robin66,

Did you have any more questions or need any additional help? 

Thank you,
Jeran
 

[Jeran]

Hey Robin66,

Did you have any more questions or need any additional help? If not, I'll go ahead and lock up this thread in 24 hours.

Just checking up,
Jeran