Thermostat E no power on R

[hkhattri]

Hello, I’m getting an error “no power on r”. Having read a bunch of docs I think I don’t need to wire in c; nest should work on battery (which is up to 3.9 volts). However I still get no power. 

What am I missing?

thanks

[CoolingWizard]

@hkhattri The Nest Learning Thermostats can detect the presence of the wire inserted in the R terminal.  It then checks this wire for power by internally connecting to Y, G, and/or W to see it creates a current load. If it does not it reports the error of no power on R.  Make sure your R wire was stripped to the proper length and is fully inserted.

AC Cooling Wizard 

[hkhattri]

Thanks so much for the quick response. Yes, the R wire is connected properly. In fact it’s been working for a few years. 

anything else I can check?

[hkhattri]

Would be great if there is anything else I can try. Thanks in advance 

[CoolingWizard]

@hkhattri ,

if you have a digital or analog volt on multimeter, you can use it to verify that the air handler transformer is outputting the proper 24 V AC power. It’s possible that the transformers gone bad or that the fuse supplying the power has tripped inside the control board. 

AC Cooling Wizard

[hkhattri]

Thank you @CoolingWizard