Nest gen 3 Learning T'stat wiring problems

[FredOz]

Just bought Learning T'stat.   System compatibility page says system is compatible.  Replacing older cheaper Nest which worked.  No display on Nest.  What's wrong?

Connected C to C, R to Rh, G to G, Y to Y1, W1 to W1.  Voltmeter shows -2.2V dc between R & C wires (yes negative).  

[FredOz · Accepted solution]

Correct.  It was the 5A fuse.  I'd turned off the "air handler" breaker but the furnace was connected to a different circuit.  Apparently the red wire contacted the ground while I was feeding the wires through the hole in the t'stat.

I got the Nest working, including a remote temperature sensor although Google's instructions are not the best.

[Patrick_Caezza]

It sounds like the 5amp fuse on the control board in the furnace/air handler might be blown.

[FredOz · Accepted solution]

Correct.  It was the 5A fuse.  I'd turned off the "air handler" breaker but the furnace was connected to a different circuit.  Apparently the red wire contacted the ground while I was feeding the wires through the hole in the t'stat.

I got the Nest working, including a remote temperature sensor although Google's instructions are not the best.

[Ryan_G]

Hey FredOz,

Thanks for the update and it's great to hear that you were able to get your thermostat working.

Though this has a solution, we'll observe your thermostat behavior for the next 3 days and let us know how it goes by replying to this thread.

Thanks for your help, Patrick_Caezza.

Best regards,

Ryan

[FredOz · Accepted solution]

T'stat seems to be working.  Temp. is controlled by the remote sensor and temp. displayed on the unit is from remote sensor, which is what I want to do.   T'stat is in a hallway that often has a different temp. than our living space.

Thanks,

Fred

[Ryan_G]

Hi FredOz,

Thanks for the update and it's great to hear that it is up and running fine now.

As this seems to be resolved, this thread will now be closed. If you have any other concerns, let us know by creating a new thread.

Best regards,

Ryan