My Nest thermostat does not turn on the furnace

[mrbing]

My Nest thermostat is fully connected to my Google home, all the wires are inserted properly (C,W &R) but it still does not turn my heater on.  I am out of ideas on what is wrong with this.

[Houptee]

You can test if its the Nest or the furnace by pulling the Nest and use small piece of wire and insert it into the holes on the terminals connecting R to W. This should kick on the heat if you hold those two connected with a jumper wire. If it doesn't work then you have a problem with the furnace.

Some furnaces have a fuse on the main board like a plug in car fuse you can go check that see if you have blown fuse or blinking led on the furnace board showing error codes. There is a decal on the back of the cover that tells you what the flashing led means.

[Ksenijakh]

I have the same exact problem, everything is connected correctly yet when I do the test run nothing turns on. If I put my old thermostat on, it works just fine. Go figure! 

[Houptee]

Post pics of the nest wiring so we can try and help.

And what kind of system do you have? Hot water boiler heat or hot air furnace? Heat pump etc.

[Houptee]

Also post pics of old tstat wires and nest wiring.

What kind of heater is this? A gas hot air furnace or a boiler for hot water heat?

If you can take a pic of the furnace thermostat wires connections and the make and model number that might help.

[Ksenijakh]

Unfortunately I did not take the nest photo wiring. I have a gas furnace with a/c 

I do have a C wire, it wasn’t used for the Honeywell thermostat, and I did not connected it to Nest because when the C wire was connected the Nest wouldn’t power on. If that makes any sense. 

[Houptee]

That is strange the C wire must not be connected to the C screw on the furnace board. You would have to go take the front cover off the furnace and look at the wires and check if it is connected to C (or B if a Trane).

[Ksenijakh]

 

[Houptee]

Do you have the Learning Nest or the regular Nest with mirror glass?

Looks like basic R to R, G to G, Y to Y, W to W

But the regular Nest usually needs a C wire to get stable voltage to keep it powered up so I would go to the furnace take off front panel and see where the C wire you mentioned is connected at the furnace screw terminals. Hook it up to C screw and then hook it up at the Nest to C.

[Ksenijakh]

Thanks for helping us. 

I have a learning Nest. 

[mrbing]

I am using this on  a gas furnace with an R and W wire.  I also have the Nest Power Connector because I do not have the C wire.  All 3 wires are connected to the right connector on the thermostat.  Using the old thermostat the heater will work. I have reset the thermostat to factory settings and re-installed it but no luck on getting it to heat the house.

[Houptee]

Do you have a picture of the wires at the furnace to confirm you hooked up the power connector properly.

[mrbing]

I confirmed the R and W by testing with the multimeter on each end.

 

[Houptee]

Where is the Nest power connector, the white device hooked up?

It needs to be wired to the furnace correctly I don't see it in your pics.

It needs to be connected so the 3 wires RWC go to the C screw at the furnace transformer and the R W screws on the furnace,  Then you connect the 2 wires that are on the furnace in your pic to the 2 wires on the connector R W.  Then at the Nest only the R and W get connected (you wont have a C wire at the Nest).

[mrbing]

I only have 2 wires coming from the furnace R & W.  Since I have the regular Nest Thermostat I ordered the Nest Power Connector and have it connected so that I can have the C wire.  

 

 

  

[Houptee]

No you hooked up the power connector wrong.

It does NOT hook to the Nest thermostat base.

It installs at the Furnace end of the wiring.

You have to have a real C common terminal at the furnace and hook the C wire to it.

Watch this video.

https://youtu.be/xlx2Um6D1Z8

[mrbing]

I have an older furnace that uses a 24volt transformer and that is where the two wires originate from and the R&W are the only two connections that go to the old thermostat.  I bypassed the Google Power connector and the heater turns now turns on.  What is the downside of not using the power connector?

[Houptee]

There is a common side of the 24v transformer on the furnace.

You have to locate the transformer, there are 2 wires that leave the transformer, one goes directly to the little red panel "R screw" that is the + R side of the transformer, the other wire coming off the transformer will be the C - common side.

You might have to tap into the common wire with a wire nut or similar method since there is no screw for it.

Then the power device will go to the C and then remove the 2 wires from the red panel screws and put R W from power device to those screws.

Then the old thermostat wire that was on the 2 screws splice to the power connector R W wires.

[EdwardT]

Hi folks,

@Houptee, thanks for the help!

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

Thanks,

Edward

[Ksenijakh]

I’ve tried everything and at this point I will have to pay a professional to come and do it, which to change a thermostat seems like a big investment. In the end I’ll just return the product. Thanks for following up. 

[EdwardT]

Hi Ksenijakh,

Thanks for the response. Please let us know once a tech checked your system. Keep us posted.

Thanks,

Edward

[EdwardT]

Hi Ksenijakh,

I wanted to follow up and see if you are still in need of any help. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further.

Thanks,

Edward

[EdwardT]

Hi Ksenijakh,

I'm just checking in to make sure that you've seen our response. Please let us know if you have any other questions or concerns as I will be locking this in 24 hours.

Thanks,

Edward

[Ksenijakh]

I did not have any luck with it so I returned the product. 
thanks for checking in. 

[EdwardT]

Hi Ksenijakh,

Thanks for the response. We're sad to see you go. We hope we can make it up to you in the future. Let me know if there's anything else.

Thanks,

Edward

[Jake]

Hey there,

I wanted to check in, and let you know that I will be locking the thread in 24 hours.

Best regards,

Jake