topic Re: My Nest thermostat does not turn on the furnace in Nest Thermostats

My Nest thermostat does not turn on the furnace

mrbing — Fri, 20 Jan 2023 23:47:53 GMT

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.

Re: My Nest thermostat does not turn on the furnace

Houptee — Sat, 21 Jan 2023 00:07:59 GMT

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.

Re: My Nest thermostat does not turn on the furnace

Ksenijakh — Sat, 21 Jan 2023 00:45:42 GMT

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!

Re: My Nest thermostat does not turn on the furnace

Houptee — Sat, 21 Jan 2023 00:53:16 GMT

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.

Re: My Nest thermostat does not turn on the furnace

Houptee — Sat, 21 Jan 2023 00:57:27 GMT

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.

Re: My Nest thermostat does not turn on the furnace

Ksenijakh — Sat, 21 Jan 2023 01:00:37 GMT

Re: My Nest thermostat does not turn on the furnace

Ksenijakh — Sat, 21 Jan 2023 01:03:44 GMT

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.

Re: My Nest thermostat does not turn on the furnace

Houptee — Sat, 21 Jan 2023 01:25:23 GMT

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).

Re: My Nest thermostat does not turn on the furnace

mrbing — Sat, 21 Jan 2023 01:56:38 GMT

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.

Re: My Nest thermostat does not turn on the furnace

Houptee — Sat, 21 Jan 2023 04:16:47 GMT

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

Re: My Nest thermostat does not turn on the furnace

mrbing — Sat, 21 Jan 2023 04:47:32 GMT

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

Re: My Nest thermostat does not turn on the furnace

Houptee — Sat, 21 Jan 2023 05:34:06 GMT

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).

Re: My Nest thermostat does not turn on the furnace

Houptee — Sat, 21 Jan 2023 05:42:09 GMT

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.

Re: My Nest thermostat does not turn on the furnace

mrbing — Sat, 21 Jan 2023 05:54:04 GMT

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.

Re: My Nest thermostat does not turn on the furnace

Ksenijakh — Sat, 21 Jan 2023 14:54:46 GMT

Thanks for helping us.

I have a learning Nest.

Re: My Nest thermostat does not turn on the furnace

Houptee — Sat, 21 Jan 2023 15:17:58 GMT

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

Re: My Nest thermostat does not turn on the furnace

mrbing — Sat, 21 Jan 2023 17:30:03 GMT

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?

Re: My Nest thermostat does not turn on the furnace

Houptee — Sat, 21 Jan 2023 19:54:17 GMT

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.

Re: My Nest thermostat does not turn on the furnace

EdwardT — Wed, 25 Jan 2023 02:37:35 GMT

Hi folks,

@Houptee, thanks for the help!

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

Thanks,

Edward

Re: My Nest thermostat does not turn on the furnace

Ksenijakh — Thu, 26 Jan 2023 14:55:22 GMT

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.