During the day my thermostat is on heat and it blows out cold air does anyone know why

[Smith1304]

during the day my thermostat is on heat, but it blows out cold air. At night it’s on heat and heat blows out. Does anyone know how to fix this?

[Houptee]

What kind of system do you have?

Gas heat? Heat Pump with AC? OIl?

No way to know you do not provide any info.

How long has the Nest been working before this problem?

[Smith1304]

Heat pump AC and it just starting doing it a few days ago

[Smith1304]

 

[Houptee]

Looks like a Natural gas furnace not a heat pump, unless you have a heat pump and the gas furnace is backup heat.

Heat pump is a AC system that runs the outdoor unit in winter in reverse to heat the house.

Did you install the Nest yourself?

Can you pull the Nest off the base and take pic of the wires connected.

This is a strange problem if it works at night normally but not in the day.

[Smith1304]

Yes I installed it.

[Smith1304]

It won’t let me upload a pic again for some reason I will try again in the morning

[Smith1304]

 

 

[Houptee]

Looks correct wiring.

Only thing you can do is use a multimeter set for AC volts. When its not turning on the heat go to the furnace and test for 24 Volts AC by putting the meter red lead on the White wire and the meter black lead on the C wire on the furnace.

The Nest sends 24 volts out the White wire when it wants heat to turn on.

If you have 24 volts on white wire at furnace the fan and the gas burner should both be on.

If you have a main control board in the furnace they usually have a LED that blinks fault codes and there is a decal on the door that explains what the flashing LED codes mean.

If you do not have any 24 volts but nest is asking for heat then maybe a loose White wire at the Nest or on the furnace or a break in the wire somewhere.

[Smith1304]

If I change the heat to 75 to 76 it says house with heat in 30 min then it starts blowing the cold air

[Houptee]

Try removing the white wire at the Nest and use pliers to make the wire straight and insert it again into the Nest connector. In the pic white wire looks kind of bent maybe it's not making a good electrical connection.

If no result the only thing left to do is test with a mutimeter at the furnace for power arriving on the white wire when the Nest is lit up orange and asking for the heat to turn on.

If you have power 24 v on white but heat is not kicking on then it could be a problem with the furnace and like I said look for the LED blinking a fault code on the furnace control board.

[Smith1304]

Thank you for your help I will try that today.

[Jhonleanmel]

Hey folks, 

We appreciate your help here, @Smith1304.
@Houptee, 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 concerns or questions from here, as I would be happy to take a closer look and assist you further.

Thanks,
Mel

[Dan_A]

Hey there,

I'm chiming in to ensure you've got the answer you're looking for. Feel free to let us know if you have more questions about this.

Regards,

Dan

[Dan_A]

Hi folks,

We haven't heard from you in a while so we'll be locking this thread if there is no update within 24 hours. If you need assistance or want to discuss topics, feel free to start a new thread.

Best,

Dan