topic Re: Heat not working, cool air only in Nest Thermostats

Heat not working, cool air only

Cgarcia16 — Wed, 22 Mar 2023 22:49:08 GMT

Is the wiring correct? The rectangular box is my original thermostat vs the Google nest. Only cold air has been blowing and we are freezing. Please help, anyone!

Re: Heat not working, cool air only

Cgarcia16 — Wed, 22 Mar 2023 22:49:53 GMT

For some reason the Google nest wiring pic didn’t upload.

Re: Heat not working, cool air only

Patrick_Caezza — Thu, 23 Mar 2023 05:32:33 GMT

@Cgarcia16

You have the Nest wired wrong.

Move the blue wire from the */OB terminal to the C terminal.

Re: Heat not working, cool air only

CoolingWizard — Fri, 24 Mar 2023 04:19:34 GMT

If you are not getting Heat, the problem is not the blue conductor not being in the C terminal. If your heat is not working correctly, we need to verify the configuration of your equipment; with the OB you nest might be confused and think you have a Heat Pump. Make sure you have your heating system defined properly. I assume you have a gas furnace? On your display go into settings, then turn to Equipment, and see the wires that the Nest has detected. Does it see the wire on W? If the wire is detected, we need to see if it is defied as Forced Air, Gas. @Patrick_Caezza

Ken, The AC Cooling Wizard

Re: Heat not working, cool air only

Patrick_Caezza — Fri, 24 Mar 2023 03:31:59 GMT

@CoolingWizard

The OP only has W, Y, G, R, and C wires on the original thermostat, and they have the Google Nest THermostat wired to W, Y, G, R, and */OB, which is wrong.

You don't need to get technical on a simple issue like this.

Re: Heat not working, cool air only

CoolingWizard — Fri, 24 Mar 2023 04:17:50 GMT

@Patrick_Caezza,

The Heating system would still work without the C wire but the Nest thermostat can get confused that system might be a Heat Pump for being in the O/B*. The problem and concern is that since that wire is the COMMON, if the thermostat called for heat that could create a direct short between OB and R and irreparably damage the thermostat. The good news is the Nest defaults to an O model heat pump so it has to energize the reversing valve for cooling. This is why so many inexperienced Homeowners always complain the Nest and their heat pump is blowing cold air when calling for heat..

For the record I am a professional HVAC person with nearly 30 years experience and you have zero experience and training as an HVAC technician. The best you can do is look at wires between old and new and spot an error. I try to educate consumers to make them capable of understanding how their systems are controlled and operate; I make them knowledgeable.

Ken, The AC Cooling Wizard

Re: Heat not working, cool air only

Patrick_Caezza — Fri, 24 Mar 2023 04:28:08 GMT

@CoolingWizard

You know nothing about my experience, and you never touched a Nest thermostat before May 17th, 2022.

You are providing incorrect information and need to stop.

Re: Heat not working, cool air only

CoolingWizard — Fri, 24 Mar 2023 14:22:42 GMT

@Patrick_Caezza,

You are correct in one sense; I do not know your background. Please us tell about your extensive background in the HVAC industry or perhaps about your multiple academic degrees or certificates in HVAC technology? And What specific information have I provided that is incorrect? I have forgotten more about HVAC/R technology than perhaps you will ever learn.

Ken, The AC Cooling Wizard

AS, Air Conditioning and Refrigeration Technology

BS, Electrical Engineering

BSM, Industrial Technology Management

Re: Heat not working, cool air only

Cgarcia16 — Sat, 25 Mar 2023 13:47:33 GMT

It works now thank you all!

Re: Heat not working, cool air only

Markjosephp — Thu, 30 Mar 2023 18:51:02 GMT

Hello there,

I wanted to ensure that everything was covered here.

Thanks for sharing your knowledge here, @Patrick_Caezza and @CoolingWizard.

I appreciate you posting, @Cgarcia16, I'm glad to hear it was sorted out. If there’s anything else I can help you with, please let me know. Otherwise, this thread will be locked within 24 hours.

Best,

Mark

Re: Heat not working, cool air only

Dianahemes — Fri, 31 Mar 2023 06:58:18 GMT

Commonly, your thermostat settings could be set to the “on” setting rather than the “auto” setting. Using any other settings other than “auto” may lead to cold air blowing out of your furnace since the setting instructs the system to expel any available air despite the heat settings being off

Regards,

Diana

Re: Heat not working, cool air only

Markjosephp — Wed, 05 Apr 2023 18:00:25 GMT

Hi Diana,

I appreciate you posting and sharing your input. So I will lock the thread within 24 hours unless I can help out with anything else.

Best,

Mark