10-02-2023 12:55 PM
I’ve had my thermostat for a while and have used it for cooling only. Today I decided to test the heat and it’s blowing cold air and dropping the temperature. Please help!
10-02-2023 12:57 PM
my original wiring
10-02-2023 12:58 PM
My current wiring. I have tried switching the heat pump from O to B and they both cool
10-05-2023 01:30 PM
Hi Socalgirl415,
Oh no! Sorry to hear that — let me take a look at this for you.
Turn off the power to your thermostat, and instead of connecting the blue wire to the OB terminal of your Nest Learning Thermostat, connect it to the C terminal instead. Update your thermostat wires on the thermostat itself, then check again if heating will work.
Let us know how it goes.
Best,
Zoe
10-30-2023 05:43 PM
That didn’t work. It gave me an E78 error
10-31-2023 10:16 AM
Hi folks,
@Socalgirl415, thanks for keeping us in the loop. Please provide your Nest Thermostat's power readings under technical Info. Also, please check your system's power.
First, make sure the power to your system is on. The power switch will usually be in your breaker box or fuse box, but in some homes it will look like a light switch near the heating or cooling equipment.
Next, check that your system's wires are in the right connectors.
I appreciate the input, Zoe.
Kind regards,
Jenelyn
11-20-2023 09:26 PM
It’s shows no power when I switch the blue wire to the C slot from the O/B slot. I can’t get the heater to work on the thermostat but if I switch to my old thermostat the heater works fine.
11-20-2023 09:27 PM
11-21-2023 07:55 AM
Hi there Socalgirl415,
Thanks for providing the additional information above. To confirm, did you get that power readings after you switched the blue wire from OB to C? If yes, try to switch back your thermostat wiring from its original configuration then gather the power readings to compare. Also, please share with us the photo of the wires connected to your system's control board. Ensure that the labels of the wires are visible.
Best regards,
Jenelyn
11-21-2023 08:17 AM
Yes I got that error after switching from the O/B over to the C. I will upload photos of the wires and power settings now.
11-21-2023 08:27 AM
11-21-2023 08:35 AM
Hey Socalgirl415,
Thanks for providing the photos above. It turns out that your blue wire isn't the C wire, but a wire for the heat pump. Checking your Nest Thermostat's Energy History would tell us what your thermostat is doing previously.
Please keep me posted.
Regards,
Jenelyn
11-21-2023 08:56 AM
When I try to use the heater it just blows cold air. I can’t get warm air to come from the heater.
11-21-2023 08:56 AM
11-22-2023 09:06 AM
Hello there Socalgirl415,
Thanks for keeping me in the loop. To confirm, in what country are you located? Please take a photo of the wires connected to your system's control board. It will help us to ensure the wiring configuration of your system. Also, what is the make and model of your system?
Kind regards,
Jenelyn
11-22-2023 09:21 AM
I’m located in the US.
11-22-2023 09:22 AM
11-22-2023 09:23 AM
11-25-2023 10:42 AM
Hey folks,
I'm dropping by to ensure everything is covered here.
Thanks for looking into this, Jenelyn.
@Socalgirl415, we appreciate the added details. Looking through the conversation, it appears you have configured your thermostat with a heat pump system. With this, please move the blue wire to the C terminal and leave the white wire at the W1 terminal to avoid the wiring report. Once the wire has been changed, make sure to restart your thermostat to correct its configuration.
Note: Turn off the power from your HVAC system at the breaker box before touching a wire.
Let us know how it goes.
Best regards,
Mark
11-25-2023 06:20 PM
Hi mark! I tried that and still receive a no power error. I’ll attach photos.
11-25-2023 06:21 PM
11-25-2023 06:21 PM
11-26-2023 09:14 AM
Hi all,
@Socalgirl415, chiming in—thanks for getting back to us. After moving the blue wire to C terminal, gather again the Battery, VOC, VIN, and lIN power readouts of your Nest Learning Thermostat under Setting > Technical Info > Power. Also, make sure the thermostat wires are properly stripped and seated in the thermostat base. If the issue still persists, kindly disconnect the C wire then see if the error code no longer shows on the display.
Thanks for your help here, Jenelyn and Mark.
Best,
Zoe
11-26-2023 07:32 PM
I switched to my old thermostat and the heater is working fine so it is definitely a wiring issue with the nest thermostat.
11-27-2023 06:40 AM
Hi there Socalgirl415,
Don't give up on us yet—we'd like to further check on this. Could you fill out this form and let me know once you're done?
Thanks,
Zoe
11-27-2023 07:28 AM
form completed
11-28-2023 11:52 AM
Hello again,
Thanks for completing the form; we have received it. Soon, a member of our senior support team will contact you via email. So please keep an eye out for any updates and continue the conversation there for any inquiries.
Warm regards,
Mark