Heat/fan not working on gas furnace/forced air system

[richardlr]

I have a forced air heating/AC system that was working completely until the previous thermostat failed (LCD display failed). Installation seemed to go smoothly; connected to Wi-Fi and a Google account. The AC+fan works, fan solo works, but heat+fan does not work. When the heating should come on, neither the fan nor the furnace comes on. The thermostat is connected to Y-W-G-R and a power test is successful (Vin:34.774V, lin: 385, PS:Y-385 YP-2). 

[zoeuvre]

Hi richardlr, 

Thanks for bringing this to our attention, and I'm sorry to hear about the situation. I want to check if you are still in need of any help. If so, please answer the following:

1. Where are you located? From North America or Europe? 
2. Is the Nest thermostat newly installed?
3. Does the thermostat screen indicate that it’s actively calling for heating?
4. What type of furnace do you have? (gas, electric, etc.)
5. When did heating last work?
6. Did heating ever work with the Nest thermostat?
7. Did you turn off the power to the HVAC system?
   • Did you recently turn off any breakers?
   • Have you recently experienced a brownout or blackout?
   • Is there a light switch near the heater that controls an outlet?
8. Did you select the correct fuel type?
9. When was the last time you changed the furnace's air filter?
    

Also, please send us a photo of your old thermostat and how you wired it to the Nest Thermostat base, and gather the power readouts from your thermostat. Go to Settings > Equipment > Power Info.

I'll look forward to your response.

Best,

Zoe 

[richardlr]

Zoe, thanks for your help:

1. North America

2. Yes

3. Yes

4. Gas

5. June 2023

6. No

7. No, I checked the breakers and two fuses on the furnace itself; No power loss; No light switch

8. Yes

9. I replaced the air filter when trying to debug the problem. 

I see no way to send you a photo with this reply, is there an email address I can send them to? The thermostat is connected to Y-W-G-R and the power readout is: Vin:34.774V, lin: 385, PS:Y-385 YP-2

Thanks again! 

[richardlr]

I found the icon for photos. I hope these are what you want.

[zoeuvre]

Hi there, 

Thanks for the follow-up information. Let's give these stepa a try: 

1. Remove the Y1 wire.
   • At the breaker box, turn off the power to the HVAC system.
   • Remove the Y1 wire, cover its metallic part with electrical tape or a wire cap, and tuck it into the wall.
   • Turn the power back on at the breaker box.
   • Call for heat (set the thermostat to heat mode), and check if the system activates runs. Some systems take time to start up, so wait up to 5 minutes for the heat to turn on.

Let us know how it goes. 

Regards,

Zoe