Furnace stopped heating-But Nest shows it is working

[ColleenH]

The Nest is connected to a forced air LP furnace. It has funtioned properly until today when it shows it is heating but the furnace does not heat. Here are the steps I have tried:

1. Change mode from heat to off and back to heat.

2. Restarted Internet

3. Changed batteries 

4. Restated Nest

5. Turned power to furnace off and back on.

What else can I try to fix this issue??

[maedacortez]

Hi ColleenH,

Thanks for reaching out. I understand that the heating has stopped working, and I'm happy to assist you! Before we continue, I need to ask a few questions to better understand the situation:

• "What type of Nest thermostat do you have?"
• "When did the issue start?"
• "What other unusual symptoms have you experienced since the problem started?" (or "What other symptoms have you noticed since the problem started?")
• "Are there any error messages? If so, what are they exactly?"
• "When was the last maintenance check for your HVAC system?"

I will be waiting for your response.

Regards,

Manuel

[Patrick_Caezza]

@ColleenH 

You said you changed the batteries. Neither of the Learning Thermostats (3rd or 4th Gen) has replaceable batteries. Only the Google Nest Thermostat (2020) has replaceable batteries.

How is the thermostat wired? 

Can you post a picture of the baseplate wiring here?