Learning thermostat shows heating. But the furnace is not on.

[Mizzen]

This has happened on two occasions in the past month. I'm not sure when I did to fix it on the first occasion. It's done it again today. Furnace is the alternate heat as the heat pump is the main source. Any thoughts on what my problem is?

[Jenelyn_O · Accepted solution]

Hi Mizzen,

Thanks for reaching out. I'm sorry for the trouble this may have caused you. I'd like to know more about it. A few questions: what type of Nest Thermostat do you have? What is the make and model of your heat pump system? Also, in what country are you located? 

Best,

Jenelyn

[Mizzen]

Hi. Sorry for my delayed response. I have a Nest Learning thermostat gen 3. The heat pump is a Trane xr15. I am located in Ohio, USA. 

Thanks for your help.

[zoeuvre]

Hi folks,

@Mizzen, chiming in—let's see what's going on. A few questions: 

• What type of furnace do you have? (gas, electric, etc.)
• When did heating last work?
• Did heating ever work with the Nest Thermostat? If not, did the heating work with the previous thermostat?
• 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?
• Did you select the correct fuel type?
• Do the LED lights blink on the HVAC control board? If yes, locate the light.
• When was the last time you changed the furnace's air filter?
• Have you experienced extremely cold weather lately?
• Is this the first notable temperature drop of the year in the area?

I appreciate your help, Jenelyn. 

Best,

Zoe

[Mizzen]

We have a gas furnace and an electric heat pump (both heat types match of the thermostat). The heat pump is set to take over heating when the outside temp is above 40 Fahrenheit. There has been no problem with the heat pump. The outside temp has been below 40 plenty of times for the past 45 days. And the furnace works fine most of the time. The problem is that it occasionally takes 10+ minutes to start heating from the time the thermostat indicates it is time to start heating. This is most obvious to me when I get up in the morning, go to the app, and tell the raise the temp on the thermostat. The furnace will click during this time and make brief moves to fire up, and then eventually start heating. I have cleaned the filter.  I added the Nest thermostat in Sept. So I am not sure if this was an issue previously. We moved into the house in May. Thanks for any suggestions.

[Markjosephp]

Hello everyone,

I'm dropping by to see how I can help.

Thanks for your assistance here, Zoe.

@Mizzen, it sounds like you're experiencing some delay issues with your gas furnace, especially when initiating heating after adjusting the thermostat. While it's great that your heat pump has been working well, the delay in the furnace starting up could be a concern. Since you've already cleaned the filter and added a Nest Thermostat recently, it's a good idea to check a few more things:

1. Verify that your thermostat settings are configured correctly. Double-check the schedule, set points, and any programming related to the gas furnace. Make sure there are no conflicting schedules or settings that might be causing delays.
2. Even though you've moved in recently, it's worth considering a professional inspection and maintenance for your gas furnace. Delayed ignition could be caused by issues such as a faulty ignition system, gas valve problems, or other mechanical issues that might need attention.
3. Check the outdoor venting for any obstructions or blockages that could be affecting the furnace's ability to start promptly. Proper ventilation is crucial for the furnace to function efficiently.

Let us know how it goes.

Warm regards,
Mark