Why Is My Heating System Not Working? | Honeywell Home

Why is my heating not working? If your heating is not working, it's probably due to issues with the following:

Air Flow
Heating or Furnace System
Thermostat Wiring
Thermostat Screen
Thermostat Functionality

To begin fixing your heating, continue to the Air Flow section.

Air Flow
Go to your vents

What best describes the air coming out of your vents?
- NO AIR – Continue to the Furnace or Heating System section.
- ROOM TEMPERATURE – Continue to the Thermostat Functionality section.
- WEAK HEAT (WARM) – Continue to the Fan section.
- COLD – Continue to the Thermostat Functionality section.
Heating or Furnace System
Go to your home's circuit breaker

Make sure the breaker to the furnace is turned on

Go to your furnace or heating system

This system is often located in your basement, attic, or garage.

Make sure your furnace is turned on
There's usually a switch next to your furnace that turns it on or off. It sometimes looks like a light switch.
Make sure the furnace cover is closed.

Be sure the cover is completely closed. Some systems won't power up if the cover isn't fully closed.
Are there any error lights on the furnace?

Most furnaces have lights on them. When there's an error, this light will flash or blink rapidly. There's typically an error code reference guide inside the furnace cover.
- YES – Contact the manufacturer of your furnace, or contact Support at 1-855-733-5465 to find a pro-installer in your area.
- NO – Continue to the next step.
Go to your vents
Do you feel any air?

It doesn't have to be hot air.
- YES – Continue to the Thermostat Wiring section.
- NO – Contact Support at 1-855-733-5465 to find a pro-installer in your area.
Thermostat Wiring

Go to your thermostat
Remove your existing thermostat from the wall plate

On most thermostats, you can take off the thermostat by grasping and gently pulling. Some thermostats may have screws, buttons, or clasps.

Note: Don't remove any wires from your thermostat at this time.
Do you have wires connected to any of the following terminals?
- W: Continue to the next step.
- O/B: Continue to the next step.
- W-O/B: Continue to the next step.
- W & O/B: Disconnect the wire connected to W and insert it into W2. Leave O/B alone. Continue to the next step.
Go to your vents
Is your heating working now?
- YES – Congratulations! You've fixed your heating! You are now complete.
- NO – My heating isn't working, but I'm still feeling air flow. Continue to the Thermostat Screen section.
Thermostat Screen

Go to your thermostat
Does the thermostat show any of the following icons or messages?
- "Heat"
- "Heat On"
- Fire Icon
- Sun Icon
- YES – Continue to the next step.
- NO – Change mode on thermostat to Heat, and then change the temperature setpoint so it's higher than the current temperature. Afterwards, continue to the next step. *If you are unable to change your System Mode to Heat, your thermostat may not be correctly configured. Locate the Installer guide for your model and verify your settings are correct for your System Type and Heat Stages.*
Check the thermostat screen again: are the icons or messages present?
- YES – Continue to next step.
- NO – Contact Support at 1-855-733-5465 to find a pro-installer in your area.
Are the icons or messages flashing?
- YES – If the icons or messages are flashing, this means your compressor protection is on. Wait for 5 minutes until the icons or messages stop flashing, and then continue to the next step. If after 5 minutes, the flashing doesn't stop, contact Support at 1-855-733-5465 to find a pro-installer in your area.
- NO – If the icons or messages aren't flashing, this means your heat should be working. Continue to the next step.
Go to your vents
Is your heating working now?
- YES – Congratulations! You've fixed your heating! You are now complete.
- NO – Contact Support at 1-855-733-5465 to find a pro-installer in your area.
Thermostat Functionality

Go to your thermostat
Switch your thermostat from Heating to Cooling.

Go to your vents
What temperature do you feel blowing from the vent?
- COLD – This means your thermostat is cooling correctly, but the heating isn't working properly. Contact Support at 1-855-733-5465 to find a pro-installer in your area.
- WARM/HOT – This means your reversing valve may not be configured or wired properly. Continue to the Thermostat Wiring section.
Fan

Go to your thermostat
Turn your fan mode on.

Go to your vents
Is your heat working at full force (not weak)?
- YES – There's nothing wrong with your system, but it's not correctly configured. Contact Support at 1-855-733-5465 to find a pro-installer in your area.
- NO – Continue to the next step.
Go to your thermostat
Remove your existing thermostat from the wall plate

On most thermostats, you can take off the thermostat by grasping and gently pulling. Some thermostats may have screws, buttons, or clasps.

Note: Don't remove any wires from your thermostat at this time.
Do you have a wire connected to the G-Terminal?
- YES – Since you have a G-Wire, but your fan isn't working properly, your system may need servicing. Contact Support at 1-855-733-5465 to find a pro-installer in your area.
- NO – You require a G-Wire to run your fan. Contact Support at 1-855-733-5465 to find a pro-installer in your area.
Is it time to upgrade your thermostat? Let us help you make the right choice for you and your home with our thermostat upgrade guide.