The thermostat says heat on but furnace not running? It is almost the same situation we’ve discussed in the article My Thermostat Clicks, But the AC Does Not Turn On, This common issue can be frustrating, mainly when you rely on your heating system to keep your home comfortable during the colder months.
Do these 6 Things if dealing with a thermostat that says heat on, but the furnace is not running:
The thermostat acts as the control center for your heating system, and you send signals to the furnace to turn on or off based on your selected temperature settings.
When the thermostat displays “Heat On,” it indicates that it has sent a signal to the furnace, instructing it to start heating the home.
However, if the furnace fails to respond and doesn’t kick into action, there could be several reasons for this malfunction.
The first step to solving any electrical appliance is to ensure it has power. Start by checking if the furnace is receiving electricity.
Check the electrical fuse or circuit box to see if the circuit supplying power to the furnace has tripped or blown a fuse.
If so, restart the breaker or replace the fuse and see if the furnace starts running again.
Sometimes, the issue might be as simple as incorrect thermostat settings. Ensure that the device is adjusted to “Heat” and that the climate setting is higher than the current room temperature.
Additionally, check if the thermostat’s batteries need replacing, as a low battery can cause communication errors.
Learn more in our article: Is Your Thermostat Not Working? This Is What You Need to Do!
If the power supply and thermostat settings are in order, the next step is to inspect the furnace.
Start by checking the filters. A congested or dirty filter can restrict airflow and cause the furnace to malfunction.
As said in our article about Air conditioners not blowing cold air but running, you need to check your air filter monthly and replace it when clogged or dusty. Look for filters with a MERV rating (Minimum Efficiency Reporting Value) appropriate for your needs.
Inspect the area around the furnace for obstructions blocking airflow. Ensure that vents and registers are open and unobstructed for proper air circulation.
Additionally, check the furnace’s intake and exhaust vents for any blockages, such as debris or snow buildup, especially if the stove is outdoors.
Many modern furnaces have diagnostic systems that display error codes to indicate potential issues.
Refer to your furnace’s manual to interpret any error codes displayed on the control panel.
These keys can provide valuable insight into what might be causing the furnace to malfunction.
If you’ve tried the above steps and still haven’t solved the issue, it may be time to seek professional assistance.
A qualified HVAC technician can thoroughly inspect your burner, identify the root cause of the problem, and perform any necessary repairs or replacements.
Dealing with a thermostat that says heat on, but the furnace not running can be a heat-scratcher situation, especially during the colder months. However, with the explained causes defined in this article, you can systematically diagnose and potentially resolve the issue yourself, if it is something like replacing the filer.
You can count on AAC Heating and Air INC. We have 25+ years of experience and can help you if your thermostat says heat on, but furnace not running. With our professional HVAC maintenance services you can rest assured that you’ll have a heating system that will last for decades to come, working at its best!
