Furnace Running But No Heat? Fix This Now
When your furnace is running but fails to generate adequate warmth, it's frustrating. But some simple troubleshooting steps can get heat flowing again before calling a professional.
Check Thermostat Settings
The first place to inspect is your thermostat. Ensure it is set to "heat" mode and the temperature is raised above the actual room temperature. Also check that the thermostat wiring is intact and securely connected to the base and wall.
Try replacing old batteries if applicable. Battery failure is a common cause of furnace communication issues. Or use the manual temperature override options if available. This verifies whether the thermostat is properly signaling the furnace to ignite and distribute heat.
Accessing Thermostat Settings
Thermostats have a settings menu to control modes, schedules, and target temperatures. To access it, look for a "Menu" button on the face of the unit or scroll through the digital display options.
Adjusting Temperature Setpoints
Increase your heating setpoint minimum to at least 3-5 degrees above the room temperature. You can also adjust the furnace schedule to call for heat during specific periods. These adjustments prompt the thermostat to communicate calls for heat to the furnace.
Examine Air Filter
A dirty, clogged air filter inhibits airflow through the furnace and ductwork. This prevents heated air from circulating properly. Locate your furnace filter and check its condition. Replace filters 3 months or more. If very dirty, replacing it can increase airflow and heat output.
Ensure Vents & Registers Are Clear
Check that all vents and registers are open and unblocked throughout your home. Closed vents and obstructions like furniture blocking registers make it harder for hot air to get where needed.
Diagnose Pilot Light Issues
For gas furnaces, an extinguished pilot light halts ignition sequence and heat production. Locate the pilot assembly and try relighting with the manual igniter if equipped. Also check the thermocouple isn't faulty. This sensor indicates the pilot status to the gas control valve. If issues reoccur, replacement may be necessary.
Evaluating The Flame Sensor
Like the thermocouple, the flame sensor verifies furnace ignition status. Over time, sensor contacts can accumulate debris buildup. Try cleaning gently with steel wool to maintain a clear signal. Don't force connections loose in the process. Severe soot or corrosion may warrant calling a technician to replace components.
The blower motor pushes heated air through ducts to your living spaces. Verify that it activates when heat is called from the thermostat. Feel for airflow from vents to ensure it spins and isn't stuck. Blower motors can wear out over longtime use. Have an HVAC pro assess blower operation if you suspect issues or hear abnormal noises.
You can often get a hot furnace running again without waiting for a service appointment. But if you confirm more serious problems like heat exchanger cracks or control board failures, don't delay calling in an expert for emergency repairs.