Why is My Furnace Not Staying On

Does it feel cold in your house? if you notice that your heater kicks off before the house gets warm, there could be a problem.  In addition to being uncomfortable, an inefficient heating system can lead to higher utility bills, even if you don’t think the heater is running when it should.

Common Furnace Issues

Here are a few things that might be happening if your furnace isn’t staying on.

1. Broken Thermostat

The thermostat may have faulty wiring or just need new batteries. When the thermostat is not working as expected, the furnace may receive a signal that the room temperature is higher than it really is. This can cause the furnace to turn off after only a couple of minutes.

2. Bad Thermocouple

For gas-powered HVAC systems, the thermocouple next to the pilot light opens and closes the gas valve. However, a malfunctioning thermocouple can cause the gas valve to close randomly. You can usually tell that the gas has been shut off from the system if your pilot light won’t stay lit.

3. Too Much Condensate

Some furnaces generate condensate. If the drain line becomes clogged, the condensate may overflow the condensate pan. A sensor may shut off the furnace so that water damage doesn’t occur. If you do have a blocked condensate line, you can try to remove the clog or call a professional.

4. Blower Motor Issues

Sometimes the issue with a non-functioning furnace is the blower motor and not the furnace itself. HVAC systems have a safety mechanism that shuts off the furnace to prevent overheating. When the blower doesn’t run as expected, you may still be generating heat but it is not being distributed through the ductwork. The fan relay might be broken or it may just be a belt. It’s best to call a repairman to find the exact cause.

5. Clogged Air Filter

Probably the most common cause of furnaces not running properly is a clogged air filter. Restricted airflow can cause overheating, the same as blower motor issues. Furnace filters should be changed every 1-3 months or more if you have a lot of pets or dust in your home. You should receive a new filter during your regularly scheduled maintenance call and you can request additional filters for the upcoming months.

6. Dirty Sensors

If you smell gas just prior to the furnace kicking on or if the furnace does not stay on as long as it should, it could be the fault of a dirty ignition sensor. The ignition sensor is a safety device that detects flames and turns off the furnace when there are none to prevent gas from escaping into your home. Call a technician if you suspect a dirty sensor is causing your furnace to not stay on.

Contact IAQ today to schedule your annual HVAC maintenance appointment. We serve homes in Highlands Ranch and throughout the Denver Metro Area.