Why Won’t My Heater Stay On?

By January 28, 2019 February 1st, 2022 Heating

As temperatures drop in the midst of the winter season, you might become reliant on your heater to keep your home as comfortable as possible. However, if you notice your heater doesn’t stay on and heat the whole house like it used to, there could be an unexpected problem. No one wants their heater blowing cold air!

Troubleshooting your heater is an important step in figuring out what might be wrong with it, but barring that, you should always involve an experienced HVAC technician to repair and, if necessary, replace your furnace.

Take a look at a few things that might be happening with your heater if it fails to heat the whole house and what to do about it.

Common Reasons Why Your Furnace Shut Off Unexpectedly

  • Dirty flame sensor – Your flame sensor is an important component of your furnace, as it can detect the pilot light is working properly. If this sensor becomes dirty, the furnace will shut off. This is one of most common problems HVAC technicians see when diagnosing a furnace that has suddenly stopped working. If you plan to clean this yourself, shut the power off to the furnace, then remove and clean the flame sensor. If you’re nervous about doing this or would rather a professional handle it, then call an experienced furnace repair technician for help.
  • Dirty furnace filters – Another common furnace problem, dirty furnace filters can cause your furnace to shut off because dirt and debris buildup causes the furnace to have to work harder, leading to a shut off when the heat exchanger becomes overheated. To avoid furnace shut off from a dirty furnace filter, be sure to change out your filters frequently, especially during times where your furnace is used more often, as it will become dirty faster. If you have already changed the air filters but the furnace still continues to have problems, continue troubleshooting or contact a technician to see if they can figure out what is causing the problem.
  • Malfunctioning thermostat – If your heater is not running or shuts off, your thermostat might need to be adjusted. If this seems like an obvious solution, it might be! However, it is completely common to forget to set your thermostat correctly, especially as the seasons change and you’ve been using your air conditioner. You can test your thermostat by raising the temperature slowly and having another person stand by the furnace to see if it turns on. When this is done, both the thermostat and furnace should make a clicking sound to indicate they are functioning. If neither of you notice this happening with the thermostat or the furnace, you may need to replace the thermostat which is luckily cheaper than installing a whole new furnace. If a replacement thermostat doesn’t help, then it’s time to look for other possible causes of your problem.
  • Malfunctioning or broken thermocouple – The thermocouple is a sensor which detects the pilot light’s functionality. If your pilot light goes out, the thermocouple reacts by shutting off the gas valve, keeping your home safe and avoiding it from filling up with gas. If the thermocouple stops working properly, it might shut the gas valve off at random intervals, causing the furnace to function improperly. A sign that the thermocouple needs replacing can be that the pilot light fails to stay lit and keep the furnace running, but only an experienced HVAC technician can know for sure if replacing this part will solve your heater problem.
  • Condensate pan is full – When liquid cools after your furnace heats your home, the condensation drips down into a pan and drains away from the system. However, the drain line between the condensate pan and the drain can become clogged over time, causing the pan to fill up. If the pan is too full, the furnace has a mechanism that shuts it off automatically for safety reasons—namely, to avoid the condensate pan from spilling liquid because the drain line is clogged. Cleaning the drain line using a pipe cleaner and a mixture of bleach and water can do the trick, but if you’re not comfortable with doing this, a technician can help inspect your furnace and advise on a maintenance plan designed for your needs.
  • Blower motor has stopped running – The blower motor helps move hot air from your furnace through your ventilation. However, if the blower motor becomes dirty or has lost power, the furnace will switch off to keep you safe and avoid other problems, such as the heath exchanger overheating and breaking down. The best way to find out what is wrong is to contact an HVAC company and schedule an appointment to have a technician figure out the problem and repair it.

Contact a St. Louis Furnace Repair Company

It can be frustrating when your furnace stops working, but you don’t have to be out in the cold for long. Contact Design Aire today to schedule an appointment with one of our talented technicians. We are more than happy to inspect your furnace and fix it in no time, bringing warm air back into your home once again!