6 Reasons Why Your Heater Isn’t Working


Every year, heating systems get put to the test as temperatures drop. Unfortunately, sometimes your system’s furnace will stop working without much warning.

If your central heating system is unable to produce warm air, one of these issues is usually the cause.

1. Blocked Air Vents

If your furnace is producing warm air for some rooms but not others, your furnace is probably fine. The issue is most likely with your ductwork. First, check for any air vents on your walls or floors that might be covered up by rugs, curtains, or furniture. Make sure the registers covering the vents are open. If your ductwork has dampers inside it to control airflow, also make sure to open them up.

2. Clogged Air Filter

If your furnace is producing weak airflow or keeps shutting down, that’s a strong indicator that your system’s air filter is far overdue for a change or a cleaning. Once you change or clean the air filter, your furnace will most likely start working again.

When your air filter gets blanketed with dust, it keeps the proper amount of airflow from moving through your heating system, which can lead to several issues. Depending on what type of air filter you have, make sure to replace it or clean it regularly and to check on it frequently.

3. Improperly Set Thermostat

If your furnace won’t turn on, or if it’s producing air that isn’t warm, check your thermostat. Sometimes the thermostat will be set to “cool,” or the fan will be set to “on” without heating or cooling your home. Make sure that your thermostat is set to “heat.”

To ensure the system is working, set the thermostat 5 degrees higher than the current room temperature so that the furnace will turn on. If the furnace does not turn on, and if your thermostat uses batteries, replace the batteries. If you keep getting an error message from your thermostat, you may need to reset it, or it may need a professional repair.

4. Tripped Circuit Breaker

Because gas and electric furnaces use so much energy, sometimes they will trip their respective circuit breakers. First, make sure your furnace is switched on, then go to your electrical panel. Locate the circuit breaker associated with your furnace. If the breaker was tripped, switch it back on. While this problem is common and something you can solve on your own, you should consult an HVAC technician if your furnace continues to trip the circuit breaker.

5. Dirty/Faulty Ignitor or Ignition Sensor

When you switch your gas furnace on, does it click but not ignite? If so, then there’s probably an issue with your ignitor or ignition sensor. If the ignition sensor isn’t able to “sense” the flame, it shuts down the whole unit as a safety measure.

In some cases, these parts only need to be cleaned to start working correctly again, and this is something that some people are comfortable with attempting on their own. However, if one or both of the parts are faulty, contacting an HVAC technician for a professional replacement is safest.

Keep in mind that a furnace ignition with a standing pilot light can take a little while to ignite when you first turn it on for the season. It can take some time for the fuel from the gas line to reach the pilot light.

6. Dirty Blower Motor

A dirty blower motor can inhibit airflow through your furnace, which can cause the unit to overheat and shut down. A cracked heat exchanger often indicates a dirty blower motor because the heat exchanger relies on the blower motor to move cool air continuously through the system.

It’s crucial to replace a cracked heat exchanger as soon as you discover it. Not only will it make your furnace run less efficiently, but it will leak carbon monoxide. The simplest way to catch and prevent dangers like this one is annual heating system maintenance, which involves a safety inspection of the system’s components.

Having trouble with your heating system? Call Carter Comfort Systems today at (208) 739-4181 or contact us online for client-focused heater services in Caldwell or Boise. We offer free estimates!