Central Heater Not Working [7 Easy Solutions]

Is your central heater not working? The last thing you want to do is come home or wake up to a cold night and notice that your central heat is not turning on. There are some days in winter that can get close to freezing, and if it is on one of those days your heater stopped working, then surely it can leave you and your loved ones miserably cold. 

Your central heater not working is something that you should not ignore because not only can this leave you feeling uncomfortably cold, but it isn’t healthy for you and your pets too.  

There are many reasons for your central heat not working, some are ‘easy’ fixes that you can get your hands on and bring your heater back on while other issues require professional help. 

In this guide, I have put together common reasons that stop the central heater from working properly or not working at all. And, as always, we have also provided possible solutions to each of the problems. Where we think, you might need to call in HVAC professionals for help, we have advised so accordingly. 

Why is My Central Heater Not Working? 

There are countless reasons your central heater could have stopped working. To quickly troubleshoot your heater problems, make sure you check the following possible issues.  

1. Heater’s Power Switch is Off

 When your heater is not working, the first thing you want to check and rule out is the heater’s power switch. If it is turned off, turn it on. 

The heating system’s power switches are more often than not mistakenly or accidentally switched off. If you were recently in the attic to collect holiday decorations or if you had any of the technicians do some work near your furnace, your power switch could have mistakenly been turned off.  If you check and find that your power switch is ‘ON’ move on to the next step.  

2. Check Your Heater’s Circuit Breaker

The quickest way to troubleshoot a central heater that is not working is to first check the circuit breaker. Make sure your heater’s breaker has not tripped. If it has, resetting it should get your heater back to running.  

Heating systems come with built-in safety measures. So, if there was some overheating somewhere in the electrical wiring or if there was a power surge, your breakers might have tripped. And if breakers trip again after resetting them, it’s a sign that there might be a serious problem that needs attention. In this case, calling a professional and licensed HVAC technician to come and have a look is in order. 

3. Check if Your Furnace Air Filters Are Dirty 

After you check your heater’s power switch, and the circuit breakers and things seem to be all fine, it is now time to check the HVAC air filters. Dirty or clogged air filters cause different problems with your heating system. If your heater is not turning on at all then, ignore this step.  

Clogged air filters will restrict the airflow into your heating unit, and when this happens two things can happen:

1. There won’t be enough air to be heated in the heat exchanger. Not enough air in the heat exchanger means less air has been heated. When there is less air being heated, your furnace will not blow out hot air.
2. And if the air getting into your heating unit is restricted, this will cause your system to overheat. When overheating takes place, your central heater’s safety measure will shut off your heating system, to protect critical parts from damage. When this happens, the blower fan can still continue blowing cold.

However, if your heater is turning on but not blowing hot air better pay attention to this tip. Air filters remove dirty, pollen, and other substances before the air get in your furnace or heat pump. They preserve other components of your heating systems such as the blower fan. 

If your environment has lots of dust in it and you have pets at home, air filters can easily become dirty or clogged. When they do, they will restrict the airflow into your furnace that has to be heated. So, no hot air will be blowing out of your vents. 

If dirty air filters are not replaced with clean ones, they will cause your system to overheat and eventually shut down, sometimes causing your furnace to short cycle. To check the status of your air filters, remember to turn off your system for safety. And when you are done, close the door. If the door is not closed correctly your system won’t start. 

The standard recommended period to use air filters before a replacement is 3 months. Filters are inexpensive and if you have pets around, you can replace them more often to keep your system running efficiently.  

4. Check Your Thermostat For Any Issues

Another common reason for your HVAC system not working is a thermostat that is malfunctioning or not properly set. But before you go on to check if your thermostat is malfunctioning, make sure your thermostat batteries are not dead or weak.  You’ll be surprised to know that weak batteries are the biggest culprit for a thermostat that is misbehaving. 

Of course, a thermostat is there to regulate the heat from your furnace. However, over the years, just like any other appliance your thermostat may need some repairs or probably a replacement. 

If batteries are fine but there is still an issue with your thermostat, chances are, your thermostat might not have been properly programmed.  Because you are able to set different temperatures of the day with a programmable thermostat, it is frustratingly easy to make a mistake in programming. You might have inadvertently set it to a point you don’t want. 

So, what should you do for a thermostat that does not turn on the heat? The best solution to this is to ensure that the thermostat is correctly programmed. If you are uncomfortable with anything, it is wise to call in a licensed technician. 

5. Low Refrigerant Levels In Your HVAC System 

Do you use a heat pump system for heating your home? If your answer is yes, this tip is for you. When the refrigerant is low or leaking from your HVAC system it can cause two things to happen, 

1. The heater will turn on but will be blowing cold air: This is because the refrigerant is the one that transfers heat between the outdoor air and your inside home. So, when there is no more refrigerant, there won’t be any heating coming into your home. Even though the blower fan can keep running, nothing but cold air will come out of the vents. 

2. The compressor can overheat and then break down where there is completely no refrigerant left, and the issue is not solved.  When this happens, the system will shut down completely. 

6. Blower Capacitor Not Working 

The blower capacitor is the one that’s responsible for starting your furnace. Once the set point on the thermostat is reached, the capacitor will start your furnace. Unfortunately, if your furnace is old, so will your blower capacitor be if it has never been replaced before. If you think you might have a dead blower capacitor, consider replacing it. But before doing that, consult HVAC professional on this.  

7. Central Heat Not Working: Check Blower Motor

The blower motor blowers the warm air from the furnace into your home. Sometimes the blower motor can malfunction due to many reasons including dirty air filters. When the blower motor stops working, there will be no air that will be blown into your home. You can tell if the blower motor has a problem if its wheels are slowly turning and immediately turning off. 

8. Dirty Flame Sensors

Dirty flame sensors are common causes for your central heat not working. A furnace flame sensor is a straight or L-shaped metal rod that is found behind the burners.

Flame sensors are there to detect flames in your furnace. If they can’t detect flames in about 10 seconds, they will close the gas valve to prevent any gas leak into your home. A dirty flame sensor can also cause your furnace to start short cycling.

Over the years, dirt and other substances can accumulate on the sensors, making them difficult to sense the flames. This is how you clean them.

• Switch off the furnace either at the power switch or, the thermostat.
• Remove the metal cover and locate the flame sensor.
• If there is a lot of build-up on the sensor, gently rub it with steel wool or sandpaper.
• After you are done, put the sensor in its position before turning your furnace on.

FAQS on Central Heater Not Working

 Solution: If your thermostat is battery powered and is misbehaving, replace its batteries. If this doesn’t help, call in a professional to come and have a look. 

 Solution: Regular maintenance will keep your furnace or heater in good working condition. Check if your furnace air filters are dirty. If they are, replace them. You have to replace your HVAC air filters at least once every 3 months. 

Solution: Quickly check if your air filters are dirty. You need to replace them if they are dirty. This should fix this problem. 

Why is My Central Heat Blowing Cold Air?

If your central heat is blowing cold air instead of hot, it could be a sign of any of the following.

• Your fan is set to “ON”. Either set it to ‘heat’ or ‘auto’ to fix this issue.
• If you are using the heat pump, this could be a sign that the refrigerant is low or leaking. Call in an HVAC technician to come and check the refrigerant charge.

How Do I Reset My Central Heating System?

You can reset your heating system by the following.

1. Turn off your furnace either on its power switch or by tripping the circuit breaker.
2. Locate the reset button of the furnace, which is usually found in the blower compartment.
3. Push the reset button down if it is popped.
4. Put back the blower compartment cover.
5. Turn your furnace on.

What to Check if Heat Is Not Working?

When your central heating is not working, this is what you need to check first.

1. Check the power switch of your furnace if it’s in the off position. If it’s not in the off position but your heater is still not working, then check your circuit breaker if it has tripped. If it has tripped, reset it.
2. Your thermostat: Ensure that your thermostat is set correctly. If you are using a programmable thermostat, make sure that it’s correctly programmed.
3. Air filters. They are found at the return ducts. Check them and find out if they are dirty. If they are, replace the. Remember to change air filters once every 3 months.

Final Thought On Central Heating Not Working

There can be any number of reasons for your central heat not working in the house but the ones we have discussed in this article are the most common ones. Before calling in HVAC professionals, try out the possible solutions that we have provided in this article. You’ll be surprised by how quickly you will solve your heater’s problems.

Resources

https://www.aireserv.com/about/blog/2020/november/why-does-my-furnace-keep-tripping-the-reset-butt/

Tim David

HVAC tech with over 30 years of experience. Retired and doing repair work on the side around Madison County, AL.