Why Central Heating Not Working?

It’s the middle of winter, and your central heating system isn’t working correctly. You’ve had to crank up the heaters in each room to combat the cold, but it’s not enough. So, why is your central heating not working?

The causes of central heating not working include a damaged flame sensor, faulty filter, faulty pilot light, cracked heat exchanger, or worn blower motor. Easy fixes include replacing the sensor, cleaning the filter, fixing the pilot light, and replacing the heat exchanger and motor.

It can be a hassle when your central heating is not working. Not only is it uncomfortable to live in a cold home, but it can also be costly to run your heaters all the time. If you’re dealing with a faulty central heating system, here are a few potential causes and what you can do to fix them.

1. The Flame Sensor Is Dirty or Damaged

The flame sensor is a small rod that sits in the burner assembly of your furnace. Its job is to sense when the pilot light is lit and to turn on the gas flow to the burner. If the sensor is dirty or damaged, it may not be able to correctly detect the pilot light, which will prevent the furnace from igniting.

Besides, a damaged or dirty flame sensor can also cause the furnace to cycle on and off frequently, wasting energy and driving up your utility bills.

Here are additional signs that your flame sensor may be dirty or damaged:

  • The furnace is not igniting.
  • The furnace is cycling on and off frequently.
  • The pilot light is lit, but the burner does not come on.
  • The furnace makes a clicking noise when it tries to ignite.

Read: What Type Of Heating Systems Do Apartments Have?

How To Fix?

If you think your flame sensor may be dirty or damaged, the best thing to do is clean or replace it.

Tools needed:

  • A screwdriver.
  • A wire brush or other small brush.

Here are the steps you’ll need to take:

  1. Turn off the power to your furnace at the breaker box.
  2. Remove the access panel to the burner assembly.
  3. Locate the flame sensor and use a wire brush or other small, soft-bristled brush to clean it.
  4. Be sure to brush away any dirt, dust, or debris on the sensor.
  5. If the sensor is visibly damaged, replace it.
  6. Reattach the access panel and turn on the power to your furnace.

Caveat: The above is a relatively simple and inexpensive repair that you can do yourself. However, if you’re not comfortable working with gas lines and electrical components, it’s best to leave this repair to a professional.

2. The Furnace Filter Is Dirty or Damaged

The furnace filter is responsible for trapping dirt, dust, and other airborne particles that could clog up the inner workings of your furnace. Over time, the filter can become clogged and ineffective, restricting airflow to the furnace and making it work harder to heat your home.

A dirty or damaged filter can also lead to a build-up of dangerous fumes in your home. Therefore, it’s best always to watch out for the signs of a failing furnace filter, which include:

  • The furnace is cycling on and off frequently.
  • There is little or no airflow coming from the vents.
  • The furnace is not igniting.
  • The furnace is making strange noises.

Read: 7 Best Heating Systems For Apartments

How To Fix?

If you think your furnace filter may be dirty or damaged, the best thing to do is replace it.

Tools needed:

  • New furnace filter: Try this Amazon Basics Merv 11 AC Furnace Air Filter (link to Amazon). It features a high MERV rating, meaning it will trap smaller airborne particles than a standard filter. Because of that, you can count on it to do a better job at protecting your furnace.
  • Screwdriver.

Here are the steps you’ll need to take:

  1. Turn off the power to your furnace at the breaker box.
  2. Remove the access panel to the blower compartment.
  3. Locate the furnace filter and remove it.
  4. Install a new filter in the same direction as the arrow on the frame.
  5. Reattach the access panel and turn on the power to your furnace.

Here’s a quick video demo of how to change a furnace filter:

Note: Ensure you read your heating system’s manual to ensure the replacement parts you’re buying are compatible with your system.

3. The Furnace Is Not Getting Enough Power

If your furnace isn’t getting enough power, it may not turn on or operate properly. That can result from:

  • A tripped circuit breaker or a blown fuse.
  • Incorrect wiring.
  • A faulty motor.

How To Fix

If you suspect your furnace is not getting enough power, here are a few things you can check:

  1. First, check your furnace’s circuit breaker or fuse. Reset or replace the fuse if it has been tripped or blown.
  2. Next, check the wiring to your furnace. Make sure all the connections are tight and that there is no damage to the wires.
  3. Finally, check the motor. If it is defective, replace it.

4. The Pilot Light Is Out

The pilot light is responsible for igniting the burner in your furnace. If this light goes out, the furnace will not be able to heat your home.

The pilot light may go out due to several factors, such as:

  • A draft in the furnace.
  • Dirty pilot jets.
  • A faulty thermocouple.

Read: Why Does My Central Air Have Two Filters?

How To Fix?

If your pilot light has gone out, here are a few things you can try to do to relight it:

  1. First, ensure all the gas valves to your furnace are turned on.
  2. Next, locate the pilot light assembly and clean any dirt or debris blocking the pilot light opening.
  3. Use a long-handled lighter to relight the pilot light. If the pilot light doesn’t stay lit, you may need to replace the thermocouple.

Here’s a video demo of how to fix a furnace pilot light:

5. The Heat Exchanger Is Cracked

The heat exchanger transfers heat from the combustion chamber to the air that is circulated by the HVAC system. If this component cracks, it can stop the system from working and leak deadly carbon monoxide gas into your home.

A cracked heat exchanger is often the result of:

  • Physical damage to the furnace.
  • Corrosion due to moisture.
  • Thermal stress due to frequent cycling.

The following video describes the signs of a damaged heat exchanger in detail:

How To Fix?

If you think your heat exchanger may be cracked, it’s crucial to have a professional inspect and replace it as soon as possible. For the best results, ask them to check your furnace for any other damage that may have occurred.

However, if you choose the DIY route, be sure to watch the following video for a detailed tutorial:

Pro Tip: In addition to replacing the heat exchanger, install a carbon monoxide detector in your home to help keep your family safe.

6. The Blower Motor Is Worn Out

The blower motor is the component that circulates the air through your furnace and into your home. For the furnace to work correctly, this motor must be in good working condition.

However, like other parts, the blower motor can wear out over time. When that happens, the furnace may fail to heat your home or may not work at all.

The tell-tale signs of a failing blower motor are:

  • The furnace is not blowing any air.
  • The furnace is blowing less air than usual.
  • The furnace is making strange noises.

Read: Is Ductless Heating Cheaper Than Gas?

How to Fix?

If you think your blower motor is worn out, you’ll need to contact a furnace repair technician. They will be able to diagnose the problem and make the necessary repairs.

Besides, calling a professional is always the best course of action when dealing with complicated or delicate furnace repairs.

They have the knowledge and experience to troubleshoot and repair any issue quickly and efficiently.

7. The Ignitor Is Dirty or Damaged

The ignitor is the component that ignites the gas in your furnace. The crucial part is usually made of ceramic and glows red hot when the furnace is turned on.

If the ignitor is dirty or damaged, the gas will not light, and the furnace will not heat your home.

Dirty ignitors are usually the result of a build-up of dirt and dust. Over time, this debris can prevent the ignitor from functioning correctly.

Damaged ignitors, on the other hand, usually need to be replaced.

Read: What Is The Most Efficient Heating And Cooling System

How To Fix?

If you think your ignitor is the problem, you’ll need to replace it. Here are the steps:

  1. Turn off the power to your furnace at the breaker box.
  2. Locate the ignitor and remove it from the furnace.
  3. Take the old ignitor with you to a hardware store or HVAC supply store so you can find an exact replacement.
  4. Install the new ignitor and reassemble the furnace.
  5. Turn on the power to the furnace and test it to ensure it’s working correctly.

Here’s a video that shows how to replace an ignitor:

Final Thoughts

There are several reasons why your central heating might not be working. The most common culprits are dirty or damaged parts, lack of power, or a pilot light that has gone out.

If you’re having trouble heating your home, check all these components before calling a professional. With some troubleshooting, you should be able to get your furnace up and running in no time. However, if you’re still having trouble, contact a furnace repair technician for help.