Your furnace is an essential part of your home's heating system that keeps it warm during cold seasons. It does this by generating heat from a fuel source and distributing it around the house through a duct system.

The furnace has several components, which work together to make it effective. If any of the parts break down or start malfunctioning, the chances are that your furnace won't fire up and produce any heat. That's why you need to diagnose the problem and fix it as soon as possible. If your furnace clicks on but is not igniting, there are several potential causes for this issue. While some are relatively simple to repair, others may require a professional furnace repair technician to find and address the exact problem. 

In this article, we've covered five of the most common reasons why your furnace might be clicking on but not igniting, as well as what you can do to fix it.

1.  The Pilot Light Went Out

The most common reason gas furnaces won't ignite is because of a problem with the pilot light. So, the very first thing you need to do is check and see if the pilot light is still lit. When your furnace's pilot light goes out, you may be able to get the fire started again by pressing the "reset" button or turning off the furnace and turning it back on. Assuming your furnace has a pilot light, you can relight it by following this procedure:

• Turn off the furnace's gas supply.
• Locate the pilot assembly for your furnace and turn it to "pilot."
• Push and pin down the reset button on the pilot assembly.
• Light a match and hold it over the opening in the pilot assembly until there is a steady flame.
• Release the reset button and keep holding the match to the opening while you continue to hold down the reset button for another minute or so.
• Turn on the gas supply and then turn your furnace back on.

However, if it still doesn't work, getting your furnace unit serviced and repaired by a professional furnace repair technician in Walnut Creek, CA, would be the best idea.

2.  Faulty or Broken Thermostat 

If you have a gas-fueled furnace that doesn't ignite, you should check your thermostat settings. Ensure that your thermostat or thermocouple is set to "heat," and double-check that the temperature setting is high enough for the heater to turn on. Also, turn the fan setting off if it's currently on "auto." However, if that doesn't work, and you still fail to fire up your furnace, check the thermocouple to see if it's bad or damaged.

The thermocouple is a safety device that tells the gas valve to stay open until it detects enough heat from the pilot flame. If this part fails, it won't tell the gas valve to stay open, and thus no gas will come out. In that case, you should schedule a furnace repair service in Walnut Creek, CA, to have a qualified HVAC expert replace the faulty component and fix your furnace.

3.  A dirty flame sensor

The flame sensor is a part of your furnace that detects whether or not the gas has ignited. When it senses a flame, it sends signals to other parts of the furnace to turn off and stop releasing gas into the system. If it doesn't sense a flame, it will keep releasing gas into the system until it does. If your flame sensor is dirty, this can prevent it from detecting the flame and cause your furnace to keep trying to ignite the gas without success. You will know this is the case if you see sparks but no ignition.

Before you begin working on it:

• Turn off your furnace and wait for about 5 minutes for any residual gas to dissipate.
• Clean the sensor with a rag dipped in warm water and vinegar or rubbing alcohol.
• Keep doing this until all of the dirt is removed from both sides of the flame sensor.

4.  Your Energy Saver Switch Is On

Many furnaces have an "energy saver" switch that turns off the fan after a set period of time. If your energy saver switch is on, this will automatically turn off your furnace after five minutes of no activity if your furnace has a continuously running blower fan or 15 minutes if it does not have a continuously running blower fan. This feature can be overridden by simply switching off the energy saver switch. In case your furnace still fails to light up, it would be in your best interest to hire a furnace repair company in Walnut Creek to get your system fixed.

5.  Check Your Air Filter

When was the last time that you checked or replaced the air filter? Your air filter is the first line of defense against outside dust, dirt, and debris. A clogged or dirty filter can cause all sorts of problems in a furnace — and even disable it altogether. A dirty air filter restricts airflow and prevents proper combustion in the furnace, which could be up to 15% less when your air filter is clogged. So, if your furnace does not light, you need to check for any blockage in the air filter and then replace it with a new one.

A number of internal issues can cause your furnace not to ignite, including clogged burners or a broken fan limit switch. These problems are best left to professionals, like Right Now Air & Solar. If you have a furnace and live near Walnut Creek, Fairfield, or Vacaville and need furnace repair, contact us at (707) 447-3999 today! Our HVAC squad can help you with any of your heating and cooling needs.