My Furnace Won’t Ignite

Homeowner’s Checklist: Before You Call for Heating Repair

It can be a nightmare to suddenly find yourself dealing with a broken furnace. Hopefully you are not discovering this in the middle of a freezing Colorado winter. DALCO Heating & Air Conditioning recommend that all Denver homeowners do a test run of their furnace well before winter hits. That way any problems can be detected and handled well in time before you need your heating system to work.

The first cold snap to hit the Denver area doesn’t just mean you’re dealing with a furnace problem at a time you need heat, but you are also now faced with the difficulty of getting a professional heating technician to come to your home. It’s at this time of the cold season when DALCO Heating and Air Conditioning as well as other HVAC companies across Denver are getting flooded with furnace repair calls and so may not be able to get to your home as soon as you would like.

Fortunately, if you find that the cause of your broken furnace has to do with it not igniting, there are several things you can do as a homeowner that may actually fix the problem, allowing you to save time, money and prevent spending even one night in a very cold house.

Understanding furnace ignition sources

How to Light Your Furnace

There are 2 main ways that most furnaces ignite and so you first need to identify which of these ignition sources applies to your furnace.

Pilot Light

furnace Pilot light icon

This is the oldest way that furnaces have been made to light. A pilot light is a small flame that is constantly burning inside your furnace. Look at the bottom of your furnace for a tray where the burners are and you will see a pilot light, usually located to one side and just slightly above the burners tray. You will need to supply fire to this pilot light, either with a long match or long lighter. Make sure the control knob is set on pilot.

6 Steps: How to Light a Pilot Light

  1. Before even addressing the furnace itself, turn your thermostat down very low so that the heater won’t come on immediately when you light your pilot light.
  2. Turn the control knob so that it set on pilot. If it was already in the on position, turn it to off and wait 5 minutes in order to clear out any gas. SAFETY WARNING: If after waiting the 5 minutes you smell gas in that area, that could mean you have a gas leak somewhere. If so, do not attempt to light your furnace yourself. Contact us to come out and ensure your lines are safe for it to be relit.
  3. Turn the knob to pilot.
  4. Push in the control knob. You may be able to hear the sound of gas going through the pipe. With that being pressed, use either a long lit match or a long lighter to put a flame under the gas port of the pilot. If you see a small flame now burning from the pilot light, continue pressing the control knob for a full minute. If this is the first time you are lighting your heater for the first time of the season, it may take several minutes to get it lit. The gas that is needed to ignite the pilot light has to travel the length of the gas line. The longer your gas line is, the longer it will likely take before your pilot light will ignite.
  5. Slowly release the knob. Ideally your pilot light is still burning. Now you turn the knob to the on position.
  6. Turn your thermostat up. You should now see more flames burning in your furnace tray.

Electric Furnace Ignition

Electric furnace component icon

This is the most common type of ignition source for modern furnaces. An electric ignition is considered the safer of the two as it doesn’t require any amount of gas to ignite like a pilot light does. They are made of a metal alloy that heats up when an electric current goes through it. This heat ignites the gas/air mixture that is coming into your furnace. You can’t relight an electric ignition as you would a pilot light. Instead, you will be checking to see if the electric ignition is lighting up in order to help diagnose the problem, which may be to replace the electric ignition.

4 Steps: How to Know if an Electric Ignition is Burnt Out

  1. Turn the power on to your furnace.
  2. Look into your furnace to see if your ignitor is glowing. They are typically located in the same place as a pilot light (see above Pilot Light section).
  3. You will hear a click when the gas valve opens, sending gas through the area with the electric ignitor. You may hear the sound of gas hissing. If there is still no flames coming up from your electric ignitor, that is a good indication that your ignitor is burnt out.
  4. If you are able to get a good visual of the ignitor, spotting a crack in it is also an indication that your ignitor is burnt out or there is some problem with the power in supplying electricity to your furnace ignitor.

Replacing an electric ignitor on a furnace is sometimes something homeowners can do themselves, at least those who feel confident enough handling furnace repair that requires more than basic maintenance skills. Beyond just your level of heating repair abilities, you do need to consider what type of furnace you are dealing with. Many modern, high-efficiency furnace models have an electric ignition tucked inside the unit that makes it difficult to access.

Troubleshooting why a furnace won’t ignite infographic

Troubleshooting: 4 Reasons Why a Furnace Won’t Ignite

If you’ve taken the necessary steps to ignite your furnace and it still won’t light, that could mean your furnace ignition is broken and needs to be replaced. However, there are several different causes that could be keeping your furnace from lighting that a homeowner can check. If it’s one of these lesser issues, the work and cost of getting your heating system back and running could be easier and cheaper than needing a repair from a heating technician.

Here is a list of 4 items that homeowners can check before they call and pay for a service call. How much mechanical know-how you have may determine how many of these steps you feel comfortable doing yourself. These steps are listed in order of the most basic and easiest troubleshooting steps for a furnace that won’t ignite to the ones that may be just a bit too difficult or intimidating for those who don’t feel comfortable handling the mechanics of your heating system.

  1. Checking Thermostat to see if that fixes a furnace problemCheck your thermostat
    Make sure your thermostat is set to heat, and that the temperature it is set at is above the current ambient temperature. Set the desired temperature up a few degrees. If you don’t feel heat coming from your vents shortly after doing this, you can eliminate this as the problem.
  2. Dirty filter coming out of a broken furnaceCheck your air filter
    It’s possible that a very dirty air filter could be preventing your furnace light from igniting. If the proper air flow isn’t happening, this could be restricting the pilot light from getting or staying lit.
  3. Check the circuit breaker
    The circuit to your furnace may have gotten tripped. If so, turn it off for a few minutes then reset it. Watch to see if it trips again. If so, you will need an HVAC technician to investigate what’s causing this problem. Request service from DALCO Heating & Air Conditioning and we will send a heating technician to your home for the repair your furnace needs.
  4. Check the gas line
    There is a switch inside or near the furnace that turns the furnace on and off. Make sure that it is set to the on position. Also look for the gas valve and make sure it is not shut. If you have other gas burning appliances, you should check to see if those are operating to verify whether the gas is on.

Furnace Ignites but Heat Still Not Coming on?

Well the good news is you eliminated one problem. But the bad news is there are still a variety of other issues that could be the one causing your furnace to not work. Fortunately, there are more troubleshooting steps you can do with other components of your heating system, and many fixes you can do yourself.

Let the Denver heating repair experts at DALCO Heating & Air Conditioning know what your particular problem is. We made it easy to reach out to our HVAC team with an online Ask-A-Tech form.

Ask A Tech to get help on your HVAC problems

One Easy Way to Avoid a Big Furnace Problem

As we mentioned at the beginning, finding out your furnace isn’t working in the dead of a Denver winter is the worst time. This can easily be prevented, and the first step in making that happen takes only a few seconds and you can do it RIGHT NOW!

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Put a reminder on your phone to turn on your heater on a full month before you expect to need it. For many of us in the Denver area, that date might be in September.

This advice applies to your air conditioner as well. So, while you have your calendar open, go ahead and schedule a reminder to turn your air conditioner on sometime in the spring.

If you notice any problems with your furnace or other heating system before the worst of the season strikes, you can request service with DALCO Heating & Air Conditioning to have any problem resolved before you and your family are in need of your furnace or air conditioner working. We have a large team of experienced furnace technicians and service the greater Denver area. Be sure to check out our page of deals and discounts to see if you can save money on the service that you need.

Call us at 303-979-7541

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