Furnace Not Igniting – 4 Common Causes

Gas furnaces have been proven as one of the most reliable heating equipment in our house for years even decades. It is almost impossible to find any more reliable devices that can replace a gas furnace as the main heating device in our house. However, that doesn’t mean that this reliable heating device does not have some deficiencies.

Despite of its reliability, a gas furnace also has its own weak spot, just like any other mechanical appliance. There are many kinds of mechanical issue that may emerge to a gas furnace. One of the kinds is when a gas furnace fails to ignite and be turned on. This issue is arguably the most common issue that every gas furnace has.

In some occasions, a gas furnace can even blowing cold air, which can be frustrating especially when you really need to warm you house. When that happens to your gas furnace, you do not need to worry. This is not the end of your gas furnace and the issue is totally solvable as long as you do to job right. Therefore, here are some useful guides that may help you to when your gas furnace fails to ignite.

Furnace Ignition Failure Easy Troubleshooting

Whenever you experience any mechanical troubleshooting, there are only two options you need to do; solve it by yourself or simply call the experts to solve it. In this case, a gas furnace troubleshooting is not always complicated to solve. There are some simple instructions that anyone can follow, even by those who are lack of experience in mechanical.

1. First Things First – Check Your Gas Supply

The very first thing you need to do to figure out why your gas furnace does not ignite is to make sure that your gas furnace has the gas supply. There are two ways to work this step.

Natural Gas Users

This step actually is not recommended if you apply a city gas line since it is too risky and dangerous to do the natural gas supply to your heater by yourself. In case you apply a city gas line, it is better for you to call a professional technician to prevent any risks. Then if you feel there is any gas smell around your gas furnace when it is turned, there is a good possibility that the trouble is not about the gas supply.

LP or Propane Gas Users

In case you apply liquid propane for your furnace, it will be easier for you to figure out whether your furnace already gets enough gas supply or not. First thing you need to do is go to outside your house then identify where the gas storage tank is located. There will be vaulted area on the top center of the gas storage tank. That is also where the fill valve and the gas pressure gauge are located.

If the gas pressure gauge shows 25 or more, then there is no problem with your furnace. Otherwise, you will need to call the gas company to fill it up because that is the reason why your furnace is not igniting. This is where you need to call professionals because you cannot fill the furnace up by yourself.

2. Check Your Air Filters

This is the step that you really need to do to prevent any charge by calling professionals to do the job. If the air in your furnace system is not flowing, it will not produce the warm air that your house needs. It may be the reason why your furnace is not igniting. At any other times, there is also a possibility that the air is restricted, blocking its way to your furnace igniter.

The restriction is sometimes caused by the dirty filter, causing the air blocked and distracts the igniting. That is why you need you to check your air filter routinely to prevent your furnace from ignition failure. Checking them routinely will save you some money in the future. It also recommended that you change your air filters at least once in a year.

3. Ignition Source

There are two steps required to make your furnace reach its peak ignition by processing the gas air mixture. The most conventional step is known as a pilot light, which was already applied since furnace was invented. For the last 30 years, this kind of system is mostly known as electronic ignition system, which has replaced the pilot light system. These systems have to do the work well, unless your furnace will not ignite.

Pilot Light

The concept of this system is to keep a small flame inside your furnace keep burning. The flame will not consume much gas since it is so small. If you check at the bottom part of the furnace, you will find a tray where the flame is burning. The pilot light system is located on one side of the tray, normally slightly above it.
Look under the furnace to check whether it is lit or not. In case it is not lit, you may need to use a long lighter to light it again carefully. If it still does not work, you may have a bigger trouble and it is suggested to call the professionals.

Electronic Furnace Ignition

Since this system is applied to replace the pilot light, electronic furnace igniters will make your furnace safer since you do not need that small flame in a furnace that is required in the pilot light system. This system is normally located in the same position as the pilot light system is located. The electronic furnace igniters are made of featherweight metal mixture that will get extremely hot once an electric flow goes through it. This process will ignite the gas mixture that goes to the furnace.

4. Thermostat

When you move the thermostat in the gas furnace to higher setting when it is turned on, some things will happen to trigger the furnace ignition. You may hear some sounds of the system’s fan that will accommodate the air to start the burning mechanism. You may also hear twirl sound of the ignition gas. After some moments, the gas furnace will start flowing hot air to your rooms house through the vents inside your house.

This process will not be happening if something wrong is found in the thermostat. So, how can you know that your thermostat is faulty? It is very easy to find out because a faulty or defective thermostat will not produce any sounds described before, since the thermostat does not communicate at all with the furnace once it is turned on. A broken thermostat will not produce any sounds and it will be just silence around the gas furnace.