Gas pressure If this pressure is too little, condensation could collect inside the heat exchanger, which can lead to corrosion. However, if pressure is too high, this may lead to extremely high temperatures inside the unit, even forming soot on the walls of a heat exchanger, which can combust.
Yard debris, animal nests and other obstructions can block the furnace flue, restricting oxygen. This leads to soot buildup and bad ventilation, decreasing efficiency and increasing the risk of flame rollout. Flame rollout is when fire gets out of the heat exchanger and burns the parts inside your furnace.
If the flame sensor fails, your furnace may not be able to start or may shut down shortly after starting. Common causes of flame sensor failure include corrosion, dirt buildup, or a broken wire. The gas valve controls the flow of gas to the furnace. If the gas valve fails, your furnace won't be able to produce heat.
A furnace explosion is usually the result of ignition and instantaneous combustion of highly flammable gas, vapor, or dust that has accumulated in a boiler. The effect of the force from the explosion is often much greater than the boiler combustion chamber can withstand.
Although it is possible for a gas furnace to either catch fire or explode, it's highly unlikely. If there is a danger of this happening, the furnace will usually simply shut off—as it's designed to. Regular maintenance will further reduce this already unlikely event.
Your furnace will need to work harder, the blower motor will run for extended periods of time, and this could cause it to overheat. The devastating effect of internal temperatures climbing is that components could catch fire.
Issues with the gas line, like a clog, can also lead to an instant furnace ignition failure. That problem is simple since any obstruction in the gas valve or gas supply will prevent enough natural gas from reaching the ignition. That means the system won't trigger the combustion process or generate heat.
Check and Change Your Clogged Filter
This is a simple but essential part of furnace maintenance. One of the most common reasons to have a furnace not working is a clogged filter. It also happens to be the easiest maintenance chore.
As stated by the National Fire Protection Association (NFPA), heating systems like furnaces are a major cause of home fires, contributing to almost 50,000 blazes, 500 civilian deaths and more than $1 billion in significant property damage every year.
Replacing a furnace is a labour-intensive undertaking and is pretty difficult. There are a large variety of factors that need to be considered and accounted for. It is never recommended to replace a furnace yourself as the appliance is a major investment and should be handled by professionals.
Portable heaters can cause fires if they are placed too close to combustible materials, such as drapes, furniture or bedding, so make sure to place them at least three feet away from these materials.
A gas furnace should have a vibrant or bright blue flame. When you see a weak and wavy or flickering flame, this indicates gas is not being completely burned. Pilot light color changes are another indicator that carbon monoxide is not venting away from the system safely.
If you've ever made a campfire, the process of starting a fire in a furnace is similar. Start with some kindling (e.g., dry twigs, newspaper, etc.) and get a small fire going. Starting small allows your furnace's flue to warm up, which promotes a good draft and helps to alleviate creosote buildup.
If the ignition system fails, it may cause gas to build up in the furnace before igniting, resulting in a dangerous explosion or fire.
My gas furnace won't ignite.
Checking your thermostat is the best place to start. Make sure it's set to “heat” and that you've set the temperature higher than the current room temperature. If that doesn't resolve the problem, try switching your fan to “on” to force the furnace to start working.
Most likely, your furnace is making a clicking noise and not providing heat because your furnace's spark igniter is trying to ignite your pilot light or burners but is failing to do so. In other words, there's an ignition system malfunction that needs to be fixed. Otherwise, your furnace won't start.
The Average Furnace Lifespan
A well-maintained furnace can last at least 15 to 20 years, but completing annual maintenance and being diligent with repairs can extend its life even longer.
Your base homeowners policy will cover many types of damage to your furnace. An extra endorsement known as Equipment Breakdown Coverage (EBC) will give you additional coverage for certain types of mechanical or electrical failure.
For people taking a proactive approach, doing a furnace replacement during the “shoulder seasons” of spring and autumn may offer lower prices, shorter lead times, and a better selection of products and service appointment availability.
If you suddenly hear loud and strange sounds like squealing or grinding, these are symptoms of a bad furnace motor blower that can signal signs of motor bearing problems or a damaged belt in older belt-driven models. Repairs may be possible or it may be time to replace the blower motor entirely.
Replacing a furnace blower motor costs $560, on average. Depending on the size and type of motor, most people pay $300 to $900. The average blower motor replacement cost is $560, but the final price depends on labor fees, as well as the cost of the parts.
Electrical Burning Odor
Blower motors commonly overheat due to clogged air filters. Check yours, and if it's disgusting swap it out and let the blower motor cool off for a short time before turning the system back on. Under normal operating conditions, your system should shut itself off if it begins to overheat.