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.
Inadequate Gas Pressure
It also causes unwanted condensation within the heat exchanger, increasing the rate of corrosion. Conversely, high gas pressure can produce excessive heat in the furnace, which can cause the soot inside the heat exchanger to combust. Such fires can readily spread to other areas.
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.
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.
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.
Furnace Not Igniting Because of Incorrect Thermostat Setting
Make sure the thermostat is set to heating and that the temperature is set high enough to actually turn the furnace on. It may be set at too low of a temperature to activate the furnace.
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.
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.
Depending on the fuel source your furnace uses, shut off the main gas or oil supply lines, or flip the main electrical breaker to your home. Deprived of fuel, some furnace fires will just go out on their own. Use a fire extinguisher. If the fire is spreading, use a dry chemical fire extinguisher to control the blaze.
If the ignition system fails, it may cause gas to build up in the furnace before igniting, resulting in a dangerous explosion or fire.
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.
Dust on heating elements can produce a burning odor when the furnace starts up. Dampness or mold in the ductwork can cause a musty smell. A gas odor could indicate a leak, which is a serious safety concern. Overheated components or electrical issues can create a burnt smell.
Electric furnace installation tends to be the least expensive, ranging between $3,000 and $7,000, according to HomeAdvisor. Installing a natural gas furnace falls in the range of $3,800 to $10,000, and an oil furnace ranges $6,750 to $10,0000.
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.
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.
Miscalibrated thermostats that read the temperature in your home as either too hot or too cold can cause your heating system to turn off before your home reaches your preferred temperature or keep running long after it achieves the desired warmth. This may not mean you need a new thermostat.
The pilot light in a well-functioning furnace should be blue and vibrant. Pale or weak flames indicate a problem with the amount of gas burning. If your pilot light is wavy or flickering, the gas may not be thoroughly burning. This could indicate a leak, inefficiency, or another issue.
Take a Look at the Air Filter
Due to safety reasons, if a furnace's air filter has become clogged, the furnace will no longer ignite. So, if your furnace is failing to ignite, it's a good idea to check the air filter. If it looks clogged up, then this is probably the source of the problem.
Most residential furnaces are built pretty equal, some share the same parts. Put one in wrong and you'll get failed heat exchangers and blower motor problems from duct issues, pressure switch trips from incorrect venting/combustion air, sooting from incorrect setup/LP conversions, clogged coils from lack of maitenance.
As reported by the National Fire Protection Association (NFPA), heating systems like furnaces are a major factor of home fires, leading to almost 50,000 blazes, 500 civilian deaths and more than $1 billion in significant property damage each year.
If your furnace's problems continue, contact an HVAC expert. Also, if you notice discoloration when you check the pilot light, get professional help. If there are cold spots in your home, even though hot air is coming out of the air vents, the issue could be different from your furnace not working.