Don’t settle for ventilation problems with the furnace in your home in Centennial. Contact JC Mechanical for servicing today!
Winters in Colorado often include freezing temperatures and snowy weather, so many households rely on furnaces for warmth and comfort. If you use an oil or gas furnace, your heating system will include an exhaust pipe to release harmful gases. So what happens if your furnace exhaust is blocked?
At JC Mechanical, we offer expert furnace repair in Centennial, CO, and the surrounding areas at competitive rates. We pride ourselves in maintaining the highest caliber of furnace safety for all of our customers. Here, you can learn what happens with a blocked furnace exhaust and how you can prevent it.
What Is a Furnace Exhaust?
A gas or oil furnace will have a furnace exhaust system, which includes a flue to disperse fumes and gases. When you run your furnace, the oil or gas will blend with oxygen to create combustion and generate heat. The system’s blower fan disperses the heated air through the duct system.
Combustion exhaust is the byproduct of this process. It contains a mix of carbon monoxide and carbon dioxide, which the furnace flue expels from the home as a liquid vapor.
The flue can run from the furnace to a chimney. However, if one isn’t available, the flue will exit through the roof to disperse the unwanted gases. Most furnace exhaust systems have a screen or covering on the end of the flue to prevent blockages, but they can still develop over time.
What Happens if a Furnace Exhaust Has a Clog?
What happens if your furnace exhaust is blocked? A clogged flue will cause several problems including potentially dangerous situations.
First, the exhaust system needs to provide sufficient airflow to facilitate the combustion process. Without enough oxygen, the furnace will have an incomplete combustion, which would release potentially harmful partially combusted gas molecules into your home.
A flue obstruction will also prevent those gases from venting outdoors safely. Instead, they will go back into the house.
Carbon monoxide is one of the biggest gas appliance dangers and a consequence of having a flue blockage. It’s an odorless, colorless gas that can be lethal with prolonged exposure. With minimal exposure, the gas could cause serious health-related problems like:
- Headache
- Upset stomach
- Chest pain
- Confusion
- Weakness
- Dizziness
Reasons a Furnace Exhaust Gets Blocked
A furnace flue can develop obstructions for many reasons, even if the exterior vent has a protective screen. Clogs occur due to:
- Vent damage
- Corrosion
- Animals and nests
- Soot buildup
- Branches, leaves, and other debris
Common Blocked Exhaust Consequences
The threat of carbon monoxide poisoning isn’t the only reason to worry about a clogged gas furnace exhaust. The ventilation system will also affect your furnace’s performance and your comfort. A furnace shutdown is possible unless you contact an HVAC professional to regularly inspect and repair or clean your flue.
Below are the other problems you could experience if your furnace exhaust has a blockage.
No Hot Air from the Furnace
The most common sign of a furnace exhaust obstruction is a lack of hot air coming from the heating system. The flue disperses gas and ensures the furnace has enough airflow to allow the combustion process. With a clog, the flue won’t provide enough air to the furnace.
If the furnace doesn’t have enough moving air, there’s nothing to trigger the pressure switch connected to the inducer fan. The fan is what circulates air within the combustion chamber, so the furnace won’t produce heat unless all of its components work together.
The reason the pressure switch won’t turn on unless the inducer fan is circulating air is to prevent incomplete combustion from occurring. It’s a safety mechanism to keep dangerous partial combustion gases from seeping into your house.
Furnace Heats Up Before Quickly Shutting Down
Your furnace might work for a while before shutting down prematurely if your furnace exhaust has a clog. The process can repeat several times before the system gives up, leading to a permanent furnace shutdown.
This issue stems from the lack of airflow from the flue, causing the flames from the system’s burners to roll out of the combustion chamber and into another part of the furnace. This triggers the rollout switch, which will shut off the heating system to avoid additional problems.
A gas furnace may turn back on after tripping the rollout switch three or four more times before the system does a hard shutdown as a safety measure. If that happens, you’ll need to reset the furnace before running it again.
Unpleasant Odors
Your furnace shouldn’t produce unusual, unpleasant odors when it runs. At most, your furnace might have a dirty or smokey scent when you operate it for the first time of the season, but that will dissipate quickly.
However, combustion gases can generate a foul smell during the heat exchange process, but you shouldn’t notice with a fully functioning furnace and ventilation system. If the odor is noticeable, it’s likely due to a furnace flue blockage that’s causing combustion gases to get inside your house.
Hot Front Cover Panel
You might also notice the furnace’s front panel emitting more heat than usual if the furnace exhaust is blocked. For a complete combustion to occur, the flames from the burner must be in the combustion chamber. If there isn’t enough air to suck the flames into the proper location, the fire will roll out and heat other parts of the furnace, like the front panel.
Turn to JC Mechanical for Your Gas or Oil Furnace Needs
With over 30 years of industry experience, our team at JC Mechanical proudly offers comprehensive heating and cooling services. Whether you’re wondering what happens if your furnace exhaust is blocked or how furnace sizing impacts your home’s comfort, we have the skills, experience, and expertise to address all of your concerns.
As a top-rated family-owned HVAC company serving Centennial, Colorado, we also strive to exceed our customers’ expectations. Call (720) 740-6083 to get an appointment with us at JC Mechanical today.