Your furnace may be prone to many faults during its lifetime. One of the components that can cause inefficiencies and safety concerns is the heat exchanger. But what does it do, and why is it important? Here’s is an outline of what you need to know about a gas furnace heat exchanger.
What Is a Heat Exchanger?
The purpose of a heat exchanger is to transfer heat from the combustion chamber to the exterior of the HVAC system. When you switch on the furnace, it will ignite the gas. The system will send the hot gases from the combustion chamber through the heat exchanger.
Your furnace then pulls cold air from your home and passes it through the heat exchanger. The air becomes warm as it goes through the metal plates of the heat exchanger. The system will then distribute the warm air through the ducts to different parts of the building.
On the other hand, the combustion gases are blown out from the heat exchanger to the vent outside. Some systems have two heat exchangers that can absorb heat from exhaust gases.
Furnaces with two heat exchangers are commonly referred to as condensing furnaces since they produce condensation. They can attain efficiency ratings of up to 98%.
Why Are Heat Exchangers Important?
A heat exchanger is an efficient and safe way to transfer heat from combustion gases to your home. The more efficient a heat exchanger, the less fuel your heating system will need. The design and materials of the component have to withstand the extreme temperatures from the furnace.
Additionally, the tubes allow heat to move concentrically in different directions to avoid cold and hot spots. The heat exchanger can expand with the rise in heat inside the chamber. The tube will often have kinks to enable it to accommodate high pressure without breaking or cracking.
A heat exchanger also facilitates the flow of gases into the chamber and out of the vents. It enhances safety by ensuring furnace fumes do not escape into your home.
However, when the heat exchanger cracks, your furnace may release toxic gases into the room. If you notice a rotten eggs odor, it could be a sign of gas leakage. Call a White Mechanical, Inc. technician to troubleshoot your system in Foothill Ranch.
Types of Heat Exchangers
There are different types of heat exchangers suitable for varying applications. The three designs you’ll find in residential furnaces are tubular, clamshell, and serpentine heat exchangers.
Tubular heat exchangers consist of U- or S-shaped pipes. The shape of the tube’s curve makes for a robust assembly that can withstand high pressures and heat. stronger
The tubular design features continuous pipes with no gaskets or welding. The tubular type may also include double metal plates to prevent cross-contamination when there is a leak.
The other type is the clamshell heat exchanger prevalent in older furnaces. They have a set of metallic sheets with tubular channels for the gases to pass. Their advantage is they can handle the high temperatures in older furnaces.
However, the clamshell design tends to deteriorate where the tubes narrow. Since pressure is higher, they rupture and create an opening for the gases to escape.
Serpentine heat exchanger involves pressing parts against each other in one assembly. They are more compact and are suitable for smaller, modern furnace models. The assembly eliminates the need for manifold, making them easy to repair and more reliable. Serpentine heat exchangers are versatile and may be configured as evaporators or condensers for heating systems.
Condensing Furnaces and Two-Stage Heat Exchangers
The principal feature of a condensing furnace is a two-stage heat exchanger. Just like with conventional heating systems, they pull air through the filter and into the combustion chamber. The cold air absorbs heat through the first heat exchanger.
But instead of expelling the exhaust gases outdoors, the gas passes through a second heat exchanger. Since the exhaust fumes are still hot, the heat is absorbed and transferred to the cold air from the house. As the gases cool down, it generates moisture in the form of condensation.
Because the secondary heat exchanger creates condensation, it must be more resistant to corrosion than the primary one. The tubes may also have dimples or fins to ensure optimum heat transfer.
When temperatures in the second stage drop below 60 degrees, the moisture can damage your heat exchanger. Corrosion can increase the risk of cracking, which may allow gasses to escape.
Inefficiencies caused by rust can force temperatures to drop significantly. If you see signs of corrosion on the furnace, you may want to schedule a service for inspections. White Mechanical, Inc.‘s fully licensed and professional team can troubleshoot your heating system for your safety in Foothill Ranch.
Condensing furnaces have a sealed combustion compartment that draws air for combustion from the outdoors. The chamber prevents heat and toxic gases from escaping, offering higher levels of safety. However, the design may vary depending on the model and application.
What Causes Heat Exchangers to Fail?
Exposure to high temperatures and pressures can cause the metal plates to break down. The heat exchanger’s chamber will develop cracks, and joint connections may snap after years of operation.
Leaks from the heat exchanger are unsafe and can contribute to indoor air pollution. Carbon monoxide is one of the hazardous gases that can get into your home. It is odorless and colorless, which makes it difficult to detect without a sensor.
Additionally, layers of rust can limit heat transfer through the exchanger. As a result, your furnace will run continuously to meet the heat load of your home. The decrease in efficiency will strain your system, and the heat exchanger may develop more cracks or fail altogether.
Airflow obstruction is a common factor that leads to heat exchanger failure. Excessive heat within the heat exchanger’s chamber cracks the metal plates.
Change or replace your filter once a month. Ensure the filter matches the requirements of your forced air furnace to avoid airflow issues. You can consult White Mechanical, Inc. for dependable indoor air quality solutions in Foothill Ranch.
What to Do When You Have a Faulty Heat Exchanger
You can confirm if your heat exchanger is faulty by conducting a visual examination. You can use a flashlight and mirror to look for corrosion, cracks, or deterioration. If you spot signs of wear and tear, you should call a technician for repairs.
Technicians will use cutting-edge tools to detect corrosion and cracks at their earliest stages of development. The process will also involve testing for toxic gases to determine if your furnace has other leakages. The technician will troubleshoot the vent for blockages and check the pilot and burner for faults.
If your heat exchanger is faulty, you will often have to replace it. The component must operate within the manufactures parameters for safety. Therefore, welding the exchanger may compromise its performance, shortening the lifespan of your system.
White Mechanical, Inc. has 17 years of industry experience offering heating and cooling services in Foothill Ranch. As the recipient of 2020 The Best of Home Advisor, we are committed to maintaining our high service standards. We are a Lennox Premier Dealer, but we can handle virtually all brands of heating equipment. You can rely on our team for thermostats, air purification systems and other high-quality heating and air conditioning products. We also repair and maintain HVAC equipment of all types. Call our professional staff today and experience our award-winning service.
