The heat exchanger is one of the largest and most important components of your home furnace. It converts the by-products of combustion such as flue gas into heat for your home. A properly maintained heat exchanger can usually last as long as the furnace itself, but it does occasionally need to be replaced. Routine wear and tear on the exchanger can result in stress fractures and small openings, and the resulting release of carbon monoxide (CO) fumes poses serious health risks for you and your family. Here’s a quick look at how heat exchangers work, as well as some frequently asked questions.
How Does a Heat Exchanger Work?
Your heat exchanger is composed of metal shells and elements that get heated up by flue gas. Your furnace burns natural gas or propane and creates combustion and heat. The flue gas is a by-product of combustion, and it travels through the heat exchanger on its way to the furnace’s exhaust outlet. Your furnace blows and circulates air over the exterior of the heat exchanger, and the heated air is then pushed through your ventilation system and ducts.
What Are Primary and Secondary Heat Exchangers?
Forced-air furnaces will have either one or two heat exchangers. The primary exchanger contains the hottest flue gas found closest to the burners. Furnaces that are 70-80% efficient will typically only have one heat exchanger. The primary exchanger is constantly subjected to flames and extreme heat, and the subsequent stress can lead to cracks and leaks.
New high-efficiency furnaces are over 90% efficient and they also include a secondary heat exchanger. The exhaust and flue gas passes from the primary heat exchanger and travels into a secondary heat exchanger. In the secondary exchanger, additional heat is released from the flue gas and water vapor also begins to form. The condensation process leads to an exothermic release of latent heat, resulting in an even higher efficiency level. High-efficiency furnaces are sometimes also conventionally known as condensing furnaces. The secondary heat exchangers found in high-efficiency furnaces are typically made from either stainless steel or a coated steel alloy that can withstand heat, moisture and even acid.
Can I Troubleshoot Service Issues Myself?
Even if you’re extremely handy, you should never attempt furnace repairs on your own. It’s also almost impossible to know if you have any problems with your heat exchanger unless you test for CO or perform a direct inspection. When you schedule a professional service call, the technician can perform a visual inspection and a combustion analysis/CO test. A licensed technician has the proper testing equipment for the CO test and the experience to notice problems during a visual inspection.
Your utility company adds a scent to natural gas so that you can smell a gas leak, and you should already know to leave your home immediately and call your utility provider. Unfortunately, Carbon Monoxide is completely odorless. Even very small levels of carbon monoxide are dangerous for both your family and your pets, so be sure to mount CO detectors in multiple locations and replace the batteries at least every six months. You should also occasionally turn the furnace completely off and make sure that your chimney and exhaust pipes are unobstructed and free from any blockage. A damaged exhaust pipe can also be a serious safety issue, even if the damage appears cosmetic. If you see any damage or blockage, be sure to contact a professional right away.
What Can I Expect During a Service Appointment?
Some furnace damage is easy to spot, even with an untrained eye. But we need the ability to peek inside in order to perform a thorough inspection. Instead of disassembling any components of your furnace, we utilize a special camera with a flexible shaft that can see deep into the unit. This enables us to locate internal issues in furnace heat exchangers that would otherwise not be seen from the outside. The combustion analysis and CO test require specialty tools but don’t usually require getting into otherwise inaccessible areas of your furnace. Your annual maintenance visit is a great way to prolong your furnace’s life and improve its efficiency.
Our licensed and bonded technicians are always a phone call away when you need quality HVAC or plumbing services in and around Stroudsburg. Contact R.J. Groner Inc. today for professional furnace services or if you would like a quote on furnace installation.
