Signs You Need To Have Your Furnace Heat Exchanger Repaired Or Replaced

2 February 2022
 Categories: , Blog

Every furnace has a heat exchanger. This part contains the flame, transferring heat from that flame to the air that later gets circulated through your home. Heat exchangers are essential to a furnace's proper function, but they are also one of the most common parts to break and require replacement or repairs. So, what are the signs you need to call the HVAC repair company about your heat exchanger?


Soot is a black, somewhat sticky substance that is released when a fuel is not burning at a hot enough temperature. You may see it on the outside of your furnace, or even on the walls around your furnace. If you do, this is an almost sure sign that your heat exchanger is cracked or broken. The broken heat exchanger will alter the temperature at which the gas, propane, or oil burns, which leads to soot formation.

Banging Noises

There are a number of reasons why a furnace may make banging noises. It's important to pay attention to when the banging is happening. If there is one big bang each time the furnace kicks on, this is usually an indication that the heat exchanger has broken. The bang is actually a buildup of fuel all igniting at once. This can be dangerous if not addressed, which is why calling for repairs is so important.

Carbon Monoxide Presence

Carbon monoxide is an odorless, invisible gas that is produced when fuel is burned. It can cause headaches, nausea, and even death. When everything is functioning properly, CO should be vented out of your home as your furnace operates. But if you have a cracked heat exchanger, carbon monoxide may be able to leak into your home through the crack. If your CO alarm ever goes off, get out of the house and call a heating repair company ASAP. You probably have a heat exchanger problem that needs to be addressed before it's safe to breathe the air in your home again. 

Odd Odors

People in homes with broken heat exchangers often note that their home has an off, chemical-like odor that becomes more obvious when the furnace is on. If you notice a smell that's unfamiliar, strange, or hard to place, play it safe and call your furnace repair company.

Sometimes a heater repair technician will fix a heat exchanger, and other times, they'll replace it entirely. It depends on the nature of the damage and the age of your furnace. If you suspect there may be a problem with your heat exchanger, don't delay seeking repairs.