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Cracked Heat Exchanger: How a Furnace Might Become Dangerous

Last week we wrote a post about how to protect your family from carbon monoxide, which is a concern that any home that uses natural gas may have.

In this week’s post, we’re going to examine one of the ways that a gas furnace can malfunction and create a CO poisoning hazard in the first place: a cracked heat exchanger.

What the Heat Exchanger Is

A heat exchanger is an essential part of any natural gas furnace. It is the component that is responsible for transferring the heat of the combustion gases that come from the burners to the air that moves into the ventilation system.

The standard heat exchanger is a metal chamber, often shaped like a clamshell, which is housed above the burner assembly. The combustion gases enter the heat exchanger and their high temperature heats up the metal walls. The blower fan sends air around the exchanger, where it picks up the heat from the exchanger’s outer walls. The leftover combustion gases (such as CO) in the heat exchanger are vented through a flue and safely out of a home.

The Danger of Heat Exchanger Cracks

A heat exchanger expands and contracts as its temperature rises and drops. This strain is normally not a problem, but if there are weak spots on the metal because of corrosion, it can cause gaps to open up when combustion gas is in the exchanger. And when that happens, the toxic gases can escape and go right into the air that’s circulated through the living spaces.

How to Know You Have a Cracked Heat Exchanger

First, watch out for any indication of corrosion on the furnace. Corrosion occurs because of the interaction of vapor in the combustion gas with metal, and it’s often a sign of a furnace that’s too old and may need a replacement. Also listen for the sound of clicking after the blower fan turns off, which is a warning of cracks along the exchanger. And at the first signs of CO levels increasing in your house—along with getting out of your house—call for repairs to check on the furnace.

When you need expert furnace repair in Rolesville, NC, call on Comfort Master Heating & Air Conditioning, Inc. We’re here for you 24 hours a day, 7 days a week.

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