Signs of a Damaged Furnace Heat Exchanger

A heat exchanger is an integral part of your furnace – it keeps the combustion chamber and the breathing air separate within the furnace.

Made of thin metal panels (and sometimes coils), a heat exchanger is designed to heat the air before it is distributed throughout the house. The metal panels or coils of the heat exchanger are heated up by the burners inside the unit. The blower then blows air over the heat exchanger, which heats it to a high temperature and then travels through the ducts to keep you toasty and warm.

When a heat exchanger becomes damaged, the combustion fumes and gases within the furnace mix with the clean air that's meant to be pumped into your home. As you can imagine, this is an incredibly serious and dangerous scenario. A damaged or cracked heat exchanger can end up pumping dangerous gases into your property.

Inspecting your heat exchanger regularly is essential to keep everything running safely and smoothly. If you find any cracks or damages to your heat exchanger, it's essential to get it fixed immediately.

What are the signs of a cracked heat exchanger?

Visible cracks – easily seen with infrared light, but a flashlight is good enough to see more noticeable cracks. Remember: just because you can't see a crack doesn't mean there isn't any damage
Evidence of soot buildup on the sides of the heat exchanger
A distinct odor, similar to paint thinner or vanish
Check the burner flames – they should be a blue consistent flame. If you see a yellow flame, it indicates more oxygen is present which could mean a crack in the heat exchanger
Medical issues in the family that disappear when you leave the house – headaches, nausea and eye irritation. This could be related to the carbon monoxide leaking from the heat exchanger

How to prevent damage to your furnace’s heat exchanger

The best way to prevent damage and a dangerous gas leak is regular inspection by a professional.

Have the furnace inspected annually and make sure to look for the many signs of a problem with your heat exchanger.

If you have a cracked heat exchanger, you have to take immediate action right away.

A cracked heat exchanger is an incredibly dangerous problem and it will need to be sorted immediately. A lot of the time it's actually more cost effective to replace the furnace than repair it, but this is a decision you need to talk through with your HVAC maintenance company.

Heat exchangers can be quite expensive, which is one of the reasons we created our unique Comfort Club Maintenance Membership.

When you join the Comfort Club, one of our qualified experts will assess your HVAC system and ensure it's working 100% correctly. If it’s not, we can help you with a variety of solutions and payment options to avoid any unexpected bills in the future.