What Is a Cracked Heat Exchanger and How Can it Be Repaired?

With proper maintenance, your furnace can potentially last multiple decades. When a furnace isn’t maintained, costly issues and repairs may arise, including a cracked heat exchanger.



A heat exchanger is a crucial part of your furnace that heats indoor air. If your furnace has become inefficient in the way it heats your home, a cracked heat exchanger may be the culprit. Although a cracked heat exchanger is a serious issue, it’s one that can be repaired.

Does the heat exchanger in your Arlington, TX home have cracks? Is your furnace underperforming compared to previous years? The heating repair specialists at Tom’s Mechanical are here to quickly identify and fix the issues you’re experiencing with your heating system.

What Is a Heat Exchanger?

A heat exchanger is one of the most important parts of a furnace. As the name implies, a heat exchanger is a device used to transfer thermal energy. Heat exchangers come in a variety of forms, but all rely on the transference of temperature via a gas or fluid. In the case of a furnace, fuel is burned to heat cool air and distribute it through your home via ducts.

Most heat exchangers in furnaces use conduction or convection for heat transfer. Radiators and radiant heating are examples of heating via radiation.

Causes of a Cracked Heat Exchanger

Heat exchangers can crack due to age and corrosion, poor installation or design, heat cycling and over-firing. Corrosion can occur when acids from combustion gases come in contact with the heat exchanger.

Improper installation can put stress on the heat exchanger, leading to cracks. Heat cycling, which is when the furnace turns on and off frequently, can also cause stress on the heat exchanger, leading to cracks. Over-firing, which is when the furnace burns too hot, can also cause cracks in a heat exchanger.

Other potential causes of a cracked heat exchanger include:

·       An oversized furnace can cause overheating and cracks in the heat exchanger

·       Poor or improper manufacturing of the unit

·       Dirty air filters can restrict air flow, causing your heat exchanger to overheat and develop stress cracks

Signs of a Cracked Heat Exchanger

The following signs are indicative of cracks in your furnace’s heat exchanger:

·       Visible cracks on the exterior of the heat exchanger

·       A foul smell emanating from the furnace

·       Higher energy bills

·       A yellow furnace flame which indicates something is malfunctioning inside the furnace

·       Dust or debris near vents

·       Soot has accumulated inside the furnace

What Are the Consequences of a Cracked Heat Exchanger?

A damaged heat exchanger can be dangerous to your health. A heat exchanger that has cracks or rust holes in it can release toxic fumes, including carbon monoxide, into the air. While a small crack is likely harmless, once it gets bigger and starts releasing even the smallest amount of carbon monoxide, it can harm you, your family and your pets.

If you feel nauseated, disoriented or unusually groggy but your symptoms subside when you leave your home, get emergency medical care and call a heater repair professional immediately.

What to Do if Your Heat Exchanger Is Cracked

If you suspect your heat exchanger has cracks, don’t attempt a DIY replacement or repair. If you do, you may accidentally expose yourself to harmful and even life-threatening emissions. Instead, allow an experienced heating repair professional to examine the unit and recommend the best course of action. In most cases, the heat exchanger will need to be replaced with a new one.

Contact Tom’s Mechanical in Arlington for Trusted and Outstanding Home Heating Repair Services

A malfunctioning furnace can leave you cold and uncomfortable in your home during the cold winter month. If you’re in need of professional heating repair services in Arlington, TX, look no further.

At Tom’s Mechanical, one of our skilled HVAC professionals will carefully examine and troubleshoot your unit.

Call 972-388-3669 or contact us online to schedule your heater repair service.