How do I Know If There is a Problem with my Heat Exchanger? 

The heat exchanger is an essential component of your heating system as furnaces rely on heat exchangers to provide warm air throughout your home. A broken heat exchanger is much more serious than just a home without heat; broken heat exchangers pose a serious risk to the health and safety of your home.  

In order for a furnace to create heat within the home, it must first combust gas in a sealed chamber. During this time the heat exchanger plays a pivotal role by shielding toxic gas and combustion fumes from entering the blower (a furnace component that distributes warm air through the ducts and vents of your home).  

A broken heat exchanger is a very serious problem and requires immediate inspection by a qualified HVAC technician with a gas license. This blog post will go over how and why heat exchangers can fail and some signs to look out for to determine if your heat exchanger is failing.   

How and Why Heat Exchangers Fail  

Dirty and clogged air filters are one of the reasons why heat exchangers fail. Air filters collect debris and dust particles that exist within your home and need to be changed regularly in order to prevent an area of issues with your furnace unit. Clogged air filters restrict airflow and this puts stress on the components of the furnace which include the heat exchanger and can lead to cracks. To read more about the importance of regular maintenance on your HVAC systems read our blog post “A guide to Furnace Maintenance”

Additionally, it is important that you have an appropriately sized furnace for your home. An oversized furnace can also cause overheating and crack the heat exchanger. 

Ultimately, the most common reason that a heat exchanger will break is from wear and tear. Heat exchangers are made of metal and go through continuous expansion and contraction as furnaces heat and cool down. Over time, the expansion and contraction of heat exchangers will cause metal fatigue and could crack. Most manufacturers recommend the life of a gas furnace to be between 15-20 years.  

In extreme cases, cracked heat exchangers can release harmful toxins such as carbon monoxide, sulfur dioxide and nitrous oxide – which when leaked into your home can cause illness and even death. This is why routine inspection and maintenance is essential for ensuring the good health and safety of your furnace.  

Signs your furnace’s heat exchanger may be cracked 

1. Strange Smells – You may notice a strong and unpleasant odour that smells similar to formaldehyde; if so it could be from a malfunctioning heat exchanger.  

2. Soot Build-up – A white-coloured soot may build up in or around the burners of your furnace.  

3. Corrosion and Cracks – if you find corrosion or cracks in other components of your furnace, you must call us immediately. 

4. Change in the flame appearance – in most furnaces, you can see the flame that heats your air. Remember: blue is normal, but orange and yellow is not.   

5. Audible sounds – if you hear a rattling noise as your thermostat turns on the heat it could be due to a crack in the heat exchanger.  

6. Presence of Carbon Monoxide – A failed heat exchanger may leak Carbon Monoxide into your home. Only a CO detector or alarm will alert you of the presence of CO; however, do not completely rely on a CO alarm.  

What do I do if my heat exchanger is broken? 

There are two main options for moving forward when you have a broken heat exchanger: 

1. Replace the heat exchanger 

2. Replace the entire furnace.  

Depending on many factors including the furnace age, furnace condition and availability; it will affect which option is the best for you. However, the friendly professionals here at Energy Clean have the expertise and industry knowledge about which HVAC equipment is right for your home and family needs and would be happy to help assist you with this decision. 

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Scott Tizzard

President & Founder

Since 2013 I have been helping Canadians by providing the best in class heating and cooling solutions for their homes and businesses. I am hands on with my business and take pride in our work and craftsmanship. We look forward to taking care of your needs. Feel free to contact me directly.