3 Ways Gas Furnace Maintenance Extends Your Heat Exchanger’s Life

Even if you're not an HVAC expert, you've probably heard of your furnace's heat exchanger. The heat exchanger is a critical component of any furnace that uses combustion to generate heat. This radiator-like device allows the furnace to extract heat energy from the exhaust gases while safely funneling combustion byproducts outside your home.

Although heat exchangers are relatively simple, they're critical to maintaining your furnace's safety. A cracked heat exchanger can allow deadly gases into your home, and replacing a heat exchanger is so costly that replacing the whole furnace is often more cost-effective. Fortunately, scheduling routine annual maintenance can help extend your heat exchanger's life in these three crucial ways.

1. Minimize Overheating Risks

Your heat exchanger must contain extremely hot combustion gases, but that doesn't mean this metal component can withstand infinite heat. High temperatures can cause the heat exchanger to undergo drastic expansion and contraction cycles, resulting in metal fatigue. Given enough time, these cycles will cause small cracks that can allow gases to escape.

Poor airflow (often due to dirty air filters) can cause the heat exchanger to overheat, greatly increasing the odds of crack formation. Routine annual maintenance will allow a technician to ensure that you're changing your filter often enough to prevent overheating. Your technician can also advise you if you need to change your filter more frequently or use a different type of filter.

2. Ensure Safeties Are Operating Correctly

All furnaces contain several safety switches that help ensure your furnace doesn't operate unsafely. These switches monitor conditions that can pose a safety hazard or result in further damage to your furnace. The high-limit switch is one such safety device. This switch monitors the temperature near your heat exchanger, shutting the furnace down if it gets too hot.

Annual maintenance visits will typically include an inspection of your furnace's safety switches to ensure they're functioning correctly. A faulty high-limit switch may allow your furnace to run even when temperatures are too high, causing unnecessary wear on the heat exchanger. Inspecting (and replacing, if needed) these switches will help prevent these easily avoidable problems.

3. Detect and Correct Incomplete Combustion

Gas furnaces operate most efficiently with the correct ratio of fuel and oxygen. An incorrect combustion ratio (too much air or fuel) will result in incomplete and dirty combustion, potentially creating a flame that burns inconsistently or too hot. Since high temperatures in the combustion chamber are your heat exchanger's number one enemy, this condition can ultimately shorten its life.

Annual inspection visits often include a combustion analysis. This analysis can detect efficiency problems with your furnace and allow your technician to investigate and correct issues that may lead to incomplete combustion. Not only will correcting these issues protect your heat exchanger, but it will also help your furnace to run more cheaply and efficiently. 

For more info, contact a local company like Allied Mechanical & Electrical, Inc.