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12 Reasons Why Your Furnace is Leaking

12 Reasons Why Your Furnace is Leaking

If you’re Googling “why is my furnace leaking?”, Modern HVAC can help! At our heating and cooling company, we understand that a leaking furnace can be a troubling sight for any homeowner. Not only that, but the cause of the furnace leak and the solution can vary widely.

At Modern HVAC, we understand the urgency and complexity of your situation. Our furnace technicians are here to provide you assistance with your leaking furnace. If you want to understand more about troubleshooting your furnace leaks, please refer to our article on what to do when your furnace is leaking.


Common Questions on Why Your Furnace is Leaking

Why is my furnace leaking water when the AC is on?

When your AC is running, it generates condensation, which is usually drained away through a condensate line. If this line is clogged or damaged, the water can back up and leak around your furnace.

Additionally, if the drain pan is cracked or overflowing, it can cause leaks. Regular maintenance and cleaning of the condensate drain line can help prevent this issue.

Why is my furnace leaking water when the heat is on?

If your furnace leaks water when the heat is on, it’s likely a high-efficiency model that produces condensation during operation. This water is typically drained away, but a clogged drain line, faulty condensate pump, or damaged drain pan can cause leaks.

In rare cases, a cracked heat exchanger might be the culprit, which requires immediate professional attention due to safety concerns.

Why is my furnace leaking water from the bottom?

Water leaking from the bottom of your furnace usually indicates an issue with the condensate drain system. Common causes include a clogged or broken drain line, a malfunctioning condensate pump, or a cracked drain pan.

If the leak persists after checking these components, it’s best to consult a professional to ensure there isn’t a more serious problem with your furnace.


12 Reasons Why Your Furnace is Leaking

Below is a detailed guide on 12 common reasons behind furnace leaks and how our expertise can assist you in resolving these issues efficiently.


1. Condensation Water

One of the most common reasons why your furnace is leaking is the formation of water.

In fact, condensation is a frequent culprit behind furnace leaks. This phenomenon often occurs during colder months, leading to water accumulating on your floor.

Should you notice your furnace cycling more frequently or observe increased water presence, it might signal a leakage issue that requires prompt attention.


2. Clogged Filter

Another possible reason why your furnace is leaking is a clogged filter.

If your furnace filter becomes clogged with dirt and debris, it will cause your system to work harder than it needs to. This will lead to condensation buildup and leaks.

Changing or cleaning your furnace filter regularly not only prevents leaks but also improves your indoor air quality and furnace efficiency. Questions? Contact Modern HVAC to help troubleshoot your clogged filter or other issue related to a leaking furnace.

Related: How Often Should You Change Your HVAC Filter?


3. Clogged Air Return

Your furnace’s air return plays an important role in circulating air throughout your home. If this pathway becomes obstructed, it can lead to overheating and subsequent leaks.

To help combat the chances of a clogged air return, you should schedule routine tune-ups and cleaning of air ducts. Not only does this help to reduce the risk of furnace leaks, it also helps to maintain better air quality.


4. Vent Pipe Obstruction

If your furnace is leaking, it could also be a vent pipe obstruction.

Your furnace’s vent pipe is essential for expelling exhaust gases safely outside. A blockage in the vent pipe not only poses a risk of leaks – it can also lead to dangerous gas buildups inside your home.

It’s vital to have a skilled HVAC technician inspect these pipes periodically for any signs of obstruction or damage. A clear vent pipe helps to promote a safe and leak-free furnace.


5. Pipe Issues

Over time, pipes carrying water or exhaust can develop cracks or condensation issues, leading to leaks. Seasonal checks, especially before the heating season, can identify potential problems.

Having a local furnace technician insulate the pipes or repair any damages right away can prevent leaks and protect your home from water damage.

Related: 8 Signs Your Furnace Needs a Replacement

Drain Line Issues

6. PVC Drain Line Issues

Another possible reason why your furnace is leaking is a PVC drain line problem.

The PVC drain line plays a pivotal role in managing condensation and waste water from your furnace. A blockage here can lead to backup and leaks.

Routine furnace maintenance from a local trust HVAC company includes checking these lines for clogs and ensuring a clear path for water to exit, preventing leaks and potential water damage.


7. Blocked Drain Line

Another factor that could be contributing to your leaking furnace is a blocked drain line. The drain line connecting your furnace to the septic system must remain clear to prevent water backup and leaks.

You can take steps to temporarily fix the blocked drain line – such as wrapping a rag around the line’s end to clear debris. For a long-term solution, you should schedule a regular professional check to ensure long-term furnace functionality and leak prevention.


8. Dirty Furnace Filter

Another possible reason why your furnace is leaking is a dirty furnace filter. Similar to a clogged filter, a dirty one will impede airflow and may contribute to water accumulation around the furnace.

Ensuring the filter is clean or replaced when necessary is a straightforward but effective step in leak prevention and maintaining optimal furnace operation.


9. Drain Pan Issues

The furnace drain pan collects condensation, which should be expelled through the drain line. If the pan is damaged or the line is clogged, water can overflow and cause leaks.

Regular inspections and cleaning of the drain pan and line prevent such issues, ensuring proper water drainage. Contact Modern HVAC to have us look at your drain pan and resolve any other possible issues related to your leaking furnace.


10. Condensate Pump Failure

The condensate pump is essential for removing water generated by the furnace. If this part of your furnace fails, water can accumulate and lead to leaks.

Early detection of pump issues, through noise or water level checks, allows for timely repairs or replacement, avoiding leaks and further damage.


11. Humidifier Blockages

Another factor that could be contributing to your furnace leaking is a humidifier blockage. Furnace humidifier adds moisture to the air, but if it becomes clogged, it can cause excess condensation and leaks.

Regular cleaning and maintenance of the humidifier, including replacing filters and clearing blockages, ensure it operates correctly without contributing to leakage problems.


12. Secondary Heat Exchanger Malfunction

Lastly, let’s discuss the secondary heat exchanger. This part of your furnace helps regulate your home’s temperature efficiently. However, issues like clogs with calcium carbonate can lead to your furnace forming condensation or leaks.

Professional furnace leaking inspections from the Modern HVAC team can identify and resolve problems with this component, ensuring your furnace functions efficiently without leaks.

Read More: Heating and Cooling Guide


Is Your Furnace Leaking? Contact Modern HVAC!

If your furnace is leaking, our technicians can help! At Modern HVAC, our Carrier certified dealers emphasize the importance of proactive maintenance and timely repairs to prevent furnace leaks and ensure your heating system’s longevity.

Our furnace technicians are equipped to handle all aspects of furnace maintenance, from clearing blockages to repairing critical furnace parts. We also perform installations, replacements, and repairs.

Trust our furnace technicians to keep your heating and furnace systems running smoothly, safely, and efficiently. If you’re experiencing furnace leaks or want to prevent future issues, please contact Modern HVAC for furnace troubleshooting support!


Service Area

Modern Sheet Metal serve the Fox Cities, including Appleton, Neenah, Menasha, Kimberly, Kaukauna, Darboy, and Greenville. We have been serving your local area for more than 60+ years!

Further Reading:

Modern Sheet Metal provides furnace and air conditioner service, repair, replacement and installation throughout Appleton, Neenah, Menasha, Darboy, Kimberly, Kaukauna and Greenville. Please call us at 920-733-4713 to discuss your residential or commercial heating & cooling needs!