As the chill of winter approaches in Ambler, PA, the last thing you want is to find water pooling around your furnace. If you’ve noticed a leak, you’re probably wondering: “Why is my furnace leaking water?” This isn’t just a minor inconvenience—it’s a signal that something might be wrong with your heating system. Let’s break down the potential causes and what you should do about them.

1. Condensation Leaks in High-Efficiency Furnaces

If you have a high-efficiency furnace (typically with an AFUE rating of 90% or higher), the most likely cause of the leak is condensation. High-efficiency furnaces are designed to extract more heat from the combustion gasses, which cools them down enough to create condensation.

The condensation is supposed to drain out through a PVC pipe, but if that drain gets clogged or the tubing is cracked, you might start seeing water pooling around your furnace. With the wet and chilly winters we get here in Ambler, it’s pretty common for these drains to get blocked up with debris or even freeze, especially if your furnace is in a cold basement or garage.  

What to Do:
Check if the condensation tubing is blocked or cracked. If you’re comfortable with trying to handle it yourself, you can try to clear any clogs yourself using a gentle, flexible tool. But remember, if the tubing is cracked or if you’re unsure how to handle it, it’s best to call in a professional.  If you do see any damage, reach out to us and we can discuss  furnace repair options.  

2. Humidifier Leaks

A lot of homeowners have whole-house humidifiers hooked up to their HVAC units, and they’re awesome for keeping the dry winter air at bay. But if they aren’t maintained properly, they can actually cause leaks. These humidifiers add moisture to the warm air from your furnace, but if the water panel or filter gets clogged, or if there’s a problem with the water line, you could end up with water leaking around the furnace. If that happens, you might need some AC repair to sort things out.

What to Do:
Inspect the humidifier’s water line and panel for signs of clogging, cracks, or damage. Replacing a filter is generally straightforward, but if you find any damaged parts or can’t locate the source, it’s time to contact a professional HVAC technician.

3. Issues with the Internal Drain System

Most furnaces have an inside drain that gets rid of water from the air conditioner or from condensation in the furnace. If this drain gets clogged or breaks, water can start to pool around your furnace. Here in Pennsylvania, where it can get pretty humid, mold and mildew can also block the drain, making things even worse.

What to Do:
Make sure to check your furnace often for any signs of clogs. You can use a flashlight to look inside the drain tube and see if there’s any gunk or buildup. If the water isn’t draining right, it’s a good idea to call us who can take a look and clean the whole system for you.

4. A Problem with the Heat Exchanger

A leaking furnace might also be due to a cracked or damaged heat exchanger, which is a much more serious issue. The heat exchanger is the component that heats the air in your home, and if it cracks, it could potentially leak water. This is rare, but in older furnaces or units that haven’t been well-maintained, it’s a possibility.

What to Do:
This is not a DIY fix. A cracked heat exchanger is a major safety concern and could lead to carbon monoxide leaks. If you suspect this might be the issue, shut off your furnace immediately and call a professional to inspect and repair or replace it.

5. Improper Furnace Installation

If your furnace was recently installed and you’ve noticed a leak, it might have been improperly installed. If the exhaust piping or drainage systems aren’t aligned correctly, condensation can build up and leak out. Unfortunately, even some experienced HVAC contractors can make installation mistakes that can cause leaks.

What to Do:
If your furnace is new and leaking, contact the installer immediately to report the issue. Professional installers should provide a warranty on their work, and they should come back to fix the problem at no extra cost.

6. The Air Conditioner Drain Line

In homes where the air conditioning unit is combined with the furnace, a clogged or damaged air conditioner drain line might be the culprit. Even if you haven’t used your air conditioner for a few months, residual water left in the drain line can cause leaks around your furnace. The temperature fluctuations in Ambler can lead to moisture accumulation in the air conditioner that may leak later.

What to Do:
Inspect the air conditioning unit and its drain line for any visible signs of a clog or break. Cleaning out the drain line is an option, but if you aren’t sure how to do it properly, reaching out to a professional is wise.

7. Frozen Pipes or Coils

When we get those really cold snaps, it’s pretty common for the pipes or coils in your HVAC system to freeze up. Once they start to thaw out, the melting water can leak and pool around your furnace. Here in the greater Philadelphia area, where the temperatures can drop quite a bit, this happens a lot, especially if your furnace is sitting in an unheated spot like a basement or attic. Sometimes, this kind of issue might even call for some repiping to prevent it from happening again.

What to Do:
If you suspect frozen pipes or coils, turn off your furnace immediately and check for any signs of ice buildup. Thawing them slowly is key, and you can use a hairdryer on a low setting for this purpose. If the problem persists, call us to address the issue before it leads to more damage.

8. General Wear and Tear

Finally, if your furnace is older, general wear and tear might be the cause of the leak. Seals can deteriorate, gaskets can wear down, and other components may degrade over time, causing water to leak from your system. In Ambler, where many homes have furnaces that have seen years of use, this is a common scenario.

What to Do:
Regular maintenance is key to extending the life of your furnace. If you’ve noticed leaks and your furnace is more than 10-15 years old, it might be time to consider a replacement. Reach out to an HVAC professional to get an assessment of your system.

Why Is My Furnace Leaking Water When the Heat Is On?

If you notice water leaking from your furnace when the heat is on, it could be due to a few different reasons. One common cause is condensation from a high-efficiency furnace, which can leak if the condensation drain or tubing gets clogged. Another possibility is a leak in your humidifier, especially if it’s overworking to add moisture to your home’s air. Lastly, if there’s a crack in the heat exchanger or issues with the internal drain, you might see water pooling around your furnace. Whatever the cause, it’s a good idea to have a professional check it out to prevent any further damage.

Preventing Furnace Leaks in the Future

Now that you know the potential causes, it’s time to think about prevention:

  • Regular Maintenance: Schedule annual furnace check-ups. This is crucial for preventing leaks and catching issues before they become serious. Many local companies, including us at Plumb Pro Services, offer routine HVAC maintenance plans that make this easy and affordable.
  • Check Your Filters and Humidifiers: Regularly check and replace air filters and inspect your whole-house humidifier, (not your home dehumidifier) to ensure it’s in proper working condition.
  • Keep an Eye on Condensation Drains: Make it a habit to check your furnace’s condensation drain system, especially after major weather events that might cause clogging.
  • Ensure Proper Installation: If you’re installing a new furnace, work with trusted, local professionals like Plumb Pro Services to ensure everything is set up correctly.

Let’s wrap this up!

So, why is my furnace leaking water? There could be a few causes, but we hope this article helps you identify the issue.
A leaking furnace is not something to ignore—it’s a sign that something in your heating system isn’t working as it should. If you’re in the area and dealing with this issue, don’t hesitate to reach out to us at Plumb Pro Services. We hope this answers your question of why your furnace is leaking water.  If you think you need a new furnace installed or your current one repaired, call us today.  Our team of experienced HVAC and plumbing professionals in Ambler can diagnose the problem, provide professional repair, and get your home back to a warm, comfortable state. Give us a call today, and let us take the worry out of your winter heating needs!