Why Is My Furnace Leaking Water?

When you notice a puddle below your furnace, there’s a good chance condensation is to blame. Condensation leaks are nothing to stress about, but it’s still a good idea to call a professional just in case. Ignoring the problem can lead to water damage. And if condensation isn’t the culprit, a leak might be a sign of a bigger problem.

Common Causes of a Leaky Furnace

Condensation

High-efficiency gas furnaces feature two heat exchangers to extract as much heat as possible from the combustible gases. As the gases cool, condensation causes water (condensate) to form. This is why high-efficiency furnaces are often referred to as condensing furnaces. Normally, the condensate drips into a drain pipe on the floor and washes away.

When you notice water pooling beneath your furnace, the condensate line may be clogged or cracked. This line is supposed to funnel water from the secondary heat exchanger toward a floor drain. Thankfully, condensate lines are often PVC, making them easy to repair or replace if necessary.

Condensate pumps move the water through condensate lines toward the drain at the base of your furnace. If the pump malfunctions, the condensate won’t follow the appropriate path and can cause your furnace to leak water. A broken pump might sound like a costly repair, but they’re less expensive than you might think.

A clogged floor drain might also cause water to pool beneath your furnace. This may look like your furnace is leaking water. But in reality, it’s just an issue with the plumbing. You might even be able to clear the blockage with a simple drain snake.

Air Conditioning

During months with milder weather, it’s common to switch back and forth between using your air conditioner and furnace. It might look like your furnace is leaking if the heating and cooling components of your HVAC system drain in the same place. But air conditioners also produce condensation through a process similar to that of a high efficiency furnace.

This water collects in the condensation pan which can leak onto the heating system. So if you’re wondering why your furnace is leaking water, it might not be your furnace at all. This is one of the many reasons why it’s important to have a professional inspect your system at the first sign of a leak.

Whole Home Humidifiers

Rather than using portable humidifiers in every room, whole home humidifiers connect to the heating system. They add moisture to the air throughout the entire home, easing the problems of dry air in the winter months. Although they’re supposed to only add moisture to the air, sometimes they leak into the furnace instead.

When your whole home humidifier leaks into your furnace, it doesn’t have a simple path to escape. As a result, the water often leaks out of the furnace and onto the floor. An experienced HVAC professional will be able to track down the source of the leak to prevent the issue from recurring.

Heat Exchanger

As mentioned above, the heat exchanger saps heat from combustible gasses in a furnace and uses it to heat your home. Over time, it’s possible for a heat exchanger to crack, which can cause Carbon Monoxide leaks. The crack can be a much more serious issue than the leak itself. If the heat exchanger has an issue it may even trigger a shut off valve on the furnace to prevent more dangerous problems.

Unfortunately, furnace repair is rarely the best option with a malfunctioning heat exchanger. Replacing the heat exchanger is normally very expensive, unless the furnace is under the manufacturer’s warranty. In most cases the best option is simply to replace the furnace altogether. The good news is that if your furnace is leaking water, it’s probably not the heat exchanger. But you should still contact an HVAC technician to have a look to be on the safe side.

Regular heater maintenance is the best way to prevent your furnace from leaking. But if you need furnace repair in St. Charles or the surrounding areas, call Blue Frost Heating & Cooling. Whether the issue is a leaky furnace or something else altogether, we’ll get to the root of the problem and fix it once and for all.