Finding water leaking from the furnace is a common problem, especially during the colder months. While it’s easy to assume the furnace itself is the culprit, the water might be coming from somewhere else entirely.
No matter the source, it’s important to address furnace leaks quickly. Water can damage your home and even create safety hazards.
This article will walk you through the process of identifying the source of the water, troubleshooting common causes, and determining the best course of action to resolve the leak.
Is it really your furnace?
Before you panic, you’ll need to rule out other possible sources. It’s easy to think the water is coming from your furnace when it’s actually originating somewhere else.
Start by checking your water heater, water softener, iron filter, and dehumidifier for leaks. If it’s summer, the water may be condensation from your air conditioning system.
Sometimes high humidity and condensation can create what looks like a furnace leak. It’s worth checking these things before you call a professional.
Common Causes of Furnace Leaks: A Comprehensive Overview
If you see water around your furnace, don’t panic, but don’t ignore it, either. Here are some of the most common reasons for furnace leaks.
Condensate-Related Issues
High-efficiency furnaces create condensation as part of their normal operation. That condensation has to go somewhere, so these furnaces have a drain line that carries the water away. If that drain line gets blocked by algae or debris, you might see a puddle near your furnace. You can try disconnecting the hose and flushing it out to clear the blockage.
Furnaces also have a condensate trap, which prevents sewer gases from backing up into your home. These traps can get clogged, too, and you’ll probably need a professional to fix it.
Some furnaces also have a condensation pump to move the water. These pumps typically last about 3 to 6 years. If they fail, they can leak.
While you’re looking at the condensate line and pump, inspect the drain hose itself for cracks or wear. Replacing a worn hose is usually a quick and easy fix.
Venting and Exhaust Problems
Your furnace has vents and intake pipes that must be properly sealed to keep water out. Cracks or splits in these pipes can allow water to enter. Heavy rain or snow can also be drawn into the vent. Make sure you clear any snow away from the intake pipe to keep it clear.
In colder climates, condensation can form inside the intake pipe.
Internal Furnace Issues
High-efficiency furnaces have a secondary heat exchanger. If this component corrodes, it can leak. You’ll need a professional to repair this.
The inducer motor helps exhaust gases. If you see leaks near it, that could mean there’s a problem with the motor itself or its seals.
Humidifier and air conditioner leaks
Sometimes the water you’re seeing isn’t coming from the furnace at all. It may be related to your humidifier or air conditioner.
Humidifier leaks
If you have a humidifier attached to your HVAC system, it may be the culprit. Common problems include a pad that needs replacing, a drain tube that’s clogged, or a filter that wasn’t installed correctly.
To troubleshoot, try replacing the humidifier pad, flushing out the drain tube, and double-checking that the filter is installed correctly.
Air conditioner leaks
Problems with your air conditioner’s drain pan or frozen evaporator coils can cause leaks even when the furnace isn’t running.
Check the AC drain lines, the evaporator coil pan, and the coil itself for any blockages or leaks.
Because of their proximity, AC leaks often disguise themselves as furnace leaks, so it’s important to rule out the AC as a source of the water.
Dangers of a Leaking Furnace
A water leak and a furnace don’t mix. If water comes into contact with the electrical components of your furnace, you could be at risk for electrocution or fire. Ignoring a leak can also lead to expensive repairs down the road.
Water leaks can also cause mold to grow. Mold can damage your home and make you sick.
If you see water leaking from your furnace, follow these steps immediately:
- Turn off your thermostat.
- Turn off the furnace switch.
- Use cleaning cloths to soak up any standing water.
- Dry off the furnace unit.
- Call a qualified HVAC technician.
DIY vs. Professional Repair: When to Call for Help
Sometimes, you can fix a furnace water leak yourself. For example, if you see a clogged drain line, you can try clearing it. If a vent is blocked with snow, you can remove the snow.
However, you should call a professional for anything complicated, like a leaking heat exchanger. Refrigerant issues and electrical repairs always require a qualified technician.
Regular professional inspections and maintenance can prevent leaks in the first place. Remember, even well-intentioned DIY repairs can cause more damage. If you’re unsure, it’s always best to call a professional.
In Summary
Like any complex appliance, your furnace works best with regular maintenance. Keeping your furnace well maintained can also help prevent leaks.
If you do see water leaking from your furnace, try to follow the troubleshooting steps discussed earlier to identify the source of the leak. If you can’t find the problem yourself or the leak is due to a cracked heat exchanger, call a professional HVAC technician.
For optimal furnace performance and safety, it’s often best to work with a qualified professional. By taking swift action, you can protect your home and family from the risks associated with furnace leaks.