Why is My Furnace Leaking?
TechXpert verified by Ken Kontra
A condensate leak is the most common cause of a water leak from a furnace. You’ll want to act quickly when you notice your furnace leaking, so you can restore heat to your home and prevent water damage in the surrounding area.
The Culprit Behind a Leaky Furnace
While a condensate leak is the most common explanation for why your furnace is leaking, there are things that could be giving your unit a hard time.
As your furnace heats up, it produces condensation, which is carried through the pipes in the system. If any of these pipes are clogged or broken, the condensation will instead be forced to leak out and collect around the base of your furnace –– and that can lead to water damage.
If you notice water around your furnace, it may not be coming from your furnace. In some cases, the water can be traced to a clog or break in your humidifier. Your humidifier connects to your plumbing system to produce moisture in the air, and if it breaks, that water can collect around your furnace.
Your plumbing may be framing your furnace. Clogged or broken plumbing pipes can wreak havoc in your system’s drainage system, so they should be repaired or replaced quickly to lift the burden off of your furnace. If plumbing problems go undetected, all sorts of leaks, puddles, and floods can result.
Filthy air filters are a lost cause. If the air filters in your furnace are dirty or clogged, they won’t be able to feed air through the evaporator coil, and that coil will freeze and eventually start to drip water around your furnace.
If you live in milder climates where you use both your furnace and AC during the same season, your AC may be what’s leaking rather than your heater. If this is the case, it’s important to fix your AC leak –– and to be safe, check for any potential problems that could cause your heater to leak, too.
Another potential (and expensive) reason for a heater leak is an issue with the heat exchanger. If your heat exchanger is malfunctioning, you may need to replace the entire furnace.
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