Furnace Leaking Water? Condensate Leaks Explained
High-efficiency furnaces produce condensate — a leak usually means a clogged drain, trap or pump.
Seeing water around your furnace is alarming, but on high-efficiency units it's often a condensate drainage issue rather than a catastrophic failure.
Why high-efficiency furnaces leak water
Condensing furnaces extract extra heat and produce acidic condensate that drains away. A clogged condensate trap, blocked drain line, or failed condensate pump causes water to back up and leak.
Other leak sources
A leaking humidifier, blocked AC coil drain (in summer), or improper venting can also cause water near the furnace. Persistent leaks should be diagnosed to prevent corrosion and electrical damage.
Key takeaways
- Turn the furnace off if water is pooling near electrical parts
- Check and clear the condensate trap and drain line
- Test the condensate pump
- Don't ignore recurring leaks — they corrode components
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