Why Is My Furnace Leaking Water?

The cause of your furnace leaking water can be due to a multitude of reasons. We will list the possible causes and solutions below.


Was Your Furnace Installed With the Correct Flue Pipe Size?

standard-efficiency furnace has a metal exhaust pipe that should not have condensation. If it does, the flue pipe may have been incorrectly sized. The wrong sized flue pipe could allow the the exhaust to cool down and cause condensation in the pipe, then drain back to the furnace and leak out.

Small Leaks can Signify Bigger Leaks to Come

If your house is heated by hydronic baseboard heat, then you may need to close off the valve feeding the heat system so the amount of water available is limited. If this is let go, the water leak will get worse. If this is your issue, give Top Notch a call to assess the issue before it turns into a bigger issue. We likely drain and repair the system, unless the damage is too far along and we need to replace the system.

Did Your Furnace Leak Water While Running the A/C?

Clearing a clogged condensate drainIf you are running a high efficiency forced air furnace then check the drain hose and make
sure you don’t have a clogged condensate drain tube. Condensation from outside air and air conditioning coils contain bacteria and can form slime and clog the condensate pan drain tube.
To clear the slime and prevent the coils can getting clogged again take the following steps: Remove the drain tube and fitting.  Then buy slime prevention packages (Example: AC-Safe Air Conditioner Pan Tablets) and follow the directions. Then install a larger tubing structure. This should permanently eliminate the clogging issue.

condensate pump

You May Have a Faulty Condensate Pump

If your heating system is a multifunction heating, ventilation, and AC, then your leaky HVAC may simply have a broken condensate pump. A new condensate pump is minimal in cost. Before replacing it try pouring water into the pump to see if it turns on, then attempt to turn it on. If it does turn on but the level of water does not decrease, then your tubing is clogged and then it may be clogged and need replaced.