That liquid can then leak into your home. However, the the flue vent is undersized, the flue gases have trouble escaping, causing them to lose energy and condense into a liquid. The flue vent’s job is to vent out all flue (combustion) gases from the furnace. Mid-efficiency furnaces can create condensation if their flue vent is undersized. If the pump breaks, then the condensation will simply build up and spill over into your home. It does what it says on the tin: pumps condensation from the furnace to outside of your home. But if your furnace is located in a basement, that may not be possible.Įnter the condensate pump. Normally, to let condensation exit out the condensation line, your furnace would let gravity do all the work. It could be that the… Cause #2: Condensate pump is broken The condensate line isn’t the only cause of this issue. That liquid is what may be pooling around your furnace. A secondary heat exchanger can extract even more heat from the combustion gases before sending it out the exhaust pipe.īecause the secondary heat exchanger steals so much heat, the combustion gases lose enough energy to condense into a liquid. Well, a primary heat exchanger extracts heat from combustion gases and then imparts that heat to your home’s air. High-efficiency furnaces create water because they have something that normal furnaces don’t: A secondary heat exchanger. Why do high-efficiency furnaces create water, anyway? The solution: Kenny flushed the condensate trap and lines to clear them so the condensate can properly drain. After our technician, Kenny, ran a full system diagnostic, he found the condensate trap (part of the condensate line) was not draining properly. One of our Westfield customers, Annie M., had the “clogged” issue. Or if the line breaks the water will leak around the furnace. However, if that line becomes clogged, the water backs up into your home and pools around the furnace. That water needs to be drained out of the home via a PVC pipe called the condensate line. High-efficiency furnaces (90+ percent AFUE) create water when they run (we’ll explain why in a bit). Cause #1: Clog or leak in the condensate line A common call we get from Westfield homeowners is “Why is water leaking from my furnace?”The cause? A furnace could leak water for 4 different reasons:įor all these issues, you’ll need to call a furnace repair technician.īut if you’re curious about what these issues are in more detail, read on.Īs a bonus, you’ll also see how much it would cost to fix a clogged condensate line-the most common cause of this issue.

Humidifier on furnace leaking