how to stop a furnace vent pipe from leaking condensation
February 28, 2017 · homeowner
<p>I have a gas furnace that is vented thru the roof with a double wall pipe. Several of the joints are leaking, not from outside rain, but from condensation due to the exhaust gases from the furnace.</p>
1 answer
<p>High efficiency furnaces often develop exhaust pipe leaks. Why? Well, it’s actually normal for your high efficiency furnace to build up condensation. Usually, condensation drains via a pipe that leads to a floor drain where it safely exits your home. Sometimes, though, your pipe might develop clogs or there could be a crack somewhere along the tubing, leading to a condensation leak that makes a mess of your home. You’ll have to patch the leaking tubing in order to get rid of the exhaust pipe leak.</p> <p>Standard efficiency furnaces do not have a dedicated condensation pipe, however, and should not be leaking water anywhere under normal operating conditions.</p> <p>So why is your furnace exhaust pipe leaking water?</p> <p>It could be that the <a href="https://www.angieslist.com/articles/why-my-furnace-leaking-water.htm">exhaust pipe is the incorrect size</a>. This could lead to the furnace exhaust cooling down within the pipe, condensing and becoming water vapor, causing a condensation leak.</p> <p>Another explanation for a standard efficiency furnace exhaust pipe leaking water is that the joints in the pipe are vulnerable, allowing condensation to build up. Have a professional check your flue pipe and patch any holes.</p> <p>Long-term exposure to water vapor can cause corrosion in your furnace exhaust pipe, so it’s important to fix any leaks ASAP.</p>