A furnace exhaust pipe, or flue pipe, without leakage

A furnace exhaust pipe, otherwise known as the furnace flue pipe, is used to help vent harmful gases such as carbon monoxide outside of your home. The furnace exhaust pipe, typically made of galvanized metal, tends to run from the furnace’s combustion chamber and up to the attic where it is vented outdoors.

Have you noticed that your furnace exhaust pipe is leaking?

Then you’ve come to the right place. One common yet serious concern is a flue pipe that is leaking water or condensation, or even gas. Both of these flue pipe leaks are cause for concern, since they can indicate an even bigger problem – a carbon monoxide leak.

In this blog post, we’ll discuss

  • What to do if your furnace exhaust pipe is leaking water
  • What to do if your furnace exhaust pipe is leaking gas
  • The possible causes of these different leaks
  • How to fix or avoid them in the future

If you don’t find the answer you came looking for, leave a comment on this post and we’ll answer as best we can.

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Why is My Furnace Exhaust Pipe Leaking Water?

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.

Standard efficiency furnaces do not have a dedicated condensation pipe, however, and should not be leaking water anywhere under normal operating conditions.

So why is your furnace exhaust pipe leaking water?

It could be that the exhaust pipe is the incorrect size. This could lead to the furnace exhaust cooling down within the pipe, condensing and becoming water vapor, causing a condensation leak.

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.

Long-term exposure to water vapor can cause corrosion in your furnace exhaust pipe, so it’s important to fix any leaks ASAP.

Why is My Furnace Exhaust Pipe Leaking Gas?

If your furnace exhaust pipe is leaking condensation, it could also be a sign that your pipe is leaking gas – which is not a small issue. If you notice any bubbles where water is leaking from your flue pipe, it’s important to have a professional inspect the pipe and your home for carbon monoxide leaks.

Remember – keep a carbon monoxide detector near your furnace at all times in order to prevent deathly CO2 poisoning.

We’ve gone over several causes of exhaust pipe leaks in your furnace, what to do about them, and how to prevent them in the future. Exhaust pipe leaks are a serious cause for concern, since they can indicate a much greater issue. If you suspect that your furnace has an exhaust pipe leak, call your local furnace repair specialist. And if you ever need help with your furnace repairs in Modesto, Tracy, or anywhere in between, the Irish Heating and Air family is always happy to help.