Thread: Exhaust Pipe leak

I noticed recently (not sure how long it's been happening) that there is a slow steady leak coming from the exhaust pipe of my Carrier furnace. I would guess it is about 6 drips per minute.

The drip is happening at the joint where the vertical pipe that leaves the furnace goes horizontal for the first time. The rest of the exhaust pipe is exposed in my basement and I can see that there are no other leaks along this line. Also, the pipe on the outside of my house appears to be free from blockage and there is no noticeable moisture build up.

You can see in the second image that as the drip goes down the drain there is some sediment build up on the PVC edge. It looks a lot like the sediment that comes out of the drainage hose and goes into the drain in the floor. It doesn't look like there is any caulk on the PVC joints.

Is this something I should have a repairman out to look at/fix? I had my furnace inspected this fall, is this something they should have caught?

Thanks

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The 90 is leaking and should be replaced. It looks like the installer didn't use primer before he glued it.

It doesn't like like the joint was primed or maybe even properly glued. Consider having it pulled apart and redone. Additionally that is a short radius 90 in the 1st photo, to the best of my knowledge those are not allowed on the exhaust pipe. You may also want to consider having the hvac guy check out the overall run. Depending on various conditions it is common to get some moisture coming back towards the unit. From what you say and the pics it seems a bit much. Could be a pitch, exterior termination, weather orientation, run length or other issue.

Good call on the 90, the pitch is supposed to be back to the unit.

Thanks for your input guys. Looks like I'll be replacing some PVC soon...

You guys are right. On a condensing furnace, you must use primer on all joints. Additionally all the 90's need to be medium to long radius. The vent pipe is supposed to pitch back to the furnace and from there to a plumbing drain. One other thing to note. The water from a condensing furnace is mildly corrosive and shouldn't be allowed to drain into a copper drain. It can eat through the copper over time.