Do not leave a wet exhaust line with a built-in water dam at a reducer.
Check
Look for standing water, rust, dripping, or low-pocket seams.
Confirm the air/moisture direction and intended drain point.
Check whether a flat-bottom eccentric fitting is required.
Verify material and exhaust type before swapping fittings.
Document any corrosion or liquid leakage.
Steps
Look for standing water, rust, dripping, or low-pocket seams.
Confirm the air/moisture direction and intended drain point.
Check whether a flat-bottom eccentric fitting is required.
Verify material and exhaust type before swapping fittings.
Document any corrosion or liquid leakage.
Say this to your foreman
The reducer at [location] is creating a bottom pocket that holds condensate. I checked slope and drain direction. Do you want an eccentric/flat-bottom fitting or revised drain detail?