I want to remove these two metal things, but I'm not sure what they are or if they serve an important purpose.
These things are located in a 10x8 or so water heater closet at the end of our 40-year-old house. The closet is accessed through its own exterior door, not through the house, and it is not temperature-controlled, but it does share a drywall wall with our bedroom. Which is barely insulated, but that's a different thread.
The current water heater is a gas model that was installed a couple years ago.
Neither of these things is connected to the current water heater at all, at least not below ceiling-level, where I can actually see what's going on.
1) Thing A just seems to be a short metal vent-like cylinder that surrounds a hole in the ceiling. When I reach inside it, there is nothing above it on the other side of the ceiling in the attic.
Is this left over from an old water heater? Can I remove this and patch the ceiling, or is there to ensure plenty of fresh air and no buildup of (fumes? gases?)?
2) Thing B is a long metal tube that presumably goes through the ceiling. It's attached to the wall and open on the bottom. Nothing else is attached to it. (The copper tubing to its right runs right past it, but isn't actually attached.)
Same question - is this left over from a previous water heater? Can I remove this and patch the wall and ceiling, or is it serving a useful purpose?