Water heater vent pipe not extended to top of (roof) vent jack
An inspector wrote this:
The vent pipe did not appear to extend all the way up to the top of the vent jack. This can cause improper venting or back venting at the draft hood. It presents a carbon monoxide and fire risk. We recommend correction by a licensed venting contractor.
I've shown pictures to a few plumbers but haven't been able to get anyone to get in the attic to take a look yet. I want to understand how this *should* be fixed so that I'm prepared to ask questions when a plumber checks it out.
I took the first picture by looking up the vent pipe. The wood is the ceiling of the attic, which appears to have been cut away when installing the pipe. Based on the inspector's writeup it sounds like this pipe is supposed to fully connect to the vent jack so that it's sealed (so that the pipe doesn't let any exhaust escape anywhere except out of the jack). Is that right?
From showing plumbers pictures I got a few pretty different quotes. One plumber said they might have trouble getting pipe like this, and if they can't I should just install a tankless water heater. How would you go about fixing this?
Thanks!