New water heater is in.
New tubing is in that goes through the chimney and out to the outside wall and vents on the patio.
When they drilled into the chimney, they pulled out a rat and a mouse, but nothing else and the rest of the shaft is clear as a bell.
New water heater is ye gods efficient and has /excellent/ water pressure.
It also has a contained heating chamber, so it's not going to vent gas onto the floor like the old one did. It could still possibly vent around the hood area, but it shouldn't because the reason that was venting like that, was due to backwash because the water heater was venting through the chimney and so was the furnace, so the two streams of hot stuff were competing with each other and the water heater stuff was getting pushed back out the other way into the basement.
Sabs has gotten a carbon monoxide alarm and we'll put it in tonight.
In the meantime ... I'm going to take a shower with the lovely water pressure after I run the water for a little bit.