Someone needs to tar those roofers then throw them off the roof... Thats how you kill people. The open return is just icing on the cake. Its a wonder they didn't die. Someone that I know from the parts houses is a nincompoop that shouldn't be doing his own jobs, he almost killed a married couple with a disconnected fireplace flue. They were both in the hospital for almost 2 weeks and likely have permanent damage. That wasn't nearly as dangerous as what I see in those pictures...
America; first we fight for our freedom,
then we make laws to take it away.
It really breaks my heart to hear these stories, and the ones about bypassed disconnects, and really every safety concern. It's too bad there are so called "technicians" out there like them who make the real techs like us look bad!
Back in the early 80s I remember seeing all kinds of gas water heater installs where there was no flue pipe. These jobs were all over in virginia and the reasoning behind them was that the water heaters were installed in the basement and the basement construction was so loose that enough outside air would infiltrate the space.
Anyhow.... In this case....Id say it was the roofers. probably got some guys to reroof the house.... and they were either too damn sorry or just forgot to cut the hole and fix the vent.
Id put my money on just too sorry to fix it right.
Coming up with a new signature..... Aint nobody got time for that.