I have a Rheem power vent water heater that seems to have an issue... I have no hot water. The blue light at the bottom blinks 8 times pauses blinks once and the pauses... I have everything shut off right now but would like to know what the flashing light means.

Your answer is on page 37: You have a problem with the FV-Flammable Vapor sensor. It could be dirty or you are storing gasoline or flammable paint thinner, etc. near the water heater. See: https://dl.dropboxusercontent.com/u/...al_AP15761.pdf
You may have to clean it or replace this sensor. Dust can cause the problem.