Okay, I have a Rheem Criterion Model Number RGDG-07NAUER. My problem started when I had a contractor come and install a vent in my bathroom. He ran a air duct into my heating duct which he bent my inducer blower. Some how that cause my control board to be burnt out. I replace it and the flame sensor and now when I turn on my heater all that happens is that it will start up and shut down after 2 seconds. This will happen twice then the fan will kick start and no heat will come out of the heater.

Please help...

Are you saying that a Contractor installed your bathroom fan vent through a heating duct?? How was he anywhere near the inducer motor, it is on the furnace and behind a panel? Maybe a bit more explanation... Thank you.