My pellet is having trouble shutting off. It will take close to three hours. I have changed the circuit board and ESP probe twice. It is vented with the direct vent set up. I was told it should shut off around 45 minutes from being turned off. The stove was purchased a few years ago from a vendor 50 miles away. No vendors will send a repair technician out since I did not purchase the stove from their store. Looking for help please.