I have no hot water. I checked the fuse box and everything is fine there. I looked at my Rheem Water Heater, Model No: PDV40, Type: Gas- Natural. It has a digital theremostat, the green light where it say's "Vacation Warm" is on and the yellow light "hot" is on at the same time. How do I reset my water heater or get the "Vacation" light to go off???