After 2 consecutive 10 minute showers no more hot water? 6 1/2 years old. Had professional visit, drained & turned up the heat. Try for a few days, may have to replace $1,000 install ed. Seems should last at least 10 years. Is this reasonable assessment & next step? Model MI40T6FBN serial DC8860395. It is 6 months past warranty end. We are new home owners of 1 month.