My DFSB483D is about 2.5 years old. Suddenly, there is something wrong with the defrost. It will defrost but stay at +10F for over 4 hours. Service has replaced the thermostat, the electronics, the temperature sensors, fixed a loose wire at the fan towards the fridge; all with no success. Viking is of no help at all. Maybe this is just the worst refrigerator in the world? For a $7,500+ product from a premium brand I sure expect more in terms of reliability, service and care for customers!