To avoid confusion over debits and credits, avoid thinking of them in the way that they are used in everyday language, which often refers to a credit as increasing an account and a debit as decreasing an account. For example, if our bank credits our checking account, money is added to it and the balance increases.
One way to reduce the frequency of this occurrence is to maintain an air pocket at the top of the water heater tank. This air pocket will form in the tank by design - however, it will be reduced over time by the everyday use of your water heater. To replenish this air pocket: Turn off the water heater.
Heat migration can be eliminated by installing Heat Trap dielectric nipples on the water heater. One common cause of warm water on a cold water line results from the installation of a hot water instant on recircutor that uses the cold water line as the return path rather than having a dedicated return line.