Installing a circulation pump for a water heater is a method for obtaining a constant hot water situation at most faucet locations that the pumps return pipe is connected.
Shut off all electrical power and main water pressure to the hot water heater. This may entail the closing of the main water valve to the home depending on the plumbing situation in your own residence. Cut into the hot water line that is coming from the water heater. You will also need to cut into the cold water supply line that feeds the hot water heater. The check valve will be placed on this pipe so only cold water can flow into the water heater and the re-circulated hot water cannot flow out and back into the cold water line. Most circulation pumps must run 24 hours a day and require a dedicated duplex receptacle to provide power.