Upon arrival I turned off the water to the unit, I also turned off the electric at the breaker. Than I removed the old water heater and replaced it with a 30 gallon Rheem low boy water heater. I also installed an off and on switch for the water heater. When I had completed my work I turned the water back on and also the electrical. Within 15 minutes the water had began to heat up I had the customer to check the heat to make sure it was to his liking.