Check valves are one way valves. In this case it is used to prevent water from being siphoned down the airline and into the pump when it's not running. This could ruin the pump, empty the tank, shock you, or start a fire.
Check valves are one way valves. In this case it is used to prevent water from being siphoned down the airline and into the pump when it's not running. This could ruin the pump, empty the tank, shock you, or start a fire.