Q. What is the water heater by pass and how does it work?
A. The by pass is the white hose in the picture above. It is used to avoid filling up the hot water tank with antifreeze when winterizing. Note the tank needs to be drained during the winter and should be filled before heating the water in the spring.
At this point all the anti-freeze should be out of the lines. Go into the PUP, open the access way to the water heater and look for the bypass valve. Turn it so that the dilute bleach water can now enter the the heater.
Go into the PUP, open the access way to the water heater and look for the bypass valve. Turn it to bypass the heater. You can purchase or make a bypass kit if needed. Note the bypass line eliminates filling up an empty heater with Anti-freeze.