How does a 3-valve bypass work?

Many homes are designed with 3-valve bypasses, generally found on the plumbing directly before an appliance. This type of valve allows you to choose if water flows into the appliance, or bypasses it completely. 

Normal Service Flow

To allow water into the softener, confirm the inlet and outlet valves are OPEN. CLOSE the center bypass valve. This will allow all incoming water to pass through the softener before supplying your faucets and fixtures:

Bypass Water Flow

To bypass the softener, CLOSE the inlet and outlet valves. OPEN the center bypass valve: