Wish this pic wasn't so fuzzy. It is a diagram of a common 3-valve configuration used to bypass the water heater so as not to unnecessarily fill it up with 6 gallons of antifreeze. One valve blocks the inlet, another the outlet and the 3rd permits the bypass. The handles are typically oblong and turn only 90°. In line with the pipe is open, crossways is closed.
If one forgets to close the bypass after opening the other 2 come spring, the wife will complain about the water not being very hot. Don't ask, I just know. 😊
If this doesn't help, can you post a pic of your valves?