Can't Figure Out Water Heater Bypass (With Pic)

[thompson521dc]

I have looked and I know this is a played out topic but my water heater bypass seems to be missing a knob. Can anybody look at this pic and tell me if what I have should work, and if so how. Thanks!!

 

[C Nash]

In the position the levers are now,the water by passes the heater. Turn both the other way and water goes into the heater. hope this helps.