Hi,
I have a Wilkins Zurn 975XL backflow preventor installed on the
irrigation system. Had removed it for Winter and installed it this
month after the last freeze.

After installing the preventor, water has been flowing through the vent
below. I checked all the 4 valves and turned them to off position using
a flat head screw driver. The preventor is installed in the correct
direction, verified that with the arrows and compared it with my
neihbor

I verified that that sprinklers run when turned on, that eliminated any
blockage in the irrigation system. In fact water continues to flow
through the vent, when the preventor is disconnected from the
irrigation system.

Any ideas? Do I need to do something else to make the preventor work?

TIA

:-)abhi