Hi There,
I'm trying to figure out what's going on with my water softener. I do not know the age of the system. The problem started with a drop in water pressure to the house, bypassing the softener fixed the problem. In addition to this, when I do run the softener the brine tank backs up. At the beginning of the slow rinse/brine cycle, brine is initially drawn into the air check valve and then slowly you can see the direction of the water reverse.

I have taken apart the control unit and the following has been checked:

-Injector/screen are clean
-everything has been rinsed for a blockage
-brine line should be clear as it initially draws brine and backs up water just fine.
-drain line gets good flow.
-flapper valves look ok. One of the larger ones was a little bit rougher, but not too bad.
-The air check valve fills with water fine. there is a bubble in there throughout the cycle.

Any thoughts, ideas? Could the resin be the issue?