The filter needs changed after each wash cycle.  Check the filter every time you come to the barn or leave the barn.    To change it do the following:

1. If milk was picked up recently, the wash lines may need unhooked.  Follow this procedure first before changing the filter.
2. Wash hands – hands must be clean when handling the milk filter
3. The filter with a blinking green light needs changed.  Only change the filter when the red light is off.  Turn the blinking green knob to the right, 1/4 turn.
4. Pull the filter holder out part way.
5. Remove the spring from the handle.  If it is difficult to remove, twisting the spring away the tank can help.
6. Pull the inner holder completely out, leaving the spring and filter inside the filter body.
7. Set the holder in the vat.
8. Remove the old filter from the spring (spring can stay in the filter body).  Discard the old filter.
9. Using the hose, wash the floor in front of the tank where milk splashes out of the tank valves.
10. Rinse the tank valve inlet through the screen.
11. Rinse the holder with water, especially near the handle, where there is milk residue.
12. Return the hose to the rack and turn the water off!
13. Pull the new filter up over the barrel of the filter holder, and then fold the other end of the filter over the end of the holder.
14. Insert the filter into the spring, and pull the spring up on the barrel.  It helps to twist the spring away from the tank again.
15. Insert the filter and holder into the filter body, and screw the ring back on.
16. Turn the green knob back 1/4 turn.  It should be on solid.