White - AA for 7"-8" tanks
Blue - BB for 9"-10" tanks
Red - CC for 12"-14" tanks
Green - DD for 16" softeners, or any size Iron Filters** Tank Diameter - How to Measure and Why It Matters ** Your OLD Injector may look more squared off than the ones in our photos.
The design ( mold ) was changed many years ago, but they all work the same.
Small end goes in first.
Larger end has the "hole" in sides.
Direction of the side holes does not matter.
Push into place until you feel the small end o-ring "locking" into place.
Removal requires pulling out with needle nose pliers ( sometime requiring excessive force to remove ).
If you can't PULL it out, then you can PUSH it out from the Injector Screen side of the Valve Body.
Long but thin screw driver ( phillips head ) and a couple "taps" with a small hammer should get it to pop out.
NOTE: There are different Injectors used with the newer LOGIX controlled Autotrol Valves ( 740, 742, 760, 762, etc ).