So... I have installed the new parts this morning, which consisted of injector, piston and stack. I did the injector by itself and had no luck. Then the stack and piston. Comparing the two stacks and the rubber seals, the new rubber seals were nice and round, while the old ones looked quite flat and/or angular. Put in the new stack assembly and it is sucking brine like a champion. Now to figure out how to program it!
Injectors rarely to never go bad. They do block up with rust though which is easy to clean out.
I'm glad to see your new stack and pistons solved the problem, as I knew they would.
The 'manual' that Tom linked to isn't The Manual you should have but it shows how to program the valve. Except they don't change much from the default settings.
You need to have current hardness, iron and manganese test results (manganese is fairly rare and most dealers etc. do not test for it) if on your own well or a non chlorinated community well.
If on city water, use the highest hardness in the entire system. You can get that info from the Annual Report they mail you or on their web site or by calling them. Don't use a test result of your water or your neighborhood's etc. hardness figure. Use the max in the system.
Then go to the link in my signature and come up with your K of capacity for the volume of resin you have (in cuft) and the salt dose lbs that K of capacity requires for a regeneration on average every 8 days and program with those figures.
I you want to, email me and I'll email you a copy of the Clack Manual. qwasluss @ ptd.net