s,
I am not even close to being an in-floor cleaning expert... I suggest you look at the link I provided.. I think it is to a kit of parts for your system. It should give you an idea of what you have.
If this were my pool, I would at least pop the lid and see what is in there... Basically, the heads pop up a few at a time and some mechanism rotates which heads are up and which are not. Since I am not a fan of in-floor systems, I would see if it was possible to disable the pop ups and just have return water flowing out of all of them at the same time. I have a Robot I use for cleaning...
On the other hand, if you think you might like the in-floor system, then you might want to see what it would take to bring it back to life. For all I know it might be working right now, but we did not even realize it was there... [emoji14]
Thanks for the update...
Jim R.