Help!!! Removing Multiport Valve

Bit of history. Bought the house (from a co-worker) 4 yrs ago. Inground 24,000 gal concrete pool built (as far as we know) around 1986-88. Think the Tagelus TA-60 sand filter w/ multiport valve is original. Have done everything maintainence-wise myself (self-taught thanks to sites like this!). All markings on filter are illegible. Have original "manual". Not much help.
Sand needs to be changed. I know the previous owners changed it about 5-7 yrs ago. At the time they changed it, I worked with the wife (not speaking to her now). The did it themselves so I know it can be done. I remember her saying what a pain it was to get their hands inside to pull out the old sand so they had to have taken at least part of the valve off. I'm not sure if I have to take off the entire valve to get to the sand inside the filter. I unscrewed the 6 screws on top & took off that part & the only thing I found was the spider gasket (intact) and I can see partially into the valve itself (no sand visible). Tried to move parts inside...nothing. I disconnected all 3 hoses from the bottom portion so I could remove it but cannot get the entire valve off the top of the filter. I'm not sure if it's just supposed to "lift" off or screw off. There is no other spot to disassemble so I assume that I have to take the entire thing off. Won't budge. Sprayed lubricant on it and figured no matter what, the safest thing would be to try to twist it. Afraid of the pipe shifting and breaking the laterals.
Am I wrong in assuming the valve even will come off the filter....if not, how would you replace a faulty valve w/o also replacing the filter.
Any advice???? HELP!!!!!

Welcome to the forum.
From what I see by doing a search on that filter you need to remove the collar to take the entire valve assembly off the filter. Sounds like you already got the collar off. The 6 screws you mention are for the valve assembly itself, to take it apart. That collar I mention scrunches the valve assembly to the filter body. Since you already have the pipes removed, once that collar is removed the valve assembly should lift off the filter body. Probably just stuck so try twisting it. No threads or anything magic. Looks like the Hayward filter I have.
Even after 7 years there should be no reason to replace the sand. I'm on the 9th season. Only reasons to replace sand should be if you really gunked it up somehow, you suspect damage to the laterals or other components inside the filter, or you suspect the wrong kind of sand was used last time it was replaced.
I'm not familiar with that specific filter so if anyone has more info please chime in.
Al

Thanks for the reply...will keep trying to twist it off.
I'm replacing the sand for a number of reasons. The original owners had used Pristine Blue. I converted back to chlorine because I didn't like the way the water felt. It always felt slippery & even scummy. We also have a lot of trees in & around our yard which brings more bugs, pollen, etc. I also have been getting a puff of white cloudy stuff (not sand) coming back into the pool when I turn the pump on. It doesn't matter if I've just backwashed or not. Can only surmise that the stuff coming in is dirt that is not getting filtered out. I've read & heard both sides of the argument on how often the sand should be changed. Just figured if I do it this time then at least I'll know that it was done right and can basically start from scratch. If I can't get the assembly off I'll either have to call the pool company or give up. I'm one of those people that tends to want to take everything apart just to see how it works! I also don't give up that easily but what was going to be an afternoon project is now going into a couple of days. It's hot here right now but the pool doesn't look too inviting since I haven't been able to run the filter for a day or so...
Jill

Sorry, I didn't respond to your question about how I got my valve off. It did screw directly into the fiberglass tank. The three pipes into the valve were connected by unions so I simply unscrewed the unions. When I couldn't get the valve to budge I hit one of the pipes with my hand so hard the pipe broke off at the valve. I was able to remove the screw in connection and repair that mistake. I tried with all my might to unscrew the valve and couldn't get it to budge. Next, I took a hammer and tapped the valve in a couple of places where I thought it might help to loosen it. I put a piece of cloth between the valve and the hammer. I thought I might break the valve, but luckily it held. After I had tapped it several times in two places, I tried again to unscrew it and it did unscrew. I removed the sand with a tool that hooks to the garden hose that my pool store loaned me. I checked internal piping and laterals and I put in 350 lbs of new sand. When I attempted to put the multiport valve in with teflon tape and teflon paste and hooked it up it was leaking pretty bad. I pulled it out again and tried more tape and paste, but this time it blew out when I turned the system on. I took the valve out again and noticed that some of the threads on the valve were actually broken and the threads in the fiberglass were kind of mushy. I tried to seal it with plumbers goop, but that didn't work. I used marine grade epoxy from Lowes and so far it has been holding at least three days and looks like it will continue to hold.