I have a Hayward 3020 cartridge filter on a 19000 gal in ground pool. I had to recently replace the bottom and top manifolds as they were cracked, falling apart, and allowing debris to renter the pool. It was a struggle to get the bottom manifold in, but it is snug and in place. When I first started the pump, the pressure was fine at about 15 psi. Eventually, it started to climb up to 35 psi.
This weekend I took every thing apart that I regularly handle, cleaned it all out, lubed all the O-rings, checked the connections on the manifold, and put it all together. When I turned the pump on and cleared the air, It stayed at 10 psi. About an hour later it was at 15 psi. 4 hours later is was at 30, and the flow from the jets was slow, which tells me it's not a bad guage. There is no air in the system. I turned on the booster pump to see how the polaris was moving, and that was running fine. After Turning the pump off and waiting a while, there is still no air in the system, so I know it's pretty much air tight. Although, now when the system is turned back on, the PSI goes straight to 30 rather than a gradual climb.
I know if I take it all apart, it will probably go back to a normal level only to climb back up later.
Please help me! I'm at my wit's end.