Toilet with a new flush valve is leaking down. tank leaks down about two inches in about ten minutes and opens the fill valve. thinking it is a bad flapper, I replaced with a new one. no change.
Thing is, if I turn off the water so that the fill valve does not open the thing leaks down about three inches and then stops. No more leaking. I checked the fill pipe just above the stopping point and there are no holes in it.
Is it possible to have an internal leak in the wall of the porcelin tank that leaks internally to the connection between the tank and the lower unit? that seems unlikely but I can't think of any other possiblity It is definitely not leaking anywhere externally
Or is that slight reduction in head pressure enough to stop the leak. That doesn't seem likely. There is still six inches of water in the tank when it stops.