Two-week old Toto Promenade 1.28
Wife complained of "water running" sound. Sure enough I found the fill valve allowing a small amount of water to flow because it apparently couldn't quite close. Faulty fill valve? I flushed and it re-filled and shut off crisply, but an hour later was running slightly as before. I shut off supply to stop the noise overnight and next morning the tank was empty.
No sign of leaking from tank/bowl gasket, just into the bowl. I pulled off the flapper, which looked clean and smooth and not distorted. The rim of the flush valve orifice feels smooth and clean, so the flapper should seal alright. The little float on the chain exerts some upward tension on the flapper, as its attachment to the chain keeps it a little below the water surface when the tank is full.
Toto customer service said they would send me a replacement flush valve.
Before I do that, I thought I'd ask if there is a simpler solution?
I wonder if there is a problem with the filler valve also? I'm used to Fluidmaster valves cycling when a flapper leaks, but not running constantly at low rate. Is it normal for the Toto filler valve to hang up when the water level drops slightly, or might the constant running be because the leak rate equals the fill rate at that water level and the fill valve cannot get ahead of the leak?