This is definitely a conundrum: not even our local hardware store could figure this one out! So, here goes:
We have a fairly new one-piece toilet in our guest bathroom that now takes forever to refill its tank! Note that there isn't a problem with the bowl refilling...that fills up fairly normally and rapidly. Also, this is a relatively recent change: this toilet actually used to be the fastest flushing toilet in the house.
Here is what I checked:
- A visual inspection has uncovered no cracks/leaks from the tank portion of the toilet.
- No problems with the flapper valve (we aren't getting plagued with random "ghost flushes", and the flapper appears to be seated well and sealing properly on each flush).
- The water valve is fully open.
- Just for the curious: the other toilet continues to flush normally.
Here's where the puzzle comes in: based on all of these observations and watching the problem toilet in action, it appears that the problem is the overflow tube, which I have never heard of (nor anyone else). The fill tube running from the fill valve is stationed to run water down the overflow tube--as I understand it, this is normal and is what allows the bowl to refill. But when flushed, it takes over four minutes for the tank to fill.
Here is another reason I suspect the overflow tube: it just so happens that the clip holding the fill tube in place over the overflow tube is wearing out. One time when I had the tank cover off and was repositioning the refill tube back in its proper place, on a whim I decided to hold the refill tube outside of the overflow tube, so that it would send its water directly into the tank, and flushed to see what would happen. The toilet bowl and tank filled rapidly--as one would normally expect--and shut off promptly.
What in the world is going on here? I appreciate any serious guesses!