My old fill valve shot a geyser all over the floor when I lifted the tank lid, so I bought a replacement (PlumbPak Keeney 1B1X) at Lowes. I don't see any leaks, but when the float rises to the top, the fill valve hisses for a few minutes. Everything I've found about hissing fill valves says to it's time to be replaced, which is clearly not what I want to hear.

This is the old one:

What I started with

And this is the new one:

The replacement

I've adjusted the two gold screws on the top, as well as the large plastic screw on the side. The top one adjusted how high the float went, but the other two didn't seem to do anything.

Also, the clear tube seems odd, since it wasn't there in the old install, but that's what the (extremely limited) instructions said to do.


For this type of valve it is normal for there to be some hissing as the tank is nearly full, because as the float rises with the water level, it is gradually closing the valve. The hissing is the sound of water movement through a nearly-closed valve. If you can trigger the same sound by flushing and then manually raising the float so the valve is nearly closed, then that's your issue. If water is leaking out of the top of the fill valve, you have a different problem (a defective valve).

Assuming the sound is just continued operation of your fill valve, then it's not right for this to take minutes - should only be 15-60 seconds of hissing before the fill valve closes completely. It's possible that the valve is allowing too much water to enter the tank, and that water is then running down into the bowl through the overflow (the tall pipe in the center of the tank). In that situation, you're continuously adding water to the tank while draining it away. This can lead to constant running, potentially hissing, and of course lots of wasted water.

To correct this, turn the screw at the top center of the fill valve clockwise. This will cause the ballcock to shut off the fill valve at a lower level. You should aim to have it stop filling the tank at about 1/2" below the overflow. You can make this adjustment while the tank is filling after a flush, and flush/refill once or twice to tweak.

Also, the clear tube is correct. This tube is what provides water to directly re-fill the bowl after you flush. In the first picture, you can see the nipple to which a similar tube (usually opaque and thinner) would be attached. It's at the top of the fill valve, the black plastic section, and pointing to the right. The reason water splashed everywhere when your tank was previously opened is that there was no tube attached to guide this water into the overflow (as you've done with the clear tubing in the new install).

  • I can trigger the same sound as you described, but water dribbles out of the top right before the hissing sound. Does that mean the valve I bought is defective? – Dan H Jan 27 '16 at 21:35
  • Possibly. A small dribble (at a specific point when the valve is closing) isn't a big deal and it's not inconceivable that it could be designed to do that, but it might be a defect. If the leak continues after the valve should be closed, it's definitely a defect. Where is the water dribbling from? – Shimon Rura Jan 27 '16 at 22:00
  • It seems to be coming out of the top a bit, but mostly around the seam just below the three screws around the perimeter, but it doesn't continue like the hissing. – Dan H Jan 27 '16 at 22:13
  • I adjusted the top screw counter-clockwise to let the float rise higher and it still hisses for a good minute, but it finally stopped hissing at last. Thanks for the assistance. – Dan H Jan 27 '16 at 22:32

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