After replacing refill toilet runs at times

I'll try to explain the best I can without knowing the names of the actual parts. I had to replace the refill valve in the toilet tank. The old one had the ball that raised and the water shut off when it got to a certain point. My dad and I put in a newer kind which he said works great. There is no ball and the water raises a piece on the "refill stem" I'll call it. Once it gets to a certain point the water shuts off. We adjusted to the height we wanted and it flushes and refills fine. Howerver ever since this was put in about every 30 minutes you hear the toilet make a filling sound for a few seconds and then it stops. I've watched it and water actually fills the bowl for a few seconds before it turns off. You also hear a pipe "bang" in the basement. None of this happened until this part was replaced. Any ideas?

Thanks
Dawn

Sounds like you have a leak, probably from the flapper valve into the tank. To confirm this, put some food coloring in the bowl. Let it sit overnight, and I'd bet that the bowl is clear by morning. The only way that happens is if it gets flushed out. Replace the flapper valve and it should fix it. Also, check the seat where the valve sits, make sure it doesn't have anything on it - it should be smooth without any pits or debris. If it is, they make replacement seats you can put in. Did you have to move around the chain that pulls up the flapper valve? It needs a little slack, it may have been kinked and is holding the flapper up a little (it doesn't take much). Give it a little more slack, or unkink it. Last, make sure that the fill is to the design height.

The banging of the pipe when it shuts off is because this kind of valve shuts off quickly. Typically much quicker than the old style ones. Water wants to keep moving, and when you shut the valve off quick, anywhere the pipe may not be anchored properly, it will jump. It may be hitting a wall, or against a loose bracket. They make water hammer arrestors that act like shock absorbers to cushion that water column. They work well on washing machine supplies and things like that as well.

Flapper

I agree with Jim about it probably being your flapper allowing water to leak from the tank into the bowl. I put the coloring in the tank instead of the bowl. If the water comes on this often you can make a pencil mark on the inside of the tank and probably see it lower in 5 minutes. Also you probably can see ripples in the bowl where the water is leaking form the tank. It may also be that you have the small refill hose going down into the neck of the overflow. The causes water to continually siphon through the ball cock (fill valve).
In addition to the loose pipe the band could come from the washer on the shut off valve to the toilet being loose from when you closed and opened it.

Flapper

Thanks for the info and I think the flapper is the problem because I can see (very hard to but I see the ripple in the water) but I see water going into the bowl very slowly still after it fills and shuts off. I checked the flapper and the seat and I don't feel any debris so I'll just get a new one and go from there. I had already loosened the chain but it did not help. And thanks for the info about the pipe. I was worried it was something serious. I should be able to track that down with some patience waiting for it to bang.

Thanks for the advice!

Dawn