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Plumbing in the Home/shower gets really hot or really cold, but I turn the knob a fraction of an inch



This has been happening since I bought the house, easy 15 years ago. I have a single knob control. I turn it all the way hot to get the hot water upstairs the quickest (the hot water comes from the basement). I then turn the knob a fraction of an inch. It cools down enough to get under it. I f I turn it a little more, bam, it goes cold. Not cooler, just cold. It seems that there is no real middle ground. If there were a mark on the knob, and 9 o'clock was the hottest, then I don't think even this far, but lets say for all practical purposes, by the time I get to 10 o'clock, it is cold. Since I have bought the house, I replaced the internals once, about 5 years ago. It was the little metal ball type control with all the holes in it. I replaced those little washer plug type things for the two holes in the "pipe" itself. I had this problem before I did that, and nothing has changed.

Thanks so much,

Jim L

Hi Jim,
From your description, this sounds like a Delta valve. In my experience, it is possible to miss-install the ball assembly or the washers and springs under them. The little nylon ball has a small nub that is supposed to line up with a slot in the housing as you screw down the retainer ring to hold the ball in place. Is there a positive stop when you go right to left with the handle?

The faucet body is brass and there is usually no problems with that. The only thing that can wear is the ball and the washers & tension springs. The washers fit into small recesses in the brass body of the faucet and have small springs under them to maintain tension against the ball.  The only thing I can suggest is replacement of the ball, seals and the spring/washer assemblies and then careful reassembly.
Good Luck,

Plumbing in the Home

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Dana Bostick


Pretty much any residential plumbing questions. For "item specific" details such as a specific model of fixture, I will need to research and there may not be any useful information available. Note: I live and work in Southern California. We do not, as a rule, use hot water or steam heating systems, oil fired boilers or private water wells so my knowledge in those areas is pretty limited. There are others here on AllExerts that can probably answer those questions better.


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