Why does such a small turn of the hot water faucet in the shower result in such a drastic change in temperature?

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Why does such a small turn of the hot water faucet in the shower result in such a drastic change in temperature?

In: Engineering

3 Answers

Anonymous 0 Comments

It is a valve. You are lining up a hole with the supply pipe for hot water and a relatively small movement can result in a large relative change in that aperture.

Anonymous 0 Comments

I would also add that the valves are typically threaded, like a screw. However, where screws usually have a very fine pitch (i.e., there are lots of threads on them–think about how long it can take to manually drive a screw into wood or the like!), a valve in your shower or faucets is a very steep pitch. You know this, since it takes less than one full rotation of a faucet to open the valve fully. Therefore, even a slight adjustment is moving the internals of the valve a significant way toward being fully open for one temp or another

Anonymous 0 Comments

It’s a dial that always sits at 100% pressure.

At one end, it’s 100% hot. At the other end, it’s 100% cold. In the middle, it combines the two, but the volume of water passing through is the same.

Let’s say the cold water is at 5°C, and the hot is at 50°C. Body temperature is 38°, and a comfortable shower is around 40°.

This means that you’re mixing at about 80/20.

Mix at 70/30, and the water drops 4°, below body temperature. 90/10, and you’re at 45°, close to burning your skin.

So the comfortable range is quite small. Any change moves you to either side of it rather quickly.