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A manifesto on shower temperature control

benholmen.com

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Re: A manifesto on shower temperature control

#51

Post by NeoTar »

Spivak wrote: post #44
amluto wrote: post #25

Yikes, the max temp is 140F. That’s dangerous and has been a code violation for a long time, for good reason: https://www.pmengineer.com/articles/94780-upc-continues-to-e...

It really shouldn’t be, at least for homes where the owner gets to choose. Being able to set you water temp extremely hot makes your hot water last longer because the comfortable water temperature is say like 70% cold, same applies for laundry. Also consumer dishwashers perform much much better with higher hot water temp.

That’s solved by European dishwashers. They take in cold water and heat it up themselves.

Re: A manifesto on shower temperature control

#53

Post by aaron695 »

gwern wrote: post #10
PaulHoule wrote: post #2

I think the current ones are the way they are because the input temperature is not well controlled. I live in an old farmhouse where the cold water gets really cold in the winter and for years we've had a tankless water heater that has never worked that well but lately has gotten full of scales. We haven't tried descaling it because we're concerned that we'll kill it in the process of descaling it and won't try it un…

Or to put it another way: Spolsky said that users don't use 90% of the features in any app; unfortunately, they each don't use a different 90%. You don't use 90% of the shower faucet ratio range; unfortunately, each house doesn't use a different 90% of the ratio range...

[dead]

Re: A manifesto on shower temperature control

#54

Post by hnuser123456 »

thrwawy74 wrote: post #48
gorgoiler wrote: post #45

As a friendly heads up to anyone exploring this space — temperature control is a complex dynamic between many components, chiefly the mixing valve, any local thermostatic dampers in the valve (rarer, but definitely a feature of high end mixers), and the source of hot water itself . Mixer taps are not simply mixing hot water at temperature H and cold water at temperature C. The temperature H which your hot water sourc…

So we need like a capacitor for hot water at the shower head.

Or just active control? Set a desired output water temp, and let a computer constantly fiddle with the valves slightly to keep the output constant. Monitoring the current temp of the input lines would help but not be necessary.

I mostly don't like that every few minutes, I have to turn down the cold water a smidge, as fresher colder water from the ground comes up through the pipe. My shower has two valves for hot and cold separate, so I turn the hot water all the way on, then add just enough cold water to achieve human shower temps at full pressure.

Re: A manifesto on shower temperature control

#55

Post by crazygringo »

teaearlgraycold wrote: post #49

Why does my kettle have a thermometer but my shower does not?

Because your kettle is electrically heated but your shower mixes hot and cold mechanically.

That said, you can pay $$$ for an electrically controlled shower with a thermostat. And also worry about the electronics and motor breaking at some point.

Re: A manifesto on shower temperature control

#56

Post by PicassoCTs »

Not on the screen, is that pipes are a non linear heat regulation plant. https://en.wikipedia.org/wiki/Plant_(control_theory)

Means, demand for warmth is not fullfilled, until the heat has warmed up the pipes, and then its over fullfilled, to the point you regulate towards. Same goes towards the other direction. Cold first cools down the pipe before becoming fully cold..

Re: A manifesto on shower temperature control

#57

Post by bluSCALE4 »

I'm actually installing a thermostatic valve today to go with a recirculating pump I have setup on an electric heat pump water heater. I'm going to be installing it exactly like this guy with an expansion tank. Does anyone see a problem with this layout? Apparently, his doesn't work.

https://www.amazon.com/review/R3NQCKZCEQLLLC/ref=cm_cr_srp_d...

Re: A manifesto on shower temperature control

#58

Post by wolfram74 »

Arrath wrote: post #8

> † The author acknowledges the recent trend of "cold showers" and considers them (a) a trend, (b) undignified, (c) a waste of some life-sustaining solidary time. Hear, hear!

I actually find cold showers in the middle of the day quite life improving during the summer months.

Re: A manifesto on shower temperature control

#59

Post by deathanatos »

On a FIRST robot, we needed something similar. There's "full reverse", "full forward" and "I need fine control", and the original mapping of joystick to wheel motors was linear. It didn't work well for "fine control". We ended up with motor = joystick³ (or some other odd, greater than 1 power; it might have been ⁵). Then you fix, via coefficients, the endpoints of the equation such that the lowest joystick value hits the full-reverse motor setting, and vice versa for forward. The exponent dampens the curve near zero, so there's more "joystick space" spent on the very slow speeds for the fine control, but the operator can still ask for max speed if they want it.

(With joysticks, you also have to deadzone the middle, as "operator has centered the joystick" will sometimes report joystick values of 1 or -1, instead of 0. Or buy a better joystick.)

I'm not 100% sure I'd apply this to a shower: max hot on my shower is hot, I don't usually ever want it. And I wouldn't want to scald someone.

For a long while, our shower was not the typical tiny goldilocks zone surrounded by ice and lava: … it never really got above "lukewarm", even at max. We had the shower valve replaced and it works better now. (And, apparently, as I learned, there's a mixing valve at the hot water heater: i.e., the hot to the shower is not direct from the water heater, like I had imagined. We raised the temp there, slightly.)

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