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A manifesto on shower temperature control

benholmen.com

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Re: A manifesto on shower temperature control

#41

Post by hulitu »

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...

GNOME argument strikes again.

I don't use the acceleration and brake on my car all the time. I use the doors to enter or leave the car. I use the electric windows when i insert the parking ticket.

Re: A manifesto on shower temperature control

#43

Post by Arrath »

AnthonBerg wrote: post #40
MR4D wrote: post #23

Earlier quoted context omitted.

Now I want one of those for my car!

Haha, probably we want a hinge on the joint between the gas pedal and the curved pin thing it pushes down? And move the pedal back or forward? Or yeah, I love to be super ignorant of the classical Simple Machines and try to work out mechanics like this. I’ve actually had some success with guess-prototyping mechanical contraptions in the physics-sandbox game Besiege: https://www.spiderlinggames.com/ I can also emphati…

These days you muck with the pedal position to throttle mapping, no need to change the mechanism itself.

Re: A manifesto on shower temperature control

#44

Post by Spivak »

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.

Re: A manifesto on shower temperature control

#45

Post by gorgoiler »

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 source is capable of reaching is highly variable and certainly not constant. Higher flow for example reduces temperature as more cold water cools the heater. Heaters also cut out and oscillate as they overload.

Throughout the year the C temperature may also fluctuate by several degrees in a way that can trigger non linear effects in the hot water generator. (This is all assuming you have a just-in-time hot water source of course — more common in Europe than, say, NYC apartment blocks.)

Study the whole system and be prepared for unexpected non linearity everywhere. Heat loss per foot of pipe is a real thing, as is thermal damping of uninsulated tubing, to give two more examples.

If you can model the system then next up, you might try your hand at predicting the weather.

Re: A manifesto on shower temperature control

#46

Post by kccqzy »

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...

That's what I thought too. Why not take the first step to reduce the temperature setting on the water heater?

Re: A manifesto on shower temperature control

#48

Post by thrwawy74 »

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.

Re: A manifesto on shower temperature control

#50

Post by fuzzy2 »

xenadu02 wrote: post #24
retrac wrote: post #17

Ah yes, showers that have frigid, cold, and scalding settings, and not much in the way of warm. This is is usually because the hot supply is under relatively less pressure, going through a tank and more pipes. So, nice and warm means hot is almost fully open and cold almost fully closed, to get an equal mix of both. Very little room to work with. The right flow restrictor on the cold supply will make midway an even m…

In a correctly plumbed system there should not be a significant pressure differential on the hot and cold sides. When done correctly (upsized feed from the utility) with balanced loops or a manifold flushing the toilet shouldn't effect shower pressure or temperature at all. I can testify to that because in our house it works that way. The only time a shower is affected is when filling the large bathtub - which fills…

Even if the pressure does not change, the temperature definitely does. Currently, cold water is basically icecubes blasting out the shower head. Warm/hot water, on the other hand, is sometimes affected by a heat exchanger (district heating) malfunction.
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