[HN Gopher] A manifesto on shower temperature control
___________________________________________________________________
A manifesto on shower temperature control
Author : aarondf
Score : 129 points
Date : 2023-02-01 14:59 UTC (1 days ago)
(HTM) web link (benholmen.com)
(TXT) w3m dump (benholmen.com)
| teaearlgraycold wrote:
| Why does my kettle have a thermometer but my shower does not?
| balfirevic wrote:
| Because you (or your landlord) bought one without it - showers
| with thermometers do exist.
| crazygringo wrote:
| 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.
| anigbrowl wrote:
| * * *
| PaulHoule wrote:
| 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 unless we have a replacement lined
| up.
|
| All of that means that the input temperatures are poorly
| controlled even when the heater is working.
|
| The very large range of mixing ratios helps compensate for
| uncontrolled input temperatures. If the input temperature was
| better controlled (say with a thermostatic function) you might be
| able to calibrate the valves to a user-appropriate range, but
| barring that you'd need to put a thermostat right after the
| valve.
| sokoloff wrote:
| It's obviously your risk not mine, but I wouldn't be
| particularly concerned with descaling a tankless with vinegar
| causing a problem. I'd be more concerned with the uneven heat
| transfer causing damage (by overheating the metal that doesn't
| have adequate cooling from the water [that you're intending to
| heat]) than I would from the descaling causing damage (or more
| precisely, _revealing existing_ damage).
| gwern wrote:
| 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...
| hulitu wrote:
| 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.
| Gordonjcp wrote:
| Thing is, that 90% of the range is going to mean that you and
| I pick a different range from "hottest" to "coldest", right?
|
| So it wouldn't be beyond the wit of man to fit a couple of
| setscrews, possibly accessible by popping the knob off, to
| set the "low" and "high" stops for the thermostat in the
| shower valve, right?
|
| You'd think, eh...?
| aaron695 wrote:
| [dead]
| gus_massa wrote:
| Another problem is the difference of pressure between the cold
| and hot water tubes. It's usually not to much, but I remember
| than in one hotel the difference was so big that if I opened
| both taps normally, I only got cold water. Moreover, the cold
| water entered into the hot water tube, so after closing the
| cold water tap I got only cold water coming from the faucet for
| a while. The solution was to open the hot water tap completely,
| and make a tiny turn in the cold water tap.
| UniverseHacker wrote:
| I prefer cold showers, and have the opposite complaint. Most
| valves are over-optimized for 'normal' shower temp ranges, and
| still mix in a lot of hot water even on the coldest setting,
| which makes taking a really cold shower impossible.
| cuteboy19 wrote:
| Why not simply have two separate valves for hot and cold? It's a
| one time expenditure!
|
| But of course this foolishness has competition: no bidets
| anywhere!
| amluto wrote:
| 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...
| Nifty3929 wrote:
| This would depend on the temperature of your hot water feed,
| which is likely much lower.
|
| It's like having a speedometer in your car that goes to 180
| mph.
| Nifty3929 wrote:
| Also we have body sensors which detect acute over-temperature
| situations and cause us to remediate the situation before
| damage can occur. Usually while screaming something profane.
| amluto wrote:
| In case you have never been in a slippery shower or
| encountered anyone with one of many possible disabilities,
| excessively hot shower water is a genuine hazard. For
| example:
|
| Slow reaction time (you can get burned very quickly by
| excessively hot shower water)
|
| Limited sensation in some part of one's body
|
| Balance issues or movement issues.
|
| Anything preventing one from getting to the control or out
| of the water very very quickly.
|
| A shower delivering 134F water is hazardous and serves no
| purpose.
| amluto wrote:
| I was off by 6 degrees (looked lazily at axis labels, not at
| the actual data). But the OP actually measured the
| temperature. It says, right in the article:
|
| > The minimum temperature was 44.4degF (6.9degC) and the
| maximum temperature was 134.1degF (56.7degC).
|
| So yes, this shower violates the code.
| kccqzy wrote:
| That's what I thought too. Why not take the first step to
| reduce the temperature setting on the water heater?
| Spivak wrote:
| 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.
| NeoTar wrote:
| That's solved by European dishwashers. They take in cold
| water and heat it up themselves.
| PicassoCTs wrote:
| 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..
| Zanovis wrote:
| Quick and dirty solution: find the optimal position for the
| valve(s), mark where they are relative to their base, and open
| the valves to that position each time
| op00to wrote:
| My cold water temperature fluctuates with the outdoor air
| temperature, doesn't everyone's?
| bluSCALE4 wrote:
| 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...
| gorgoiler wrote:
| 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.
| thrwawy74 wrote:
| So we need like a capacitor for hot water at the shower head.
| hnuser123456 wrote:
| 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.
| oakwhiz wrote:
| Interestingly, control valves employed in this way tend to
| wear out very quickly or else they are slow and expensive
| so that they can be made more durable. Anybody working on
| this needs to hit that "good, fast and cheap" triple point.
|
| This is why wax motors are commonly used as valve actuators
| since the only calibrations are the wax mixture, the
| mechanical force applicator, and the thermal resistance of
| various components in contact with each other
| diggernet wrote:
| You don't need a computer, or even electricity.
| Thermostatic shower valves are 100% mechanical, and work
| beautifully. There are models available that will
| automatically compensate for both temperature and pressure
| changes, keeping the output temperature constant.
| standardUser wrote:
| I'm obsessed with showers and also wonder why we are so
| spectacularly bad at making consistently good showerheads with
| consistently good pressure and temperature control.
|
| One issue the author overlooks is that we have minimal control
| over the temperature of the cold water, and this temperature
| fluctuates throughout the year (at least here in NY, not so much
| where I lived in SF). As a result, the range of the dial I use
| changes from summer to winter. There are hot parts of the dial I
| use everyday in the winter that would simply burn me if I used
| them in the summer.
|
| Temperature can even change during the course of the shower! I
| notice this mostly in the winter. I speculate this is due to the
| cold water in my building pipes being used up and then replaced
| by the truly cold water from underground. I once tried to shower
| with that icy water when the hot water went out (just before a
| big trip) and I managed to completely numb my lower body (I did
| not have the fortitude to try and shower my upper body too).
| joezydeco wrote:
| These devices exist. You just don't want to pay for them.
|
| https://www.kohler.com/en/products/showers/shop-shower-trims...
|
| What you have in your shower is a cheaper anti-scald valve that
| just prevents super huge spikes in water temperature when the
| input pressure changes (i.e. your wife flushes the toilet).
|
| Like PaulHoule says, you need monitoring of input and output
| temps to do that. And that's technically possible, but it's
| complex and expensive.
| unethical_ban wrote:
| I feel like a mechanical version _could_ be made which has a
| separate gear ratio for the middle of the operating spectrum.
|
| Alternatively, for the traditional "hot/cold knobs" function, I
| don't see why a third pressure knob couldn't be added.
|
| I could leave the hot and cold knobs turned exactly where I
| want them to be, with some arbitrary number dial helping for
| consistency, and I only have to turn the pressure knob to let
| the water start running.
|
| I shouldn't have to spend $1500 for that.
| retrac wrote:
| A cheap valve between the hot/cold valves and the bath faucet
| or showerhead can provide that.
|
| Unfortunately, single-handle mixer valves aren't usually
| designed to have their output blocked under pessure like
| that. So that's when it starts getting expensive and
| specialized. But with traditional separate hot/cold valves,
| it works fine.
| convolvatron wrote:
| its not really gears? I assume its some kind of bi-metal
| strip. if so, you would just need to change the shape of a
| cam (?)
| c_o_n_v_e_x wrote:
| I feel like this could become the next Swiss watch. Bring joy
| back to showering. Meticulously hand crafted by artisans in
| the Swiss Alps. Features include:
|
| - Polished stainless steel case
|
| - Intricately geared shower control valve with see through
| cover
|
| - High precision temperature set point control
|
| - Compensates for input water pressure / flow to maintain
| temperature
|
| - Comes with unique ID and certificate of authenticity
|
| Obviously it will require annual servicing to make sure
| ensure continued operation. Your smugness will keep you warm
| long after your hot water runs out.
| stdbrouw wrote:
| Huh? Regular thermostatic valves do not provide perfect
| regulation but they do in fact provide a fairly stable output
| temperature regardless of cold and hot water temperature, by
| entirely mechanical means. I have a cheap IKEA shower control
| and output temp is stable for the full duration of my shower
| even though cold nor hot water supply is stable due to a shower
| drain heat recovery unit.
|
| The article is mainly about wanting the regulation to be
| between 35-45C instead of 15-55C.
| achenatx wrote:
| you can change the top end by lowering the temperature of
| your hot water heater. We have ours set at 120. Using a lower
| hot water temperature is a way to give you a wider range of
| useful temperatures.
|
| In texas during the summer we often take showers with no hot
| water (or very little hot water).
| trynewideas wrote:
| This isn't always feasible depending on the location, age,
| and type of water heater, and how many things with
| different temperature needs are connected to the same water
| heater.
|
| A tankless water heater with a feeder pump, dedicated to
| bathroom use and with a bathroom-installed remote control,
| makes this trivial. It's probably also more efficient,
| easier to use, and (vs. thermostatic valves) about as easy
| and maybe also cheaper to implement than any fussing with
| valves.
|
| A 30-year-old tank heater in a basement that needs a wrench
| to adjust a temperature that won't meaningfully change in a
| 2nd-floor bathroom for another half-hour, and also has to
| serve a dishwasher and clothes washer that might also run
| at higher temperatures at the same time, can't swing this
| as easily, or at all.
| Someone wrote:
| > you can change the top end by lowering the temperature of
| your hot water heater. We have ours set at 120
|
| I'm not sure that's a good idea. 120F is in the danger zone
| for Legionnaires' disease. https://en.wikipedia.org/wiki/Le
| gionnaires%27_disease#Preven...:
|
| _"Keep water temperature either above or below the 20-50
| degC (68-122 degF) range in which the Legionella bacterium
| thrives."_
| adamj9431 wrote:
| Interesting. On the other hand, when bringing a newborn
| home from the hospital, the take-home literature
| instructs new parents to turn the water heater down to
| 120 F to prevent risk of scalding.
| stdbrouw wrote:
| I wouldn't worry about it. Almost every modern boiler
| will bump up the temperature to 60C / 140F once a week to
| prevent Legionnaire's, may even be a mandatory feature
| depending on where you live.
| exmadscientist wrote:
| The "right" way to do this is a thermostatic mixing valve
| at the water heater output. This lets you keep the tank
| at 150degF (or whatever) but the output gets mixed down
| to 120degF (or whatever). It also gives you an
| effectively-larger tank which can be very useful in
| certain cases.
|
| Of course, you might say, why not put the thermostatic
| mixing valve at or in the shower, which also works pretty
| well!
| Kim_Bruning wrote:
| Are cheap thermostatic shower mixer controls not so common
| outside middle-of-europe?
|
| This is the one with one grip that lets you set the
| temperature, and the other sets the flow rate.
|
| It'll (try to) hold the output temperature steady even if the
| input temperature varies a bit.
| nicd wrote:
| In my experience (US), they seem to be uncommon in
| residential properties. I've seen them in many hotels,
| though.
| klondike_klive wrote:
| I always wondered if Britain turned out more than its fair share
| of safecrackers because of our traditionally crappy shower
| controls and how a sixteenth of a turn meant the difference of
| maybe 30 degrees of heat.
| AnthonBerg wrote:
| I have a kind of powerful dirt bike. People put "throttle cams"
| on them for this same reason. Usually you want small adjustments
| within the lower range of power. When you want the majority of
| power you usually want close to all of it.
|
| Throttle cams are basically an off-center circle. At lower
| throttle you're pulling a smaller circle and the throttle moves
| less. Then when the throttle is opened up you're pulling a bigger
| circle.
| MR4D wrote:
| Now I want one of those for my car!
| AnthonBerg wrote:
| 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 emphatically recommend just getting a Husaberg
| 550, 570, or 650 %D
| Arrath wrote:
| These days you muck with the pedal position to throttle
| mapping, no need to change the mechanism itself.
| fy20 wrote:
| If you car has an Eco or Power or Sport mode this is probably
| what it does. On my Toyota, Power mode makes the accelerator
| more sensitive and Eco mode makes it less sensitive (which is
| great for snow). Flooring it is the same, regardless of the
| mode.
| retrac wrote:
| 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 mix, and so more of the dial is useful. Very much worth the
| $10 the next time you have access to the plumbing.
| xenadu02 wrote:
| 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 much faster than in most homes because it
| has a very large feed but that's the tradeoff since there isn't
| enough volume from the utility in that one case. Otherwise
| people can flush toilets, use the kitchen sink, wash clothes,
| etc and showers are not affected whatsoever.
|
| Another factor is insulation - even many modern homes don't
| insulate the hot water pipes so even with an instant hot water
| heater that responds quickly you still have to pay the lost
| heat cost of warming the pipes and everything the pipes touch
| before the temperature fully stabilizes. This is a cost-saving
| measure - there is no reason the pipes couldn't be insulated.
| If you throw in a recirc pump then you can have instant hot
| water at every tap with very low energy cost.
| fuzzy2 wrote:
| 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.
| TheChaplain wrote:
| Reminds me of the time I went to England, ended up in a cheaper
| hotel with a wash basin that had two taps on each side, hot and
| cold.
|
| Although it was a real pain, what really shocked me was the
| carpet floor in the shower room...
| Arrath wrote:
| > + 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!
| standardUser wrote:
| I always end my showers with _cool_ water because it works
| wonders for preventing dryness and itchiness on my skin. I use
| actually cold water to rinse my scalp.
|
| This is all very different than a shower with _no_ hot water
| mixed in whatsoever. Deepening on the climate and season, water
| that cold can cause physical harm. In other words, I 'm betting
| most of these "cold showerers" are actually use cool water, not
| anything as dramatically cold as they might want us to infer.
| wolfram74 wrote:
| I actually find cold showers in the middle of the day quite
| life improving during the summer months.
| deathanatos wrote:
| 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.)
| pc86 wrote:
| When my wife and I met she lived in an apartment with an
| amazing shower. The pressure was good but the temperature was
| fantastic. I had never had an apartment shower with water that
| got so hot. I barely even went half-way on the knob before I
| was turning it down. I asked about it and her response was "oh
| yeah I complained to my dad and he looked at the heater, there
| was something on it that he broke off." Turns out there was
| some piece of plastic or something put on by the landlord to
| limit the top temperature of the water, so he took it off.
|
| It didn't keep the hot water from running out but when you had
| it, it was great.
| waste_monk wrote:
| >(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.)
|
| When we changed from instant hot water to water tank + heat
| pump, the guy said the tempering valve was a safety thing (IIRC
| ours was set to 60 degrees Celsius by default, but could go up
| or down about 10 degree either way). That is, if you
| accidentally step in the shower with only hot water on you'll
| still hurt yourself but the damage will be limited to "strong
| profanity and aloe vera" instead of "you've won a stay in the
| burn ward".
|
| Although saying this, I did a quick bit of research and found
| that 60 may still be too high [1]. I have an IR thermometer so
| I think I'll measure the temperature of my shower (after any
| loss from pipes etc.) and see if the tempering valve needs
| adjusting down.
|
| [1] mild nsfw - image of scalded foot
| https://whywait.com.au/a-serious-hot-water-burn-occurs-in-on...
| yehudalouis wrote:
| Just add a gear affixed to the handle, and then a second gear
| mated with that, and find the gearing ratio that allows the
| granular/sensitive inputs you want.
| russellbeattie wrote:
| The amount of water wasted waiting for the water to warm up must
| be astronomical. In my place it can take three or four minutes of
| the water running to get warm - if not longer - and I don't think
| that's atypical.
|
| Multiply this by 7 days a week by everyone who showers in
| California alone and it seems like an issue that should get some
| serious attention.
| achenatx wrote:
| I have one of these grohe thermostatic valves. You can set the
| temperature and then use a push button to turn the shower on. The
| temperature is always set correctly as the on/off is separate
| from the temperature control. A majority of the range of the dial
| is usable. We still use cold water for cleaning the shower, or
| when you want a cold shower. During the shower, I have it set to
| hot, then slowly turn up the heat. This uses about half the
| dial's range.
|
| The big difference is the grohe costs $500 while a standard
| builder grader valve might be $50.
|
| https://www.build.com/product/summary/1391570?uid=3279009&jm...
|
| <<How does a Grohe thermostatic valve work? The thermostatic
| valve mixes the hot and cold water to your pre-selected
| temperature and reacts instantly to any changes in the pressure
| or temperature of the water supply by re-adjusting the mix of hot
| and cold water.>>
| brmgb wrote:
| I have thermostatic valves here which costed me something like
| 80EUR.
|
| It's not as fancy as the Grohe. It looks like a classic two
| knobs system except the right one controls temperature with
| gradation in degrees while the left one controls flow.
|
| Better temperature control doesn't have to cost an arm.
| scottlamb wrote:
| I have a Grohe thermostatic valve which came with the house.
| It's somehow broken such that you can't get the water as hot as
| advertised unless the dishwasher is running (?). And it's
| installed behind tile, so we can't just get a plumber to come
| in and replace it; we have to also line up someone to re-tile
| the shower immediately afterward.
|
| We also have a pair of Grohe sinks. We had to replace all four
| expensive, proprietary faucet hoses because they'd ruptured.
| And then a couple more. It turns out they're short enough that
| it's hard to install them without kinking, and that eventually
| causes them to rupture.
|
| I'm not a Grohe fan.
|
| (It also takes several minutes for the water to come to
| temperature in that particular shower, though it's only about
| 10 feet away from the water heater. I think the sink fixtures
| are affected too which suggests it's not all the shower valve's
| fault. It might be that we have pipes that are indirect and/or
| way too high-capacity, such that the total volume of water to
| drain between the water heater and the bathroom is excessive,
| and this is particularly obvious when using a low-flow shower-
| head.)
| sintezcs wrote:
| I also have grohe thermostatic valve and enjoy it a lot! Worth
| every $ spent.
| jjk166 wrote:
| This is a result of the valve construction - you have a cold
| water pipe and a hot water pipe coming in, and the knob/lever is
| connected directly to a single valve that controls volumetrically
| how much the flows mix. This arrangement is both cheap to
| manufacture and easy to install and repair.
|
| Adding proportional control isn't too hard. Certainly an easy
| option would be actuating the valve electronically and just using
| an encoder in the knob to control it digitally. There are a lot
| of advantages to this, such as being able to automatically comp
| for actual water temperatures and customizing settings for
| personal preference, but it's understandable that people might
| feel uneasy about a cheap electronic device in close proximity to
| the water they are in. I'd point out that this hasn't stopped us
| from putting things like lights in our showers which by necessity
| draw much more power, but some may still be concerned. More
| likely it is the lack of experience with electronics that valve
| manufacturers and plumbers have that make them hesitant to
| change.
|
| For a mechanical solution, you could transmit the torque via a
| gearbox instead of a direct shaft. Switch gears to get higher or
| lower resolution control. You can even have a single set of gears
| with variable diameter sections to have higher precision in a
| fixed subsection of the range. Unfortunately this would not allow
| for easy adjustment for an individual installation, nonetheless
| different people using the same shower. The increase in
| manufacturing cost and installation complexity would probably not
| be huge, but in such a high competition commodity market it would
| be noticeable.
|
| But solving the real issue, a lack of fine control in the
| important range, is actually much easier to solve. Just make the
| handle on the knob longer/larger diameter. Especially if you just
| want to modify an existing installation, attaching an 18 inch
| handle onto the existing knob is something just about anyone
| could do in a few minutes. For precise control, grip it on the
| outside, for fast large changes, choke up on it. For the OEM, a
| design with a long handle is pennies more expensive to produce at
| scale, easily justified for even a very small competitive
| advantage. Maybe some people really like the aesthetics of a
| small handle, but I've never once heard someone complain a shower
| handle was too big. I still think the electronic controller
| option is better, as you can deal with other shower temperature
| control problems like the long heat up times of the pipes and the
| variable ideal water temperature at different points in the
| shower, but the perfect can be the enemy of the good enough.
| Frankly it's just weird that I can't seem to find a shower handle
| longer than about 6 inches available for sale right now in a
| quick google search.
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(page generated 2023-02-02 23:00 UTC)