Hi Livebetter,

I would ask yourself this: How much China/crystal will you be washing? If you're like most people, it's not a lot, so keeping your dishwasher hooked up to the hot water is not a bad thing.

Like you said, either way is correct, and only you can answer which one you want.

Here is a link that might be useful: My Blog

It is not about fine china or crystal but about energy consumption vs wash times.

People that can afford Miele DWers can afford the extra electricity but isn't one of the reasons to buying such a superbly engineered appliance low engergy use?

Same with other German luxury applainces like Liebherr.

Unless you have a very short pipe between your water heater and the machine and/or run the tap until hot before EVERY fill in the cycle, it doesn't matter much. The machine doesn't use much water and will heat whatever it receives on its own anyway. Depending on your circumstance, internal heating may take a little or a lot longer.

I do not understand the manual's sentence about "gentlest washing of china and crystal". The machine will heat the water to whatever the cycle's target is anyway. Everything is exactly the same except for cycle-timer waiting a bit longer to come to target heat. What does "gentle" have to do with anything?

Surely they wouldn't print that if there wasn't a reason. What am I missing?

@asolo, I think it's because the china setting temp would be lower than the hot water heater temp (I know I read that somewhere just can't think of where). Therefore, if you feed the machine cold water it will heat to a "gentler" temp for china.

Thanks, but still I don't see the connection with cold/hot supply. If the chosen cycle has to heat the water at all, wouldn't the cycle-limit itself control the temperature peak...."gentler" actually just meaning "lower"?

I assume that a lower temp is gentler on china. I assume from this that too hot water is not good for china so in order to get the lower (gentler) heat you need to start with cold water, otherwise, it would be too hot coming direct from water heater.

I'm making assumptions here. I was hoping someone on the forum would have a greater knowledge and would tell me if cold was a better option and why. Otherwise, I'll leave it connected to the hot water.

Potentially -- if it draws hot water warmer than it needs for china -- then its stuck with that. If it draws cold water instead, it can heat to a lower "just-right" temperature for china's gentler cycle.

Does the Miele DW manual give the water temperatures it uses for these various cycles?

"...was hoping someone on the forum would have a greater knowledge...."

There's two of us, then.

I can see "gentler" meaning not starting with a jolt of really hot water. But, jeez, everybody knows about the temperature drop upon entry. And Mieles have SS interiors. The heat-bleed from that acting on the small amount of water the machines now use must be tremendous. I can't imagine a thermal "jolt" to any china or crystal from this source -- unless someone really wants to split hairs about it.

So....OK you Miele owners.....run your tap hot then trip your machine's cycle to allow the fill to begin. When you hear the fill-solenoid close, open the door and feel or measure the water-temp and compare that with your tap-hot.

While I'm writing this stuff, I'm assuming we're talking about minimum temps of ANY cycle being 115-120F for the target temp. If we're talking about, say. 100-105F -- where no DW detergent works worth a nickel -- then I need to drop out of the discussion.

Well, I'm a KA DW person, not a Miele DW one, so I'm not sure...

But according to a current KA manual, its SaniRinse option "Increased the main wash temperature from 105F (41C) to 130F (54C) and the final rinse from 140F (60C) to 155F (68C)."

Not sure if these temps are similar for Miele DWs; I don't see any other water temps given in that PDF.

@chac mool...

Are you saying that a current KA DW has a "main wash" temp of 105F unless "SaniRinse" option selected? Did I get that right?

Sort of.

Here's the owner's manual PDF, courtesy of AJ Madison. The quote above was pasted from top of page 9, but temperatures are also mentioned (twice) in lower half of page 8.

Looking now at the manual for my older KA KUDE70FVSS DW, I see they didn't mention a "main wash" temp for that model, only that SaniRinse raises temperature in the final rinse to ~155F.

Didn't check Miele's DW manual, having been frightened off by trying to make sense of my Miele Speed Oven manual... I recognize that might be more to the point.

Here is a link that might be useful: KA KUDE70FXSS Owner's Manual PDF

@chac mool....

Thank you VERY much for this. I see this temperature notation for two cycles....and I am astonished to learn of it. You've REALLY rattled my cage.

For high-temp scrub cycle it says: "Raises the main wash temperature from 105F (41C) to 120F (49C)."

For sani-rinse cycle it says: "Increased the main wash temperature from 105F (41C) to 130F (54C) and the final rinse from 140F (60C) to 155F (68C)."

These are the ONLY mentions of any temperature in the manual. I don't know how those lines can be read other than to indicate "normal" DW operating temperature is 105F unless special cycle selected.

I had no idea things had gone this far. No DW detergent works worth beans at 105. In hard water, it may not even dissolve. No wonder people are complaining about their dishes not getting clean and their detergent not working like it used to. First no phosphate in the detergent....now, no heat in the damned water? Whoa!!!!

And obvious obfuscation in the manual! From the drawings in your PDF, it appears this KA machine is very similar to my new Whirlpool. My manual is worse than yours. It says in one place under option selections that "sani-rinse" raises the temp in the final rinse to 155F. There is no other mention of any temperature anywhere.

My Miele Diamante is connected to the Hot Water line, and I usually run the hot water at the sink for a minute before turning on the dishwasher. I use the Pots/Pans mode or the Normal mode. I also know that at the local Miele gallery location (Boca Raton FL) that they have all their running units connected to hot water, and they use the China mode almost every day, where I only use it 3-4 times a year (holidays).
I know that in my Diamante manual it says something about connecting it is recommended to connect it to hot water, but cold water can also be used, through the wash times will be longer.

asolo,

There is a third mention of temperature, in the manual above. Notice the double asterisk (**) notation above the Option Selections table on page 8 (above the high-temp scrub cycle option). Referring to estimated wash times in the Cycle Selections table, it says "This is the approximate cycle time obtained with 120F (49C) hot water available at the dishwasher. Increase in time results from low temperature of the incoming water."

So water temperatures may be 120F (an approximate hot tap water estimate?) during washing. Evidently they may drop to 105F as well, I guess; in that case "normal" DW operating temps may range between those two numbers.

I'm not sure if this is a recent change in water temperature (compared to my older KUDE70FV model), or just new and more accurate information about what the temps are inside there.

Also, this says nothing much about whatever Miele DWs do.

FWIW, I'm not having any problems with cleaning from my (~year-old) KA, though I use its SaniRinse option routinely.

Yes, the normal wash temp on many new Whirlpool, Kenmore and KitchenAid dishwashers is indeed 105F. I was a little ...surprised... by that as well. Especially, since most European dishwashers will still wash at 120F when using the EnergySaver cycle.

Livebetter, you already figured it out. The theory is that the C&C cycle washes at lower temps than most water heaters are set at. So if, for example, your water heater is set to 120, the incoming water temp at the dishwasher is still higher than required for the C&C cycle, which, in Europe, washes at 105 to 118F. However, I did a test myself once and can confirm that, even with 120F entering the dishwasher from the first drop, the temperature drop is so great that one ends up with basically cold water after a few seconds of recirculation.

As a guideline, I'd suggest downloading a Euro Miele manual. They have all the temps and times in them and you can, kind of, see how much time and energy you can save by connecting to hot water - although cycle between US and Europe are different, as I understand.

Alex

Here is a link that might be useful: Manual

@fauguy, is it necessary to run the water at the sink first? Won't the Miele increase water temp accordingly? If it can heat cold incoming it must boost not hot enough hot incoming? My manual doesn't say hot or cold is preferred. Although I noticed the manual that @whirlpool trainee linked says cold is recommended unless they have an affordable hot water source (ie. solar). Obviously different in Europe than here. My manual does say that times quoted by the machine are based on cold fill.

@whirlpool trainee, thanks for the info. I did go through the cycle information in your link.

I ran my first load last night on normal. I was surprised how warm my granite counter got above the machine. I never noticed that before with my KA. I got the sense it was quite warm inside the machine.

Everything came out sparkling clean and dry. When the machine signalled the end I cracked the door open for around 10 minutes. There was minor residual moisture on plastics and some in recesses like mugs. I was happy with the level of dryness as I opted for the Optima over the La Perla and was worried things would not be dry enough.

I guess we're saying that heat loss into the machine should bring the temp down to a more acceptable level for china/crystal.

@whirlpool trainee....

"Yes, the normal wash temp on many new Whirlpool, Kenmore and KitchenAid dishwashers is indeed 105F."

I am still reeling from this "discovery". All of a sudden I can understand the frequent reports of poor cleaning, undissolved tabs and visible granular residue being left upon completion of cycle. From my own experience, I am suspecting close association.

I run all of my cycles with a boost which, I know from manual measurement, gets me to 120+ so I haven't noticed a difference. However, when my previous machine's performance dropped off and I diagnosed failure of the element to add heat, the measured water temp was 100-107. Nothing changed but the heat and performance went waaay down -- and this observation with zero-grains soft water. With hard water, I can easily imagine additional symptoms.

Seems to me very similar to what they shoved down our throats with clothes washers a few years ago.

i can predict the future.
DW's will be connected to cold water only.
Since DW's use little water this should be easy.
Come back in a few years: this will be how they work. Cold water only.

In the meantime, confusion prevails.

I know someone who has had one of these "newfangled/crippled" dishwashers for some while. He recommends Finish tablets, or Powerballs or whatever, and reports that the machine cleans quite well at the lower temperatures (and longer cycle times). As I recall he primarily uses the sensor-wash cycle, which may increase the temp, or not, depending on load conditions. Enzyme formulations are likely the performance key. Very high temps can be detrimental to enzyme action. Kenmore washers that touted their Enzyme Soak cycle back in the day directed cold or warm water be used for the soak, never hot.

My dishwasher has been effectively connected to cold water for 6+ years, works fine.

@davidrol.....

I wouldn't resent such a change if it came. Mfgr's can do whatever they want...always have. I expect that.

What I DO resent is the intentional obfuscation and hiding of basic information ANY purchaser/operator of these machines should be aware of and would normally consider at point of purchase. As with clothes washers earlier -- and ongoing -- they don't want you to know or consider. All they want is their damned Energy Star rating.

IMHO any machine that uses heated water (DW's and clothes washers) should have cold-water hook-up and heat their own water. I get that. No problem with that, BUT......they should also be capable of heating the water up to a range that works. "Normal" 105F in a dishwasher is a travesty. No wonder there are so many complaints of poor performance.

American built dishwashers use a timer in conjunction with an element to heat water. The timer is active long enough to heat from 105 to 120 for normal operation and from 120 to 140 for sanitary washes. If water leaves the tap at 120 degrees, temp will drop to 105 in just a matter of minutes, timer will kick in, and water will heat back up to 120 or should under normal circumstances. If your tap takes a while to get hot, the cold water infill will be considerably less than 105 and washing could be compromised because the timer kicks off before the temp is adequate for washing.

European dishwashers use a small heater and thermostat to heat water to the correct temperature. Therefore; whether the infill is 50 degrees or 120 degrees, temperature is always adequate. Also, some of these cycles wash as high as 170 degrees. Increasing temperature compensates for less water and detergent however wash times are usually longer. This design is better for the environment and helps to offset phosphate free detergents.

The heating coils/timer aspect of American dishwashers can not regulate temperature well enough to wash china or crystal.

Thermostats and a water heater can regulate the 115 degrees need to wash c/c

Worth a shot, but I'd suspect something else if you're going through valves at that rate.

high mineral content in southern california water....? who knows!

60c equals 140f. I don't keep my hot water above 120f so my hands don't get uncomfortable washing things. My Diamante is connected to the hot supply.

i'm going to run it for a while on cold just to see how things go.....if i don't feel that the dishes are getting as clean as they were on hot, i'll switch back and adjust the water temperature. my dishwasher is just so close to the water heater that i would really have to turn it down to make sure the water isn't too hot coming in.....

I've had my dw on cold water hookup for 12 years. With the onboard heater there is no need to use hot hookup. Additionally, depending on the model and the water temperature house hot water -- ideally 125F -- is too hot for certain cycles. Miele used to say cold water only then they got complaints and said either or. But cold is best bet IMO.

I use a hot/cold mixing valve on my Miele Optima to feed the unit temperate water that is probably around the crystal cycle preference temperature value (a cycle I never run because washing by hand with an RO water rinse leaves wine and beer glasses crystal clear and totally free of rinse aid residue). I expect my Miele heats the water it gets a bit for each regular turbo pot/pan whatever cycle.

The claim that feeding the unit cold water is more energy efficient (green) than feeding it hot water can only be true if the energy one uses to heat house water is more expensive per delivered BTU (has to include furnace or gas heater efficiency) than the electricity the unit would use to heat the water instead. Electricity is the more expensive approach in NH, and I suspect that is true many places in the USA.

If this were also true in Germany, then the high-end solution would be to plumb the unit for both hot and cold feeds (like even the most low-end clothes washing machine manages to do) and let the dishwasher control the temperature for the cycle without any heating at all.

I understand the confusion about why hot water is less "gentle" on crystal. If truly crystal (fused quartz), I would expect the glassware to be highly resistant to detergent effects. (I doubt that there is much fused quartz glassware available.) If borosilicate glass (like original Pyrex), or normal lime glass, then hot detergents might be fairly accused of leaching thereby causing fogging of the glass surface. My previous American style hot washing dishwasher could fog standard glassware after enough washings using then Cascade.

kas

I am currently without a water heater for a few days, so I'm going to try my Miele with non-heated water going in. Wish me luck!

Luck not necessary, it'll work just fine with cold water feed.

kaseki, using cold feed to save energy is more than just price difference between electricity and gas.

The main reason is that in most homes, there is a fair long distance between the gas water heater and the wash dishwasher. As new dishwashers draw less and less water, it is possible that the water entering the dishwasher from the hot feed is still fairly cold (btw, for this same reason, I doubt the necessary to use a mix valve, as the hot water would likely not be that hot). The tankless water heater takes even longer the heat the water to set temperature. So the dishwasher still has to heat the water more than should by electricity. A big chunk of the energy contributed by gas is wasted in heating the water between the water heater and the dishwasher, which won't reach the dishwasher at current washing stage. And by the time the dishwasher draws water in the next stage (the duration of each washing stage is fairly long in new generation of dishwashers), this heated water is already cooled down. There would be no double heating issue when using cold water feed.

Another reason is that in certain stage(s), hot water is not required by the program. So the energy contributed by gas is not necessary.

Miele suggests using hot water feed only when the water is heated by sources like solar energy in point view of energy consumption.

My dishwasher takes only 0.8 gals per fill. It takes approximately three fills to purge the supply line for some degree of heated water to reach the machine. The machine essentially runs on a cold fill if I don't run the kitchen faucet before starting.

I monitored the temp recently with a remote-sensor thermometer. Temp rise during the cycle is via water heating in the dishwasher. Residual heat of the dishware and machine partially contributes to the higher temps at the beginning of the rinses.

73°F start of prewash
76°F end of prewash

75°F start of main wash
130°F end of main wash

108°F start of rinse 1
112°F end of rinse 1

102°F start of rinse 2
129°F/130°F end of rinse 2

Your points are all generally valid. I'll have to take measurements to check my situation. However, I think it would be rare for the dishwasher to be started when the water lines had not been recently used.

My hot water line to the kitchen sink area is insulated, higher than the furnace and hot water heater, and stays pretty warm once any water has been recently used. Tubing length overall is about 30 ft, most of which is half-inch, leading to a volume of less than 0.03 gal. Hot water is nominally tempered to 139F but may be affected by lime build-up in the control.

As far as the cold water option, in the winter the cold water into the house can reach 40F, but maybe warms to 50F at the sink area. I'm not sure what that would do to overall cycle duration, but I bet I would hear some local, er, feedback, if there were any further increases over what is already perceived to be an unnaturally long cycle.