Dishwasher hot water usage

When a dishwasher uses hot water from a hot water pipe, does it know it should wait till the hot water runs hot, or does it just go ahead and get whatever comes out of the pipe?

If a dishwasher has the capability of heating its own water, would it make sense to connect it to the cold water? If it gets cold water from the hot water pipe, then, by the time it finishes getting the water it wants, the hot water pipe would start to get hot, which would be wasted while waiting for the dishwasher to use it again. That problem would be solved by connecting it to cold instead of hot, so no hot would ever be wasted. Right?

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Reply to
Don & Lucille

Reply to
Mike

Just use it as directed in the instructions, in other words, don't worry.

It will or will not heat water as it is designed. They are all designed to connect to the usual domestic hot water and expect that there will be some cold water come in first. Don't worry. I believe almost all of them today have their own heater to increase the temperature above the usual domestic hot water temperature. Of course no matter if the water is heated before it gets to the machine or after, you are going to pay for heating it either way. If you have an electric water heater it will be the exact same price if you have a cheaper source for your domestic hot water it will cost just a little more, but not enough to justify increasing the domestic temperature setting.

Reply to
jmeehan

To clarify, the dishwasher in question is presently always set to use the cycle that heats the water, because the water is never reliably hot. Even if we run the water to get it hot, it doesn't stay hot very long, because the pipe is not insulated, and goes under the slab foundation.

Ideally, we should set it up with some kind of switch to be able to switch back and forth between hot and cold water, so we can experiment with different cycles etc., to see which get the dishes cleanest, and which result in higher energy bills. Also, this dishwasher can take hours. But even if we put it on its shortest, non-heating cycle, it still seems to take hours. Or at least a long time.

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I agree just dont think about it, mine heats the HW until its at a certain temperature, some dont, messing with cold-hot is a waste of time. You want to save money, do it by hand.

Reply to
ransley

No. Leave it connected to the hot water. Go read a book or remove your spouse's clothing. Either of these is a much better way to expend time & energy.

Reply to
JoeSpareBedroom

dishwashers only heat water if put in the sanitize setting.

Incoming water should be 140 or more degrees and be close to the source.

s
Reply to
Steve Barker DLT

My dishwasher is hooked up to the hot water line only. Our gas water heater is set to 125 degrees, so the dishwasher heats it to higher temperatures. Cold water washing seems to be the trend, but I'm not convinced cold water kills pathogens as good as hot water. My washer does not have a "sanitize" setting--I thought it sanitized at whatever settings.

Reply to
Phisherman

If sanitization was truly the goal, the water would be at 212 degrees fahrenheit. According to our local health department, the combination of friction (from the water) and soap is enough to remove germs. Hot water will do a better job of loosening food that may've dried onto the dishes while they were waiting to be washed, though.

Reply to
JoeSpareBedroom

You're right. Before hot water, when eating and cooking utensils were washed (if washed at all) in cold water, pathogens multiplied and the human race died off.

Home hot water cannot kill most bacteria and viruses.

I'll bet you don't even eat food that falls on the floor!

Reply to
HeyBub

And some believe you need your water heater at 120 to kill the pathogens,so I guess we are all going to die if we drink water from city storage tanks

Reply to
ransley

If you feed it cold water, it will take longer to heat the water, slowing the cycle. Run the water before you start it till the water is hot to speed the wash. If you heat water with cheaper fuel (Gas), it will cost less to use the hot water supply. Dishwashers may not need to heat the water after the first cycle, as one hot cycle should wash and sanitise, and rinsing doesn't need the highest heat.

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Bob F

Anagram wrote in news:GeHmk.3045$ snipped-for-privacy@fe085.usenetserver.com:

If you give me the full model number I MAY be able to get you the timing diagram. It has every piece of info that happens at each different cycle.

BTW, it is often tucked behind the kickplate during install for any future the service techs.

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Red Green

"HeyBub" wrote in news:Q6adnUUua8ww_wbVnZ2dnUVZ snipped-for-privacy@earthlink.com:

That must mean I'm a cockroach. They survive everything man and Mother Earth has been able to conjure up for millions of years.

Reply to
Red Green

It takes what comes out. Most instructions tell you to run the hot water in the sink until the cool water is flushed and it runs hot.

No It is designed to boost the water temperature on one or two cyles, not the entire process. You need hot water for hte best cleaning job.

If it gets cold water from the hot

Wrong

Reply to
Edwin Pawlowski

Takes a big, uh, roach, to admit that.

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J. Clarke

Red Green wrote in news:Xns9AF3D40A985CDRedGreen@216.168.3.70:

Maytag "Jetclean Dishwasher Quiet Plus" model number MDB6100AWB.

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"Bob F" wrote in news:0vqdnTqVM_t1FAbVnZ2dnUVZ snipped-for-privacy@comcast.com:

It seems to have several phases. A preliminary wash that disposes of garbage by sending it to the in-sink erator. Other phases after that.

Here is what I think might be happening in the phases after the first: The water in the pipe is no longer hot at the start of the phase. The dishwasher draws that cooled water from the pipe. The house water heater replaces that water in the pipe with hot water. The dishwasher proceeds with that phase, starting by heating the cooled water, while the hot water in the pipe cools. So the hot water in the pipe would waste its heat while at the same time the dishwasher would be wasting energy to reheat water whose heat was already wasted.

Electricity around here is almost as cheap as natural gas. Some months it might actually be cheaper.

Those are the reasons why I think it might be a good idea to try switching the dishwasher to use cold water.

It's true that it would take hours. But it takes hours anyway. An extra hour isn't likely to be a big deal. You would want to run it while you sleep or while you're not home or whatever.

Regardless, it does a good job of getting the dishes clean.

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ransley wrote in news: snipped-for-privacy@m36g2000hse.googlegroups.com:

The pathogens probably thrive in a range of temperatures, such as between

80F and 105F, or some such range. The city water supply is probably below that range.
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