Water heater temp's, what's the ideal Min – Max?

[beekeyknee]

Well, I was reading the service manual for the machine and it said that wash times are longer for cooler water and wash times can vary from unit to unit. Since my w/h is so close to my kitchen, maybe I shouldn't flush the water from the faucet to bring hot water to the machine. It might run longer then and work better. At my Mom's we run the water, but as I said, the w/h is at the other end of the house. Could this be right?

 

[beekeyknee]

Ralph,

It says the machine heats the first fill to 150 degrees with 1400 watts and succeeding pre-washe and main washes are heated with 700 watts while the pump is running. That's the dual Calrod working, I suppose. I'm guessing that the water entering is to hot and causing the machine to run short washes? Maybe I should turn down the w/h? It does pause and heat the first fill to condition the tank and dishes, but it sure doesn't take very long. My Mom's heats much longer. Could this be the problem? Where's stevet when you need him? I need your expert advise. Or someone else? John, maybe, if you're home yet.

B.

 

[rp2813]

Brian, I think you may be on the right track, but KA experts will know better than I would.

 

You may want to start a separate thread on this that will get the attention of Steve T.

 

[gusherb]

We have a 24 year old Ruud gas water heater with a thermostat that is not so accurate anymore, I try to keep the temp around 130, this past winter I got it to about 150 because it runs out too fast otherwise, due to our incoming water being 40 degrees and I like long hot showers.
I plan to get it replaced with a 75 gallon Rheem by the end of this year, next year new DOE regulations will basically force standing pilot natural draft WH's out of existence (I love the reliability and fact that they work without power)

 

[revvinkevin]

 

 

Thank you for all the info everyone!   I turned it down a little today and will check the temp again in a couple days.

 

Kevin

 

[chachp]

Wash times KDS 20

 

Brian,

 

My daily driver is a KDS20 and it does not circulate water while heating.  It just sits and heats the water.  The variable times in the two machines you mentioned is likely due to the water temperature entering the machine but I didn't think the water temps adjust the actual time the machine circulates water so once the water hits the right temp I would think that evens the playing field between the two machines.

 

If you are only having performance issues on the top rack only have you looked at the underside of the rubber tube that carries water to the upper wash arm?  I had a similar issue in mine and it turns out the underside of mine had a huge gash in it and the upper wash arm wasn't getting the water pressure it should.  As soon as I replaced that tube my top rack cleaning issue went away.

 

I'm referring to #14 on the attached.  From what I understand it is common for these to fail and I have seen this part still available on places like Repairclinic.com.  In my case I had an extra rack with a good one so I just swapped them.

 

[magic_clean]

Just an

observation Brian..........in picture # 6, it appears the lower wash arm is not fully seated on the shaft of the wash arm support. The stainless steel shaft should be flush with the top of the bronze wash arm bearing. This will negatively impact washability.

...L.P.

 

[combo52]

Ideal Water Temperature

120F should be fine if your DW properly boosts at least the main wash and the final rinse, I would never go past 130F for the sake of the WHs life and the life of all the hot water plumbing inlet valves hoses etc in your home [ to say nothing about a huge waste of gas or electricity of heating water any hotter than that ].

KA KDS-20 DWs do not do a good job of heating water, the only way you get any real heating is to run the Soak N Scrub cycle + the sani-rinse option, so you really have to keep your incoming water temperature near 140F. I have the KDSS-20 and keep my WH at 130F and the KD does ok but no where as good as my 1987 WP when I use the Hi-Temp Wash option.

The problem with Hobart designed and built KA DWs is none of them ever had a thermal hold in either the main wash or final rinse so not only do you have to keep the incoming water temperature pretty high and even so the wash cycles were often too short to clean really dried on food soil off dishes.

John L.

 

[jeffg]

John, the problem is that a certain amount of heat loss occurs between the tank and whatever appliance it's servicing. At least from years of advice from Launderess and others here, the traditional wisdom is that 140F is required to kill most nasties, anything less and some kind of bleaching agent (chlorine, oxygen etc) is required to do the job. But to actually get a washer full of 140F water, especially in front-loading machines where very little water is used in the first place, normally requires at least 150-160F water in the tank.

If any or all of the above is incorrect, I'm open minded and would appreciate an explanation of why it's wrong.

 

[washer111]

@jeffg

Your comments were supported by G.E. in the 80's with their literature for dishwashers. 

 

I don't have any material I can post right now, but if you searched manuals for the GSD1200 or 2800 series, you'd find they suggest something along these lines (This is not word-for-word):

Start the machine on a normal cycle. Allow the machine to complete one rinse phase, and refill for a second time. Then, stop the machine and place a candy or meat thermometer towards the centre of the tub. If the water is not 120ºF, then you must set your water heater hotter.

Later on, they simply suggested running the tap hot, filling a glass, and taking a measurement. The former was more accurate - since you actually had some approximation of water was REALLY entering the machine.*

 

*If the machine was taking several fills to get "Strong-Hot" water on-tap, then setting the heater higher may not deliver hot water faster, but means when it eventually gets there, it can cause a larger temperature rise than the cooler water might. 

 

I.e. Just because the water is 120º when it enters the dishwasher does not mean the tub temperature will be 120º. It will take several fills for this temperature to be reached. I have witnessed this with the DishDrawer: First fill with 120º water, gets me to about 86-90º, depending on room temperature. Second fill is about 95º. Based on that alone, it would take 3-4 fills to get anywhere near 120º. 

During the rinses, it stays at about 120º, and maybe drops a little, depending on the cycle and length of each rinse (Typically 3-10 minutes). {These readings were taken with the machine's on-board diagnostic sensor. It can display the temperature, in ºC when the machine is operating. Therefore, I expect the readings are reasonably accurate}

 

[jeffg]

As far as we've ever read, 140F is and has always been considered the minimum temp for sanitary washing in industry/commercial standards, in absence of bleach. Again if this is bad info I'm hoping someone will correct it.

 

[launderess]

140F

While doing a better job of sanitation than say 120F for automatic dishwashing historically the two main purposes of using temps of at least 140F were at least two.

One, to ensure powdered automatic dishwasher detergents fully dissolved. The second is that soils, fats, and oils commonly found on dishware are not easily shifted, kept suspended and or dissolved in cooler water.

Anyone who has washed a sink full of dishes using warm or *gasp* cool water will notice greasy scum forming in the water and or clinging to surfaces. Way around this is to add more product but that will get you but so far.

Older dishwashers required 140F minimum incoming hot water temps also because only a few had temperature hold features. That is the timer would not advance until the proper water temp in the wash and or rinse was reached. Standard for years was that the heater simply came on during the cycle and went off at the end or after the assigned heating period was over. Well it takes about one minute to raise water inside the DW about one degree. With the short cycles of older dishwashers starting at say 120F after about five or six minutes of heating you only ended up with 130F (if that) water temps.

Of course today modern enzyme dishwasher detergents have replaced the highly caustic stuff of old. Enzymes can be designed to work in 120F or even lower temps, but will require longer contact times to "eat" off the gunk that formerly was blasted off with scalding water containing caustic chemicals.

In order for a DW to shorten cycles it must have some sort of temperature feedback via thermometer to tell the machine water has reached the desired temp. Without such measuring ability don't see how the machine could "tell" what was going on inside the tub. As previously stated many early dishwashers fired up the heater regardless of what the water temp was and kept it on for whatever was set via the timer. A quick check of the electrical schematic should tell the tale.

 

[launderess]

Oh another thing about sanitizing dishes

IIRC NSA standards require water temps of 160F or above held for a certain period of time to avoid the use of chemicals when it comes to automatic dishwashing for ware that serves the public. Usually this is a final rinse of 180F which also serves to assist with flash drying of dishes. Everyone else has to use chlorine or some other chemical certified to do the job.

Historically automatic dishwashing detergents were loaded with chlorine based bleaching agents that worked to sanitize dishware. That plus hot to scaling water in very powerful streams that blasted grime off dishes did a remarkable job of ridding dishes of germs. Much of the sanitation was due to scrubbing off the biofilm on dishes that germs clung to and fed. So even if the germs were alive they still were flushed down the drain.

Modern enzyme automatic dishwasher detergents cannot contain chlorine bleach but do have sodium percarbonate (oxygen bleach) along with often an activator. This forms peracetic (sp?) acid in water which is a powerful disinfectant. Indeed the liquid version is what brewers use to sanitize beer bottles before they are filled.

 

[beekeyknee]

Thanks everyone for your suggestions. As Ralph suggested, I started a new thread in the Imperial forum as dishwasher problems don't directly fall under the heading of w/h temp. settings. The links is below and I will respond to your replies. Thank you.

B.

KDS-60 Wash Cycles Too Short

My new to me KDS-60 wash cycles are too short and the pause to heat the water is also very short. My w/h is very close to my kitchen and is set on the highest setting. The incoming water temp. is 130 and that's before the burner kicks on. I just checked it after the burner has been on. It goes...

www.automaticwasher.org

 

[jeffg]

Launderess, great info. Thanks.

Among the NSF's tests for clothes washers are one for sanitation performance (P172) and another for allergy reduction (P351). The sanitation test requires a 99.9% kill rate for germs and a water temp of 140F, while the allergy reduction protocol is less stringent (kill rate is 95%) and requires 131F, the temperature at which dust mite allergens are fully removed (see bottom link, also these two):

http://www.thefreelibrary.com/NSF+I...ol+for+Clothes+Washers+to+Help...-a0216692155

http://www.healthyhouseinstitute.com/a-764-NSF-Certifies-Sanitizing-Ability-of--Washing-Machines

http://www.nsf.org/newsroom_pdf/HP_P351_QA_Bifold_LT_EN_LHP29060112.pdf