Heater temperature sensor controls irrespective of your hot water tank temperature. If your temp is high, it's cools. If low it heats.

Thanks. Good to know. So, when I choose the temp setting (I just have 5 choices for temp), it's going to be whatever temperature the machine dictates corresponds to that selection, regardless of what temp the water is coming from the lines.

My Electrolux suggests my hot water supply should be (at minimum) set at 120F.

Yes most front loaders with internal heaters "help" hold a target temp but it takes a long time to raise the temp. (hence the very long Sanitize cycles).

Remember the on board heater only kicks in when the temp. falls below a preset preference (by the manufacture) the variance can swing 3 to 10 degrees.

So don't rely on the washer to heat it's water, set your water heater at minimum 120F (140F is preferred to prevent Legionnaires' disease).

Mine is a top-loader, but I would assume the same would apply.

My water heater does not have temps listed. We did have it on A. I bumped it up to B recently. I think the only other choice is labeled very hot and has some warning on it. So, I would assume I am over the 120 degree mark. I guess I need to let the kitchen sink run for a long time and then sit a glass under it to catch the water and put in a thermometer. Is that a method to check water temp?

Yes aa62579.

I have a digital thermometer that goes high.

Run the water into a deep enough glass to hold water and the thermometer and let it run a few minutes to heat pipes, water, glass.

Slow down the rush of water so air isn't infused with the running water (the aerator), once the temp. settles that should be how hot your water is.

Some washers with onboard water heating are time-limited in how long the wash period is held/extended while the heater operates. The intended target temp for some cycles may not be reached if the initial fill is not hot enough per the machine's engineered/design parameters.

Designated Sanitary cycles typically have longer hold times but still may fall a little short of the target.

I used a 2006 Whirlpool Duet HT for a couple months. The Whitest Whites cycle and Heavy cycle (on both warm and hot temp settings) utilized the heater but only on the highest soil level. I ran a few loads on both warm and hot with cold and warm-er and hot-ish fills to test the effect of heating, and found that the end-result wash temp fell further short of the expected "warm" or "hot" target with cooler initial fills. The Sanitary cycle had a much longer heating period and seemed to always reach the target if the initial fill was at least warm.

There really isn't too much documentation about the heater. It mentions having one as a feature.

And in the manual it says - TEMPERATURE -- Wash temperature senses and maintains uniform water
temperatures by regulating incoming hot and cold water.

I only see mention of the heater in the steam cycle/option descriptions. Deep Clean w/Steam
uses a heater within the washer to maintain the selected
temperature setting throughout the wash period. (This one can be added to all the cycles - well, maybe not the cold water one, but you get the idea.)

Well, great, now I am wondering if the heater activates at all unless the Deep Clean w/Steam option is selected.

On the LG, you must select the steam option to activate the heater in any cycle where it operates other than sanitary cycle. On sanitary, the heater is automatically activated. But, as noted, that cycle is 2.5 hours long.

Okay, so I guess that is probably what it is in my Maytag as well.

Unless the Deep Clean w/steam option is added to a cycle or the Sanitize w/ steam & oxy cycle is chosen (or the clean wash cycle), then the heater does not come on and it does indeed matter what temp my water heater is heating the water up to.

Yes, unless you activate the Deep Clean button, the heater most likely won't come on to maintain the fill water temp. The Sani cycle probably needs the 120F inlet temp for the sanitization effect to take place, as the oxy won't sanitize in too cool water.

120F inlet temp is probably not that important on other cycles, as many of today's washers seem to abandon the use of hot water altogether. Consumer Reports just lowered the "warm" temp to 75F for their tests because it better reflects how many washers operate these days.

A Kill-a-Watt meter can be used to confirm when the heater is operating, wattage draw will be much higher.

http://www.p3international.com/products/p4400.html

I only had a meat thermometer. Water at the sink read 120 degrees. I wonder what it was at before bumping it up.