Whirlpool's revised models - what have they changed in the normal cycle?

[michaelz08]

This really has annoyed me more than it should. In some of Whirlpool's revised models, they are advertising a drastically shorter normal cycle that's only 1:30 long. When you factor in that includes a heated dry, that's a very short wash.

This is antithetical to everything I understand about how modern dishwashers and detergents work. The alternating of active zones increase wash time, and modern detergents need more time and heat... and American style exposed elements are comparatively slow to heat versus the flow-through heaters of others. So less main wash time would seemingly mean less of a chance of hitting an acceptable wash temp, meaning less heat to both break down food and less activation of the detergent's enzymes.

The only other clues: A) Water usage is up from 2 to 3 gallons, and B) The other variants of this model (Maytag, KitchenAid) have longer normal cycles with lower standard water usage (more comparable to pre-revision models, but still up to 30 minutes shorter time) and C) the Sensor wash cycle has decreased as well, but not as severely (and this always seemed to be their "non-EPA normal" type program).

Higher wash pressure was my first thought, except the motors part numbers are the same between pre and post revision models and they're single speed motors. Higher temps is out of the question since I don't believe the heater has changed.

This seems like a recipe for a bad wash? They don't publish the cycle breakdowns anymore so it's like grasping at the air trying to understand this given how little has changed mechanically. While Whirlpool has pretty decent reliability swings, I've always thought they made good performers and seem to have thought things well out as far as dishwashing principles go, so I find it hard to believe they'd just neuter performance completely for the sake of advertising.

 

[Marky_Mark]

I have wondered about this too. The first photo below is the cycle chart to one of the older Clean Water Wash models (KDTM804KPS), that is still sold on the KA website. The second chart is from a newer model (KDTS624SPS) with auto door open.

• The newer models appear to wash at a higher temp, especially if sani rinse is selected
• Drying times are longer on the newer models
• Enabling hi-temp wash or sani rinse now definitely adds extra water and time, rather than possibly adding it, as on the older models. That could mean the older models could add the extra water and time automatically based on the turbidity sensor reading, while the newer ones only add water and time if those options are chosen. Or it could mean the older ones didn’t always add it even when selected.
• Longer express wash on newer models and a shorter, thirstier normal cycle

That said, the KA website is pretty bad. Its descriptions and documentation have been inconsistent for years. So, take all of this with a grain of salt.

The older model:





The newer model:

 

[henene4]

High temp wash:
As far as I understand, there used to be a variance in pre-washes based on incoming water temp.
I think they did more pre-washes if temps were lower in the hope to purge lines and to raise the temp of the dishes further before the main wash heating started.


That plays into my general theory abou this:
As far as I understand, the current administration over the pond reduced usage requirements? Means DWs can now not only use more water, but also more energy.

Getting better cleaning in less time with the same chemistry does mean more energy and more mechanics - see Sinner's cicle.

But, the usage increase here, would indicate either an additional pre-wash or something entirely different.
The Express cycle somehow got longer - but as far as I understand, one way that is that fast is running multiple racks at once. And running multiple quick pre-rinses to get really hot water.
I would not be surprised if the new Normal cycle just adds about 1l/1qt per fill and just runs more racks at once. Add basically heating throughout, and you could get pretty decent cleaning in that time. Even if it ran the heating element continuously for 90min, in the US, that would "only" be something like 1.5kWh.
I think many of the new machines with the bigger tubs have variable speed pumps. You can just ramp those up to compensate for the increased water movement rate with multiple arms running at once.



And I mean, that's what people asked for: Faster DWs. Even if that means more usage.
As weird I find that demand (the same as dryers needing to be fast, while data shows most people leave their laundry in the dryer for over an hour after the cycle) I don't see why it couldn't be done if the usage isn't the thing stopping you.

 

[Marky_Mark]

I did have an older Clean Water Wash KA from about 2015 and I did run it on cold water once -- on that occasion it drained the prewash within about 10 seconds and refilled.

I also used the KDTM704KPS for a month and that one only ever did one prewash except on the Express cycle, which did 2 prewashes, main wash and two rinses. The Express cycle main wash was 32 minutes and heated throughout whenever the lower or middle racks were being sprayed. The Express main wash typically started at about 45 ℃ and ended at about 65 ℃. This machine had a 4-way diverter and only ever sprayed one of the four zones at a time. It never heated when the top sprayer or the 3rd rack spin tubes were active. I never tried running this machine on cold water.