Miele G7166 - Is this Cavitation?

[michaelz08]

This has been bothering me for a bit, but has become more on my mind as I'm using the pots and pans cycle more often now. The sound I'm referring to is a loud 'shhhhhh' that occurs at regular intervals. It sounds more subtle in the recording but to really manages to be not only very audible in person, but pretty annoying. The Pots and Pans cycle is loud enough as is, and this is making me not want to use the cycle altogether.

I can hear the arm's spinning slow as the sound occurs, and it occurs primarily when the bottom arm is in operation. It only occurs on the higher-pressure wash cycles such as Pots and Pans, QuickIntense, and SaniWash. It never does this on lower-pressure cycles such as Normal, even with ExtraClean enabled.

I tried adding water, and did perhaps 12 ounces (but not more out of concern for overfilling it, the base is very shallow), and it seemed to perhaps make a slight difference... But I could not tell definitively.

Audio attached, recorded with the phone near the bottom of the unit. Thoughts are appreciated.

Extra info: Cascade powder detergent inside the auto-dos cartridge, so it's determining how much detergent to use. I don't recall seeing excessive suds when I opened the door to add water.

 

[vacerator]

Either not enough water in the tub, or a loose item blocking a spray arm intermittently.

 

[michaelz08]

Either not enough water in the tub, or a loose item blocking a spray arm intermittently.

I can confirm no items blocking the arm, it occurs reliably on all high pressure cycles.

How could there be not enough water? It meters it's own filling and I leveled it myself.

 

[Marky_Mark]

This sound is most likely to happen when the pump is circulating at its highest rate, which is when it's operating the lower wash arm on cycles such as pots & pans and QuickIntenseWash.

My first thought is that it's due to suds. I've often heard this (much worse) when using Cascade Platinum pacs in various dishwashers including Miele. But I've never heard it when using Cascade powder though. It could also be due to a slight lack of water.

Next time it does this, if it happens during the main wash, open the door and add a quarter cup of vegetable oil and then let it continue spraying for a few minutes and see if it goes away once the oil has mixed in, which would kill any suds. Even though you didn't see suds, the pump could still be cavitating.

Also, try adding a litre of water and see if that stops it. Adding that much water won't overfill it.

At what point in the cycle does this tend to happen?

Mark

 

[neptuneguy27]

Definitely cavitation. My Miele 7106 does this not only in the higher pressure cycles but also when I've really packed it full. However, in the latter instance the dishwasher will top off the water level until it is running at a constant pressure. In my experience Cascade pacs are the worst offenders for suds and cause that noise in any cycle. I've not tried Cascade powder yet in the Miele, but never had a sudsing problem when Finish powder was available nor with Walmarts Great Value powder, which I am currently using.

But I digress, my machine does this same thing in the Pots & Pans, QuickIntense, & Sani Wash cycles or when I have the Intensive Lower basket option selected in the Normal cycle. But it only seems to be an issue during the pre-rinse and first part of the main wash; after that it seems to settle down a bit. Or I have become deaf to it and just don't notice the noise as much.

Chris

 

[Marky_Mark]

The sudsing cavitation often goes away once the water has reached a higher temperature -- it's much worse at lower temps. If a good amount of food soil is present, especially fatty/greasy residues, that will stop it from happening.

Despite the sudsing and cavitation, I've found Platinum pacs to be one of the best detergents. But the noise is irritating!

 

[michaelz08]

Thanks for the input. I’ll try the water and then the oil in subsequent washes. I’ll be running it tomorrow and I’ll select the cycle just to try.

I have the water softener enabled and set to around my water hardness, when it was set for exactly the hardness I had issues with it being too sensitive to the amount of detergent used (it wouldn’t suds, but would leave residue in glasses if I put even a teaspoon too much).

It persists through the entire main wash, and in my open living area it’s really unpleasant. Especially when you have the notion that it may be something that it’s not supposed to be doing. Listening to it for so long is maddening. It never adds any extra water to compensate.

Load size does not matter either, I wouldn’t say there’s extra dishes or grease in these loads, just that they’ve got baked on residue that I know needs more heat/pressure.

Good to hear I’m not the only one experiencing it though. But I expected less operational fuss for the price.

 

[DADoES]

My DishDrawer added water in one of the several instances of trying Cascade Platinum pods, all of which instances caused excess sudsing. That's the only time in 20+ years I'd ever noticed it adding water after the initial fill.

 

[gelaundry4ever]

This has been bothering me for a bit, but has become more on my mind as I'm using the pots and pans cycle more often now. The sound I'm referring to is a loud 'shhhhhh' that occurs at regular intervals. It sounds more subtle in the recording but to really manages to be not only very audible in person, but pretty annoying. The Pots and Pans cycle is loud enough as is, and this is making me not want to use the cycle altogether.

I can hear the arm's spinning slow as the sound occurs, and it occurs primarily when the bottom arm is in operation. It only occurs on the higher-pressure wash cycles such as Pots and Pans, QuickIntense, and SaniWash. It never does this on lower-pressure cycles such as Normal, even with ExtraClean enabled.

I tried adding water, and did perhaps 12 ounces (but not more out of concern for overfilling it, the base is very shallow), and it seemed to perhaps make a slight difference... But I could not tell definitively.

Audio attached, recorded with the phone near the bottom of the unit. Thoughts are appreciated.

Extra info: Cascade powder detergent inside the auto-dos cartridge, so it's determining how much detergent to use. I don't recall seeing excessive suds when I opened the door to add water.

When using heavy on my LG, it does that during final rinse. I stick with auto and it doesn't happen. Try using auto.

 

[gelaundry4ever]

This sound is most likely to happen when the pump is circulating at its highest rate, which is when it's operating the lower wash arm on cycles such as pots & pans and QuickIntenseWash.

My first thought is that it's due to suds. I've often heard this (much worse) when using Cascade Platinum pacs in various dishwashers including Miele. But I've never heard it when using Cascade powder though. It could also be due to a slight lack of water.

Next time it does this, if it happens during the main wash, open the door and add a quarter cup of vegetable oil and then let it continue spraying for a few minutes and see if it goes away once the oil has mixed in, which would kill any suds. Even though you didn't see suds, the pump could still be cavitating.

Also, try adding a litre of water and see if that stops it. Adding that much water won't overfill it.

At what point in the cycle does this tend to happen?

Mark

I've had the sudsing with platinum plus by Cascade before, and that's why I switched to ultimate by Finish.

 

[gelaundry4ever]

The sudsing cavitation often goes away once the water has reached a higher temperature -- it's much worse at lower temps. If a good amount of food soil is present, especially fatty/greasy residues, that will stop it from happening.

Despite the sudsing and cavitation, I've found Platinum pacs to be one of the best detergents. But the noise is irritating!

Don't get me wrong, they do clean fine. I just don't like the cavitation.

 

[gelaundry4ever]

Thanks for the input. I’ll try the water and then the oil in subsequent washes. I’ll be running it tomorrow and I’ll select the cycle just to try.

I have the water softener enabled and set to around my water hardness, when it was set for exactly the hardness I had issues with it being too sensitive to the amount of detergent used (it wouldn’t suds, but would leave residue in glasses if I put even a teaspoon too much).

It persists through the entire main wash, and in my open living area it’s really unpleasant. Especially when you have the notion that it may be something that it’s not supposed to be doing. Listening to it for so long is maddening. It never adds any extra water to compensate.

Load size does not matter either, I wouldn’t say there’s extra dishes or grease in these loads, just that they’ve got baked on residue that I know needs more heat/pressure.

Good to hear I’m not the only one experiencing it though. But I expected less operational fuss for the price.

I wish modern dishwashers would just top off the water when foaming happens during the main wash.

 

[henene4]

That sounds like the water level is slightly low or that there are suds, but not much.
During the first few minutes of a cycle when it usually does load sensing, you do hear it cavitation with the pump almost running dry, and on my G7100 that used to coincide with the pump sounding noticeably different (running faster).

Keep in mind that if the water level drops to low during the main wash, it would trigger the pressure switch and should usually register an error.


If it still cleans like it should but the noise annoys you, the one thing you really can effectively do is to either switch detergent or lower dosage.
I think the AutoDos has a setting to reduce dosage?
The powdered detergent I currently use has a standard dose of 15ml, and I think Mieles pre-set is 20ml?
I think it also does some dosing in the pre-rinse as well.
So a to high dosage plus pre-rinse dosage could easily end up as an overdose issue.


Edit:
Just checked, the G7166 has adjustable dosage and says it adjusts dosage based on cycle and in the Auto cycle based on soiling as well by itself.

The typical PowerDisc is 400g and supposedly lasts 20 cycles.
That makes a dosage of 20g the default.
Cascade powder recommends 15-30g from my quick search - and keep in mind, that's probably with DWs with no water softener in mind while Mieles PowerDisk is probably formulated with the water softener present in Miele DWs in mind.

Given you have the issue predominantly on the higher intensity or quick cycles, you might just end up in situation caused by multiple factors coinciding.

Those cycles have higher pressure and probably dose more heavily either for quick cleaning or heavy soil.
Next you have very soft water in the DW as you are using the water softener from what I understand.
And top of that you are using a detergent that's formulated for hard water, a variety of DWs and for people probably not using any in the pre-rinse in DW that uses very low fill, has a water softener and that does dose in the pre-rinse where applicable.


The curiosity that some detergents suds more at lower temps and then calm down as water heats is something I do encounter with washers sometimes.
And as you said - it still cleans fine, so it's not cavitating terribly. Just enough to hear a change.

So I'd really just recommend to knock the dosage setting down a bit.

 

[michaelz08]

That sounds like the water level is slightly low or that there are suds, but not much.
During the first few minutes of a cycle when it usually does load sensing, you do hear it cavitation with the pump almost running dry, and on my G7100 that used to coincide with the pump sounding noticeably different (running faster).

…

I just changed the dosage amount to the “less” option and will see if that makes a difference when I run it today. Thank you for your comprehensive and well thought out remark!

 

[vacerator]

My GE also cavitates. It's getting old. Going on 16 years. Mineral deposits in the inlet hose? I've replaced the solenoid valve. Pressure at the supply line is enough.