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F&P dishwasher leaving white scum--ideas?

Posted by fori (My Page) on
Mon, Jun 21, 10 at 21:04

My ~3 year old F&P DW double has been leaving white slinky scum on dishes lately and I can't figure out why. It wipes off and isn't in the water (unless something is precipitating out in the wash cycle). I've switched detergents in case I had a bad batch. Not that. I only fill the detergent cups about half full. I've tried heavy cycles and light ones. Top drawer and bottom drawer. We're on boring city water that hasn't given us any problems before. No softener.

Could it be a drain issue? The machine has been physically moved a bit lately (bad bad plumbers). (Really bad.) Could it be a water intake issue so things aren't being rinsed? Do I need a new one (after what those bad plumbers did to it cosmetically might not be a bad idea grrr...)?

If you can point me in the right direction, I'd appreciate it!


Follow-Up Postings:

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RE: F&P dishwasher leaving white scum--ideas?

Could be a situation of detergents going to phosphate-free formulas. Check the package ingredients. Even if you use the same brand as before the problem started, the formulas have changed. Some people run into poor performance when that happens, some don't notice any difference ... may depend on the local water conditions and such.

There may be a couple detergent brands that still have phosphates, and check your various stores for any "old stock" detergent that still have it. I've heard Walgreens may be a source since not many people tend to buy dishwasher detergent there.

As an alternative, you can look for LemiShine (citric acid) at the store with the dishwasher detergents. Use regular detergent for the prewash and LemiShine for the main wash, or detergent for both but add some LemiShine in with the main wash dose.

Or, you can buy bulk STPP (Sodium TriPolyPhosphate) and add a 1/2 teaspoon or so with your normal detergent. There has been a lot of discussion about using STPP with laundry, but it also solves the phosphate issue with dishwasher detergent. You can get it at www.chemistrystore.com. It's not cheap, but a little goes a long way.


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RE: F&P dishwasher leaving white scum--ideas?

Thanks!

I checked my detergent. No phosphates, but one I've used often is Trader Joe's store brand and it probably never had any since they're kinda crunchy granola. Also I'm in CA and if it's being phased out odds are good it was already done here, but I'm just guessing that. :)


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RE: F&P dishwasher leaving white scum--ideas?

I'm in CA too. I use Cascade powder in mine with no problem. Silly question - is anything stuck in the filters inside the dishwasher? I had that happen and that's when I found out I had to clean those things!


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RE: F&P dishwasher leaving white scum--ideas?

The pump filter cup and the large circular stainless steel main filter screen do need to be cleaned occasionally. The spray jets in the wash arm can also be clogged by debris. Definitely have a look at all that.

You might also try cleaning the unit by running a Normal non-Eco cycle (or Heavy non-Eco for slightly higher water temperature) with both detergent cups full of LemiShine.


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RE: F&P dishwasher leaving white scum--ideas?

Thanks for all the help trouble shooting. I think I've figured it out and it's a little embarrassing but I'll share...you know how sometimes when you go on vacation you turn down the water heater? It just so happens that the person who turns it down here isn't the same person as the one who notices there isn't enough hot water (and doesn't know how high to reset it).

Anyway I think the water's been too cold to dissolve the detergent. Argh?


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RE: F&P dishwasher leaving white scum--ideas?

Fori, that's not likely to be the problem. DishDrawers can work on a cold water connection. The main wash and final rinse are *always* heated to specific temperatures, per the selected cycle (the target temps should be listed in your instruction manual). Cycle time is extended as necessary to reach the temps. The only way your water heater setting may come into play is if you're only using the lowest-temp cycles (Fast or Fast-Eco) and your incoming hot water is normally already higher than the target temperature.


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RE: F&P dishwasher leaving white scum--ideas?

So the machine is capable of heating water as cold as 105 F to ~145 F? I guess it should be able to do so.

The individual drawers both started getting cruddy at the same time and they don't get the same amount of use. So I'm fairly sure it's not something like the spray arm or filters because that would only affect one drawer. (I did do a thorough cleaning of one drawer when the problem first presented before I noticed both drawers were bad.)

Anyway I've got to remove all the old scum off the dishes (it's not sticking to the dishwasher of course) before doing a proper test.


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RE: F&P dishwasher leaving white scum--ideas?

If you have hard water, you might be seeing a lime build-up. This happened to me. I was told to run the DW empty on the hottest cycle. After the cycle has been running a few minutes, open the door and add about a cup of vinegar into the water. The DW installer recommended we do this about once a month. It helps the pump function too.


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RE: F&P dishwasher leaving white scum--ideas?

Doesn't matter what is the incoming water temperature, the target temps will always be reached ... unless the heater plate is gone bad in which case the drawer should throw a fault code.

I have a tankless water heater that I normally keep set at 104F or sometimes a little less. Due to the distance from the water heater to DD and the low-volume (0.8 gals) fill, the first few fills are tap-cold unless I run the kitchen faucet first to purge the line. I've checked my DD with a thermometer. Starting with 50F incoming water, it still reached the target temps.

I'm still leaning toward the non-phosphate detergent issue being your culprit.


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RE: F&P dishwasher leaving white scum--ideas?

Good suggestion, Fun2cook! That's my bathroom, but not my dishes! :) We don't have really hard water and it takes a lot of neglect to build up deposits. This scum feels like talc. You can't rinse it off but you can wipe it off.

I got on my Google machine and one of my detergents was apparently covered by Consumer Reports back in '05 in a review of phosphate free products, so I'm not suddenly off phosphates. Buuuut...it's possible my municipal water supply has been changed. Guess I'll ask the neighbors.

I couldn't just have a kink in the water supply line could I?


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RE: F&P dishwasher leaving white scum--ideas?

I wasn't seeing any lime build-up inside my DW. But something was leaving a lime deposit on my glassware. Only Bam lime remover would take it off. Simply rewashing the glass by hand wouldn't remove the film But it wasn't like the lime build-up you can find around a faucet. Sounds like your problem may be something different, But it's a simply fix to try and see if it helps. It's very frustrating to wash dishes, and have them come out worse than they went in. Good luck.


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RE: F&P dishwasher leaving white scum--ideas?

An obstruction on the water supply line is possible but not likely. DDs sense the fill level via the prime and load on the pump rotor and should throw a fault code if there's a problem. Spray force would be reduced if the pump impeller is damaged such as a broken fin. The spray arm can also split where the halves are heat-sealed together, causing spray out the edge instead of full pressure up through the nozzles ... but that may (usually) cause leaking due to water spraying directly into the air vent at the rear.


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RE: F&P dishwasher leaving white scum--ideas?

Hrmmmmmmmm

I'm able to get the scuz off by handwashing. It's definitely not lime and it's mostly on plastic and big things that don't rinse as well.

And things are coming out much better since cranking up the house water heater. Does that mean the DD isn't heating water? Is there a single heater for both drawers or are there two?

The neighbors aren't having problems and think I'm weird. :)


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RE: F&P dishwasher leaving white scum--ideas?

Each drawer has a heating element. You can easily see it. Remove the rack, wash arm, drain filter, and the large stainless steel filter. The heating element is the circular ceramic disk that surrounds the pump impeller. If the heater is bad, the machine will throw a fault code and/or cycle progress will get stuck for a very long time in the main wash and/or final rinse when it's unable to reach the target temperature.

You didn't say which cycle you normally use or which model is your DD (603 or 605). Depending on which model and revision is involved, Fast may be low as 115F and Fast Eco 105F. Household water temp has more of an effect in that case if it's already higher than the machine's target temp.

If you have the standard model with LCD, I can tell you how to get a display of the internal water temperature while a cycle runs. The integrated model without LCD doesn't have the temperature diagnostic.

I've gotten a milky-white residue on plastics a few times, such as on these dark blue lids. Seemed to happen when the detergent dose was a little skimpy, and for sure when the detergent I use (WM GreatValue) went phosphate-free. It *hasn't* happened any more since I've been adding STPP and using no less than 4 teaspoons detergent for the main wash.


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RE: F&P dishwasher leaving white scum--ideas?

I'm going to agree with the school of thought that it's the phosphates missing in the detergent. In 2010, 16 states banned the use of phosphates in consumer detergent. Miraculously though, it's still allowed in industrial / commercial (read restaurant) grade detergent. Might want to try stocking up from on detergent from a restaurant supply store.


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RE: F&P dishwasher leaving white scum--ideas?

The C******ry Store sent us a Made in China Industrial grade in the equivalent of a flour sack (have pictures) they advertise as USA Tech grade, which means the lowest grade of purity and not recommended for use on people, though their sight is mostly soap supplies. John at TCS said they repackage what I got to pails, which is also how it was advertised, so, I was expecting a pail, too. So, not only do they misadvertise, they product is not stored in an airtight manner from manufacture point. It is the dirtier grade, and, being from China, I have little assurance it is actually STPP and only STPP. I am concerned it could contain something you wouldn't put on your skin or in your dishes. My pails come in not marked with country of origin.


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