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Old 06-22-2022, 08:16 PM   #15
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Also, if not yet aware. You can add more water to the bowl before flushing by using the left button on the flush switch. When using hi flow, this will almost fill your bowl with water. Water is your friend when flushing. Do not flush anything other than bodily fluids and approved toilet paper.
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Old 06-22-2022, 08:34 PM   #16
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I have a similar issue as the OP. I've always thought that the pump or macerator doesn't stay on long enough, all of the water doesn't leave the bowl before the pump stops. I am sure there is a timer built into the controls but doubt it is adjustable.

The rear toilet is my wifes and I have the half bath. She doesn't think it's a big deal so I haven't done any research on it. Oh, and the times I've tried to add more water, the pumps still stops to soon with even more water still in the bowl.
Scott and Deanna
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Old 06-24-2022, 07:25 PM   #17
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We have found water pressure to be a KEY component with getting a good flush. We also use the fresh water tank and onboard pump most of the time as it provides plenty of water pressure. We also use the autofill to keep the fresh water tank level up.
We have found that when solid waste is involved, hitting the "add water" button long enough to get a good flow of water into the bowl and then hitting the flush button immediately performs the best at cleaning the bowl and eliminating the backwash problem you are describing.
We do not have the ring and film problem.

Originally Posted by CAllingham View Post
We have a similar issue on both toilets where small bits of ground-up TP float to the surface after a flush even when set to the higher water usage setting. For us, I think it's a low water pressure issue.

We're setup on campsite water with a pressure regulator at 50psi, then filter through a Clear2O DirtGUARD 20-micron sediment pre-filter and a Clear2O 1-micron carbon block filter, then through an On The Go Double Standard water softener, into the water hose reel, and through the on-board whole house filter. Under this setup, water flow throughout the coach is noticeably lower than desired, and we get the toilet flush issue described above.

So we've taken to using auto-fill to run water into the tank at the rate our filtration/softening setup produces, then use the water pump to provide strong pressure at faucets and the toilets, which solves our flush issue.
Wil, Donna, and Daisy
2020 Newmar Dutch Star 4081 (Freightliner)
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Old 06-28-2022, 04:52 PM   #18
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Domestic macerating toilet not flushing completely.

We had a similar issue where our macerating toilets were not flushing completely. They seemed to have run out of oomph and the water never completely emptied, leaving bits of TP and other matter in the bottom of the bowl until we flushed 2 or 3 times. It turns out there is a vacuum breaker on the rear of the toilet which in our case had become clogged with dust. We removed the dust and voila, good as new. On our toilets it sits just below the rear porcelain backing on the toilet and is connected via a hose so you can angle it out to get access. Iíve attempted to attach a photo.
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Old 06-28-2022, 08:33 PM   #19
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Originally Posted by Dutch Star Don View Post
Are you saying that BOTH of your toilets don't flush well and spit back debris? If just one is doing this, you may have an issue with the macerator, possibly a blockage.
We have the same issue. Both toilets do the same thing. I will try turning on the water pump when hooked up to city water to see if the flush is improved. Thanks for the idea!

Joanne and Gary
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Old 06-28-2022, 08:36 PM   #20
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I will take a look at the vacuum breakers to see if they are clear of debris. Another great suggestion!

Joanne and Gary
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Old 06-28-2022, 09:25 PM   #21
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I tend to agree about lower pressure possibly being a thing. I have a 35psi regulator as I often stay at a resort with water but no sewer at the site - makes it easier to conserve. Iím on eco mode with the toilet and have to flush at least twice for solids. No big deal. I just wait till itís halfway up and flush. (2020 Newmar Kountry Star)
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Old 06-29-2022, 02:22 PM   #22
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We use the water save mode and fill the bowl only when needed to flush solids. This works well for us and we dump when the yellow light (3/4 full) comes on about every 4 to 5 days.
Jerry, Helga & Touka (Rescue Rat Terrier Mix)
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Old 06-29-2022, 06:33 PM   #23
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macerator toilet

I agree, the flush is not the greatest with these. First I would make sure your Anti-siphon valve is not dusty as this will impair the ability for it to pull in air to add to the water flush, increasing the relative force of the flush. We had a valve ( were told we have 2) go bad and retrospectively think one was not working from day #1. After 5 years, despite religiously cleaning, treating, making sure we were level, we developed an obstruction in our outflow from the macerator. We had to auger snake from above, and below after taking the shallow tool compartment apart and cut the 1 1/2 inch drain line, put in a cleanout valve. We developed a problem called Struvite. The industry standard is 1/8 inch slope over that distance. The drain schematic from Newmar showed 5- 90 degree turns in our line before terminating at the black tank some 12 plus feet away! The line only slopes 1/8 inch per foot per industry standard, we had about 11/4 inch slope so surprising more don't have problems.
Once you get your toilet poor flush issue remedied, I would do as we do, on a monthly basis, I put in 1 cup of white vinegar, fill with boiling hot water then flush. I believe it helps keep the drain line cleaner. By the way, since we had the 2 anti-siphon valves replaced our flush is MUCH better
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Old 06-30-2022, 10:42 AM   #24
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Mzkismet, did you replace it with the same part that comes with the coach?

Joanne and Gary
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2019 Ford F150 toad
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Old 07-05-2022, 03:42 PM   #25
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Thank you for the tips! I plan to take a look at the vacuum breakers and will certainly look at running some boiling water into the lines w/ vinegar. Hopefully I can get these thrones fit for a king!
2020 - VTDP 4037 - K2
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Old 07-05-2022, 04:33 PM   #26
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Sage Advice from Service technician

We had 2 Dometic Macerator toilets with our Newmar Mountain Aire and now with our DRV Mobile Suites. I had a problem with one of the toilets in the Newmar but as it turns a small plastic pill bag got caught on the impeller causing a lot of racket. While repairing the issue the technician told me that products you use on regular house toilets should not be used on RV toilets because the seals and gaskets arenít designed for harsh chemicals like bleach or any of the products you find in a grocery store for cleaning toilets. His advice was like another poster replied Dawn Dishwashing liquid. We buy the dawn spray bottle that foams to clean our toilets. I live in Texas and it has been 100+ most of the past many weeks. Water is tepid hot without heater so we have to clean about every other day to keep the algae at bay.
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Old 07-05-2022, 04:53 PM   #27
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My problem is high waterÖ. I have tried adjusting both Macerators but after one use they go back to about 3 or 4 inches in the bowl,think I will try Dons approach and leave the dump valve open.
2017 Dutch Star 4369 Spartan
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Old 07-06-2022, 05:49 AM   #28
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We donít store with any water in the tank and I flush the toilet so no water remains in the bowl. Iím sorry I canít help with the other partsÖ.good luck
Melanie and Brian Elo
Mooresville Indiana
2020 Newmar Dutchstar 4054 DP- Spartan K2 Chassis; tag axel
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dometic, toilet, macerator

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