Community Forums

haveaday · 06-07-2023, 10:37 AM

Hello,

On our 2017 DSDP 4310, both Dometic macerating toilets require at least two flushes to end up with a clear bowl. With one flush, the bowl is initially clear but a ground up slurry comes back up. It's usually mostly ground up (RV safe) toilet paper.

Is there a duck-bill, joker or some other one-way valve that needs replacement?

Thanks!
Ben

Dutchstar411 · 06-07-2023, 12:22 PM

Both of mine, whether HIgh Water Level setting or Low Water Level Setting seems to do, for the most part, exactly what yours does. So I'll keep watching this thread to see if its normal, or is someone changed out a part, duckbill or motor with improper angled fins to correct this.

UMXHAULER · 06-07-2023, 01:44 PM

I have seen this on the low water usage setting but never an issue on the high usage setting.

Old-Biscuit · 06-07-2023, 01:52 PM

What MODEL is this Macerating Toilet????

Are you using High Water Level Setting??

Capt. Bill · 06-07-2023, 02:57 PM

I've never had an issue like yours, but I keep mine on the High water setting.

Happy Trails

haveaday · 06-07-2023, 03:09 PM

The toilets are Dometic 8700 series models. I currently have them in low water mode but I've observed problems in both modes. As long as I'm going to have to flush twice, I certainly don't want to use 0.85 gallons for each flush or a total of 1.7 gallons of water. That will fill the tanks faster than these toilets already do.

-Ben

Old-Biscuit · 06-07-2023, 03:21 PM

Sounds like you need to remove discharge pipe and check for obstructions
*Maybe inside pump also
(No duck bills on the model)

Pump should suck up contents of bowl, grind into slurry and discharge it up and out of discharge pipe loop
Clean water should refill bowl ,,,,, slurry coming back in either pump is failing or pump/pipe are obstructed

https://www.environmentalmarine.com/...h-panel-parts/

Dutch Star Don · 06-07-2023, 05:46 PM

This has been discussed before. One of the fixes is cleaning the vacuum breaker on the back of the toilet. It's right at the top attached to a black tube. Clean the filter off. See post #18 in this link.

https://www.irv2.com/forums/f103/dom...-584573-2.html

On a side note, the newer models, I think 2022 and 2023, they ran out of the Dometic switches (Covid shortages) used on these toilets. They came up with a replacement that has one button you have to push to flush and a second button for water fill. Not a lot of Happy Campers with those new switches. Apparently, Newmar now as the original style back in stock.

Ricci · 06-07-2023, 05:55 PM

Hi - It is possible that the slope from the macerator to the black tank has an uphill slope at some point. That will cause dirty water to lay in the pipe and backfeed somewhat. Also try some Dawn in the toilet for a few flushes as there is a lot of oil content in waste that can build up on parts and hoses. The Dawn may break some of that up.

Tom

Old-Biscuit · 06-07-2023, 08:25 PM

Clarification on components

Anti-siphon valve....part of discharge pipe, located at top on discharge side of loop (item 10)
*it Closes when flushing then after flush it gets pulled open and breaks any siphoning action

Vacuum Breaker....located at top of water line to bowl (Item 4)
*it Closes when flushing then after flush it gets pulled open and allows some CLEAN water to go into bowl

Slurry coming back in after flush is coming from pump/discharge because it is NOT being completely evacuated by the pump

Need to look into pump operation/discharge line obstructions

Suburbazine · 06-08-2023, 04:02 PM

I've found the solution to mine getting backflush was to increase the water pressure on the plumbing. I keep it at 60psi and 40psi open pressure, this gets sufficient water introduced to the bowl to actually flush the macerator clean.

Basically, you have to have clean water running through the macerator to prevent backflush.

Dutchstar411 · 06-11-2023, 02:01 PM

Quote:

Originally Posted by Dutch Star Don

This has been discussed before. One of the fixes is cleaning the vacuum breaker on the back of the toilet. It's right at the top attached to a black tube. Clean the filter off. See post #18 in this link.

https://www.irv2.com/forums/f103/dom...-584573-2.html

On a side note, the newer models, I think 2022 and 2023, they ran out of the Dometic switches (Covid shortages) used on these toilets. They came up with a replacement that has one button you have to push to flush and a second button for water fill. Not a lot of Happy Campers with those new switches. Apparently, Newmar now as the original style back in stock.

Thanks, Don, for the heads-up on this. Cleaned both of mine today and tested with TP on low and high water levels, (no other "matter"

), and both seemed to work with 1 flush. Next trip is a month away, so keeping fingers crossed.

MarkMaxPayne · 06-19-2023, 12:17 PM

Quote:

Originally Posted by Dutch Star Don

On a side note, the newer models, I think 2022 and 2023, they ran out of the Dometic switches (Covid shortages) used on these toilets. They came up with a replacement that has one button you have to push to flush and a second button for water fill. Not a lot of Happy Campers with those new switches. Apparently, Newmar now as the original style back in stock.

Service manager at Bish's in Junction City told me that this "swapped switch" due to "covid supply chain issues" was the issue with my new 2023 New Aire and that he had ordered the correct switch to resolve now that they are available again (says there is a resistor added to the switch such that when you press flush that it also triggers the water fill at the same time vs trying to flush with no water being added). I have a service appointment scheduled for that, adding spartan tow vehicle TPMS sensors (requires their programming gun), and a couple of other "new rig" issues the first week of July. Can let folks know if it resolves the issue or not once installed.

Best,
-Mark

Dutch Star Don · 06-20-2023, 10:26 AM

Quote:

Originally Posted by MarkMaxPayne

Service manager at Bish's in Junction City told me that this "swapped switch" due to "covid supply chain issues" was the issue with my new 2023 New Aire and that he had ordered the correct switch to resolve now that they are available again (says there is a resistor added to the switch such that when you press flush that it also triggers the water fill at the same time vs trying to flush with no water being added). I have a service appointment scheduled for that, adding spartan tow vehicle TPMS sensors (requires their programming gun), and a couple of other "new rig" issues the first week of July. Can let folks know if it resolves the issue or not once installed.

Best,
-Mark

I posted this a while back, but it only applies to the 2023 coaches. Newmar ran out, or I should say Dometic ran out of the original switches, so they came up with this version and it has been problematic. Our friends have a 2023 and they complained to Newmar. Apparently, Newmar now has the original switches back in stock and will send them to you.