Dometic Macerator Toilet won't hold water.

[bobbg]

I have an issue with the front toilet of our coach (2020 Dutchstar 3736). Out of nowhere, it just stopped holding a water level in the bowl after the flush sequence. The level would just drain out to about 2-3" but does not completely drain. It started doing it one day then started working again the nex, but now it's back to draining out?? Any ideas - nothing in the manual suggests a cause or remedy.

[Old-Biscuit]

water level in bowl is dependent on height of pump discharge pipe...top of loop has to be above water level

Also the Vacuum Breaker device must open after a flush / close when flushing
If stuck closed a siphon action can occur
Device comes off pump discharge pipe


Which model do you have?

[Suburbazine]

Look behind the toilet, there will be a U shaped pipe rising to the top edge of toilet. That's your drain pipe. It will have a small plastic valve (looks like a few holes with a silicone plunger sticking up) that will be at the apex of the pipe. Debris gets trapped in this thing and causes the bowl to drain down. You can either push the plunger down a couple of times with your finger (usually fixes it) or you can use a can of compressed air to blast through the holes.

[alank]

Everything Old-Biscut says is right. Something I read long ago was about that discharge tube not being properly tied up in an upright position on the Newmar forum. You'll need to take the side cover off to see the discharge tube and vacuum breaker.

[Mr. T]

I've attached a picture and parts list for reference.
Look at part 10 for the tube referenced above

[1averageguy]

Look behind the toilet, there should be a white circular valve with "pie shape" lines across it. It'll be the upper most point of the plumbing, almost the to the ceramic. That valve breaks the vacuum on the system when it flushes. Gentle (but firm) flick it a few times with your finger while flushing it. It should free up the valve and stop it from siphoning the water out when it's done.

[mmstump]

Originally Posted by Suburbazine

Look behind the toilet, there will be a U shaped pipe rising to the top edge of toilet. That's your drain pipe. It will have a small plastic valve (looks like a few holes with a silicone plunger sticking up) that will be at the apex of the pipe. Debris gets trapped in this thing and causes the bowl to drain down. You can either push the plunger down a couple of times with your finger (usually fixes it) or you can use a can of compressed air to blast through the holes.

This is most likely the cause of your issue. Word of caution (from experience) be sure to hold the little silicone/rubber tab from the top before doing anything that could push it down into the tube. I use tweezers. If it goes down in the tube you won’t be able to use the toilet and will either need to replace the tube (which is surprisingly expensive) or need some professional dental tools to fish it out…(ask me how I know) ��

[ScotS]

Just went through this. In my case it was not the air break valve, or whatever it's called. It was the macerator pump shaft seal, which leaked pooh water on the TV in the outside TV / water tank compartment, which is below the toilet on my model. Not saying this is the issue with yours, but check it while you are in there. If the pump is the issue, don't buy it from Newmar or NIRVC, they want North of $1,000 for it. They are available in the low $400 range and list is in the high $500 range, which in my opinion is way more than it's worth, very simple design and parts.


This also could explain the crappy reception on that TV , I digress ...

[Hawkeye]

[QUOTE=ScotS;6417729]Just went through this. In my case it was not the air break valve, or whatever it's called. It was the macerator pump shaft seal, which leaked pooh water on the TV in the outside TV / water tank compartment, which is below the toilet on my model. Not saying this is the issue with yours, but check it while you are in there. If the pump is the issue, don't buy it from Newmar or NIRVC, they want North of $1,000 for it. They are available in the low $400 range and list is in the high $500 range, which in my opinion is way more than it's worth, very simple design and parts.

I am going thru this now, and have a little water under the stool, is that a indication its the pump seal or does the vacuum valve leak water when plugged?
How hard is it to pull the stool out to replace the pump?

[Hawkeye]

Where is the best place to get the pump

Thanks for your help

[Country Road]

Originally Posted by Hawkeye

Where is the best place to get the pump

Thanks for your help

Just Google Dometic macerator pumps and you’ll get many choices.

[alank]

Originally Posted by Hawkeye

How hard is it to pull the stool out to replace the pump?

When I did mine, I just took the side covers off, loosened the clamps and pulled the motor out, and electrical plug. New one went in same way, didn't remove the stool.

[Hawkeye]

Thanks for the help, I'm guessing the stools are like everything else and you can't shut the water off to them without turning the whole coach off?

Thanks

[Hawkeye]

If the vacuum breaker valve is plugged, would you have water under the stool?

Thanks