Tuesday, November 28, 2023


The RV’s macerator pump quit, valve is leaking, black tank is full. Help!

Dear Dave,
My macerator pump motor failed and needs to be replaced. The problem now is a leaking waste valve and a full black tank. I can’t isolate the pump. How do I evacuate the black tank to replace the pump and install a new valve? —Michael, 2019 Winnebago Era

Dear Michael,
According to the Winnebago specifications, you either have a 70M or 70X, as they are the only two models of the 2019 Era that has a macerating pump for the toilet. In your case, the macerating pump or grinder pump, as it is often called, grinds the solid waste into a liquid type state. The dump valve is only 1 1/2” due to the space confinements, as most dump valves are the larger 2 1/2”.

According to the 3D drawing, the pump is located downstream of the black water tank and pipe with a cover.


Here you can see the tank behind the green cover and the pump is the yellow box in the middle. The drain valve is at the tank with a remote cable and handle by the drain pipe, which looks to be located on the curb side.

It sounds like you have two issues: the pump not working and the valve leaking. If we look at the drawing from the bottom, we see the 3” pipe and valve location just before the macerating pump, which I assume is the leaking valve.

If you have access to the pump, you should be able to disconnect the green fitting just after the valve and before the pump and dump it from there. But it would be a very messy process unless you could get a dump “sock” around the pipe.

Get a sewage pump service

Since it looks like the toilet dumps straight down into the black water tank, I would suggest getting a sewage pump service to empty the tank through the toilet. Here in the Midwest we call them “Honey Wagons.” They are hired to come to rallies and campgrounds that don’t have dump stations and empty the tanks through a large hose with a pump and storage tank. Your local Sanitary District has a large version of this in a pump truck that empties sewer and drain lines that get clogged, as well.

I would check with your local campground or even RV dealer or service center to see if they have someone they use. Then you can work on the valve and pump. You can find the 3D parts page here.

 You might also enjoy this from Dave 

Can I swap my gravity toilet for a macerator toilet to help with dumping?

Dear Dave,
My fifth wheel has a typical Thetford gravity-style toilet, the kind that drops the stuff straight down to the tank. Are there any macerator toilets that would be a direct replacement? I am hoping to grind up the solids and paper before it enters the black tank. I am aware of the macerator options at the black tank drain but would like to make it easier for people renting my RV to drain the black tank. Thank you! —Craig, 2004 Keystone Sprinter 297BHS

Read Dave’s answer.

Dave Solberg is a leading expert in the RV industry and the author of the “RV Handbook.”

Read more from Dave here


Dave Solberg
Dave Solberghttp://www.rv-seminars.com/
Dave Solberg is a leading expert in the RV industry and author of the “RV Handbook” as well as the Managing Editor of the RV Repair Club. He has been in the RV Industry since 1983 and conducts over 15 seminars at RV shows throughout the country.



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Mike R (@guest_255380)
1 month ago

Ok it’s messy get your gloves on. Take your wet/dry vacuum and start sucking the nasty out through the toilet. Then dump the nasty in your home toilet. *** This is best done when you spouse is not at home.

Jim Johnson (@guest_254609)
2 months ago

My macerator is external. Mostly I use it to dump tanks at our house following a trip or if moochdocking at a family or friend’s house. While it works great, it is no faster, and perhaps a little slower than a gravity only dump due to the time to connect, disconnect and flush/store the 3/4″ contractor grade hose. If you need the solution, great, otherwise save the money.

I found that a little squirt of silicone spray into the exhaust port to coat the impeller after each use avoided ‘dry seizure’ issues – likewise treating the rubber O-ring at the intake made for easier mount and especially dismount. However, I had to teardown the unit this summer. I found that just a little bit of hair had wrapped around the working end of the motor shaft. The macerator is also used to pump gray water. We use hair filters in the bathroom sink and shower, but just that little bit that still got through was binding the motor shaft.

Stefan trestyn (@guest_254608)
2 months ago

Port a potty companies will pump it out

Dr4Film (@guest_254599)
2 months ago

Thank God that my 06 Monaco Dynasty coach that I purchased last year already had the macerator removed. I did have to remove both valves and the T, then install a two new valves with a standard RV T that would receive the 3 inch TV sewer hose. Macerator’s are a good idea until they aren’t when they don’t work. Never had any problems when using the sewer slinky that provides a good WHOOSH! I do own a portable macerator that I had purchased from a person who had used it once. I still have yet to use mine but have it if I am presented with a situation that requires it.

tom (@guest_254587)
2 months ago

At the end of the motor shaft, there should be a slot for a flat-headed screwdriver. Insert screwdriver and turn the shaft a few turns. Your unit may be stalled, not broken. Works for me. Mine isn’t buried, so easier to get at.

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