Holding tanks not draining through macerator

Good morning - can’t find any posts related to this (at least my searches aren’t bringing anything up). Neither holding tank will drain through the macerator system. I know there is a clog somewhere, and the tanks drain using the 3” hose, but when I try to drain using the macerator nothing comes out of either tank. I can hear the autodrain valves opening and closing, so the problem doesn’t appear to be there. The macerator is spinning, so I don’t think it’s in the macerator itself. Any thoughts/suggestions? We’re out on the road, so my resources are somewhat limited. TIA.

Are your tanks clean now? Meaning have you flushed and drained thru your 3” line? Once flushed I think I’d start by removing the macerator.  It’s very easy. See if the entry to the macerator itself is plugged. It’s not a very large opening to the blades so a clog could be there. If that’s not clogged my next step would be to have the valves open to the tanks and using a hose with a jet nozzle back washing from where you pulled the macerator.  I won’t be surprised if you find the clog is at the opening of the macerator.  There’s a choke point there from the 3” inside pipe diameter down to the opening to the blades. Although extremely doubtful it could be in the hose ,if you don’t find the clog in the other two areas jet out the hose from the macerator. I can’t imagine it being clogged after the macerator. I’m just throwing out possibilities even if remote.

Removing the macerator only requires a Phillips and a flat head screw driver if my memory serves me.  Doesn't always serve me anything any more but in any event not many tools are needed

Hi George,

I never heard anyone have your problem. 

Being that you have a 2014, I think you have the same macerator as our 2007.  If so, it looks like this.

Pay no attention to what is shown broken in the two pictures.


Note the opening.  I wonder if there is a large blockage right here.


Based on the description of your problem, try this.  Fill your gray tank with fresh HOT water along with a good amount of soapy dish water to create a penetrating slippery solution to loosen whatever is blocking the macerator input area.  Close the black tank valve and open the gray water tank valve but keep the 3" gravity drain capped so the hot soapy solution can soak the inlet of the macerator.

Of coarse there is no guarrantee it will work but surely worth trying.

Another thought would be to run the macerator backwards by switching the two wires.  I don't recall how easy it is to access those two terminals while everything is fully assembled.  You might need a bucket of water to draw from.  I never tried this one either...it's all theoretical.

One thing I do know is that the pump will not get damaged if run backwards.  I know because I initially wired my replacement macerator backwards by following the colors of the wires.

Thanks guys. I think I’ll try Ron’s method first - seems to me like it might be less messy. Plus I have a habit of taking things apart and not getting them back together again 🙄. Luckily we are moving tomorrow to a campground with full hookups, and will be there for a couple of days. I will keep you posted.

 

Ron’s pic shows exactly what I was referring to. From 3” down to that small choke point opening.

Here is another idea running the pump backwards.  If you have a drill handy, attach a flat blade screw driver bit on it and run the pump backwards that way as shown here.

Ron, I guess it’s worth a try but if the plug is at the choke point it’s not going to do anything. My understanding is the pump runs. If it spins it’s not clogged at the impeller. Do you think maybe running backwards will create a back pressure?

Do you think maybe running backwards will create a back pressure?

Good question.  I imagine you have a fair chance of it.  Be sure to place your macerator hose in water to provide hydro-force to pop out what we assume is a blockage there at the macerator.

Pressurizing the macerator hose with city water is yet another thought.  Just make sure it doesn't expand to the point of getting damaged.  If only you could keep it in its collapsed state for increased back-pressure.

Keep in-mind I am throwing crazy ideas out here to consider.....nothing I say has been field tested.

Ron, sounds like a hard approach.  One nut, two screws, slide the macerator out, dumping in a bucket. If the blockage is right there it’s done, bolt it back up. If it’s not your now open to flush with a hose that 2-3 feet from the macerator to the three inch dump that’s working.   He knows it’s not beyond that as it’s working to that point.  As far as the hose goes, easy to check, just run a garden hose thrust it with pressure.  No need to run the pump at all. Leave it off or run, open valve to black tank.  Prob going to be messy but it’s all your own anyway. Nothing to worry about.

There is one other possibility I can think of. The impeller could be stripped. The pump would still run with no discharge. My original macerator had all the impeller blades gone but one when I changed it out. Could be it stripped and shaft is spinning with out turning the impeller?
Just a possibility if no blockage is found.

Ah yes.....

Maybe it lost all its rubber flapper impellers.  I had a few missing when replacing my macerator.  But in my case, the failure was caused from the motor siezing up from one of the 4 bolts corroding so badly that it broke and jambed up the macerator blade.  When I took the macerator apart, I also noticed a few impeller rubber flappers missing.

I am asking out of ignorance because I have never had a macerator problem but if part of the blades are missing don't they make a heck of racket when the pump motor is turned on??

I am asking out of ignorance because I have never had a macerator problem but if part of the blades are missing don't they make a heck of racket when the pump motor is turned on??

I did not notice a change in the sound of the pump with a rubber impeller blade or two missing.

Done working.   When mine went south I had one and a half blades left if I recall. The blades are not metal and they are flexed pretty snug against the inside of the housing.  If there was a difference in sound I wasn’t aware of it. Quite possibly because it probably didn’t lose blades all at once so any change in noise level wouldn’t be noticed if any.

Mine got to where it took a huge amount of time to empty and very slow and wouldn’t pump up a grade. In this case if it has stripped from the shaft the motor spins and nothing gets thru. If all the blades are gone I would have expected there to be some gravity discharge. How much, no clue. 

Ron and I are throwing out wild guesses based on the only area left it can be is the last couple of feet to the macerator. I’ve had mine apart several times. Changing out valves and most recently removing the thermal switch from a macerator that has run dry protection. It’s a pretty simple set up and only a few possibilities based on what info we were given.