Drip from top of black tank

[rtwright68]

Hello,

I have a 2017 Minnie Winnie 31K and tested out the plumbing yesterday after winterization (first time since we bought it last year)

Last October I blew the lines out and the tanks were essentially empty (poured pink stuff down the drains as well.

Yesterday I filled the water tank about 1/3 and tested the pump as well as the city connection, no leaks.

Everything works great. Put water in the toilet and flushed a couple of times. I noticed a drip coming from the top of the blank tank after that (bad location, hard to see where its coming from).

I left the pump powered on for a while and never heard it start up again so I think I'm good with any potential plumbing leaks.

I checked the toilet and it wasn't loose but I went ahead and tightened the bolts a bit. Still dripped after that.

The dripping stopped after a while so I'm wondering if there is a bad toilet seal to the tank. Hopefully the black tank isn't cracked. The tank straps are tight and secure so there hasn't been any movement.

Not sure what to check or method of fixing?

Thanks in advance!

[Morich]

It's coming from somewhere and we can't spot where? YUP! Normal head scratcher!

But Winnebago has come through with a great helper for looking through those walls to see what "might" leak.
This is the one I use most often to get a look without having to crawl around for an hour:
https://catalog3d.winnebagoind.com/menu/Parts.htm

Would I be a fussy "XXXXX" to ask what serial number you have? Sometimes that is needed to get down to exactly which build , early or late, so I'll let you choose! I've been called a jerk for asking that question!
But the info you can get is so helpful, I still recommend it to folks!

One build of your RV shows this for black tank top:
There are only a couple suspects for leaks at the tank top and tanks have water at the bottom to freeze, so not likely to crack at top.


But the one that can throw us is where a supply line passes over the tank to drip off looking like a tank leak!
So you have to look at the fresh water lines in that area?
Maybe like this stool supply that "might" be right over the black tank?


Hard to actually relate fresh and drain drawings when on seperate places but this idea may help.
DO keep in mind that this may not be the build for being exactly right for your RV ( I DID NOT ask for the serial number! ) !

I play in that drawing group a lot so, I might pass some hints along if you are having trouble spotting things or moving around in it!
Before zooming we can pick a point on the drawing to keep centered as we click and drag to turn, scroll to zoom, or change the view from front, back, top, left, right. Click on X symbol before zooming, then click on the part you want to keep centered!


Click on item in drawing to highlight in yellow on parts list or the other way to click on list to highlight in yellow on drawing. Clicking repeatedly on part in list will make it flash yellow to help spot small parts we can't find!

[rtwright68]

Richard,

Thanks so much for the info! I hadn't considered a supply line but I will do some experimenting tonight.

Will hook up the city supply and see if that causes a drip. Then will try the tank file and let it run for a bit.

I also have a tiny camera that I used in previous car repairs that I will use to see if I can discover the source of the leak.

[Morich]

Since the stool that "seems" to cause the problem is way in back and pretty far from the black tank, that may be less prone to being the problem? But that can be part of the confusion game as water may lead on top of something and run ten feet bewfore coming our to be seen!

considering how little water we use when we flush, compared to what we have at home, and then the way that pipe drops the solid waste into a pretty shallow tank, The idea of a tower building up may be one I lean toward.

If you can get a hose into the bath and find one of the gutter cleaning tools that has a head that can swivel at different angles, puttin gone down the stool and aiming for that corner, might be one of the quicker things to get that idea sorted out?

[rtwright68]

Ok, I did some more experimentation tonight. I waited several minutes between steps.
1) I poured nearly a gallon of water from a jug down the toilet and flushed. No drips.

2) I hooked up the city water supply to the RV and ran some water down the kitchen and bathroom sinks. No drips. I waited a bit to make sure that there were no leaks from the pressurized water supply.

3) I then flushed the toilet as you normally would using the city supply. A slow drip started almost immediately. After a bit the dripping stopped.

So, I am wondering if there could be something broken inside the toilet. Its odd that once I flush the toilet with the foot pedal the drips start.

I took some pictures above the tank with my iPhone and there is a crap-ton of spray foam. I will see if I can upload them to a photo album.

The floor all around the toilet is bone dry as well. Weird!

[rtwright68]

[Morich]

OUCH! I've done it again and totally screwed up my post 4 above! Totally confused two different situations on looking for leaks on different RV! You may have wondered what the H is he talking about??
This post has a drip from the top of the black tank and he has found a black water drain line has come apart at an el where it finally turns to drop into the tank.
different story but they merged in my cluttered mind!

Now if I gety my head straight?
The info that it seems to leak when you flush but stop shortly after makes me lean toward a leak in the stool or very close to the flush valve.
Think of the valve as hold water when closed but as you operate the valve, it lets water through and the water moves in some form of tube or channel up an into the stool bowl. My thought is that there is some form of leak that is between the vavle and where the water comes out in the bowl??
Leaks as water is actually flowing through that tube or channel but stops when the valve closes and no more water goes through that spot!!
So you may be looking at what is meant to go into the bowl but it sprays out inside the base of the stool but not where it is meant to be inside the bowl?? So the leak may actually be fresh water that never gets into the stool itself to become black water, even though it gets color and may look black by the time it leaks out.
If you have info on what brand and model of stool, there is a good chance that drawings of the parts and maybe something to point to tubing or fittings that might leak, might be found online??
I'm thinking some small part like a tubeing loose or split! Not a total stool replacement.

See if that makes more sense for what you have. Gotta be better than my other post meant for the other folks. Shish!!!

[rtwright68]

Originally Posted by Morich

OUCH! I've done it again and totally screwed up my post 4 above! Totally confused two different situations on looking for leaks on different RV! You may have wondered what the H is he talking about??
This post has a drip from the top of the black tank and he has found a black water drain line has come apart at an el where it finally turns to drop into the tank.
different story but they merged in my cluttered mind!

Now if I gety my head straight?
The info that it seems to leak when you flush but stop shortly after makes me lean toward a leak in the stool or very close to the flush valve.
Think of the valve as hold water when closed but as you operate the valve, it lets water through and the water moves in some form of tube or channel up an into the stool bowl. My thought is that there is some form of leak that is between the vavle and where the water comes out in the bowl??
Leaks as water is actually flowing through that tube or channel but stops when the valve closes and no more water goes through that spot!!
So you may be looking at what is meant to go into the bowl but it sprays out inside the base of the stool but not where it is meant to be inside the bowl?? So the leak may actually be fresh water that never gets into the stool itself to become black water, even though it gets color and may look black by the time it leaks out.
If you have info on what brand and model of stool, there is a good chance that drawings of the parts and maybe something to point to tubing or fittings that might leak, might be found online??
I'm thinking some small part like a tubeing loose or split! Not a total stool replacement.

See if that makes more sense for what you have. Gotta be better than my other post meant for the other folks. Shish!!!

Haha, thanks. No worries! Appreciate the reply. That makes perfect sense that it could be something leaking in the foot valve which would let the water drip outside of the toilet flange/seal. I will have to get the part number from that toilet and see what info I can find.

[rtwright68]

Had trouble finding the label, but in the RV manuals and searching online it appears to be a Thetford Aqua Magic Style II (high profile).

[Ray,IN]

Some commode mfgrs. put an ID sticker on the pedestal under the bowl, which is hidden by a plastic cover.
I would think any black tank leak from the top would require the tank to be completely full first, unless the 3" PVC down pipe is cracked.

[Morich]

I'm thinking this will require some stool teardown work to get where you can see the valve connected to the flush pedal, etc. My idea is that there will be no leak when setting without use but as you flush the valve lets water go through to some line which carries it up and into the bowl. I feel there is a leak after the water leaves the valve and before it get into the bowl!
That leaks lets the water drip or run down the outside of the tube where the waste goes down but when it gets to the floor, it finds a way to drip on through and land on top of the black tank. Not a spot where you can see it easily but it then runs to the side and looks like a leak in the black tank top?

Maybe something as simple as a connection not tight on the output side of the valve---but a pain to get in to tighten on some stools! Or if it is a flexible tube, maybe the end that is supposed to put the water inside to flush is pulled out a bit and part of the water goes to flush but some flies out the side??

If you have a Thetford stool owners manual in the big bag, does it have an exploded drawing which shows the valve and maybe how the water gets from the rear inlet, through the valve and into the bowl?