2018 Vista 29VE Gray tank size and Mopeka water sensor question

[burt6274]

Hi,



We bought a used 2018 Vista 29VE a couple of years ago, and the tank sensors worked reasonably well up until a couple of months ago.

I know that is a common issue for everyone.

These are the external stick on sensors, not though the tank wall.

The Black and Fresh sensors are still working as well as any of crappy LED third's sensors do.

The issue is the Gray tank. It started to be intermittently showing 1/3 full even when totally empty. Sometimes it would bobble between empty and 1/3. But finally is stuck on 1/3 all the time.

I've included more details below, but I have a couple of basic questions:

1 - The build sheet says that the Gray tank capacity if 61 gallons. Is that including the 10 Gallon external tailgate package holding tank, or just the main Gray tank. The build sheet doesn't list the 10 gallon extra tank, but the manual for the MH does.

2 - Has anyone else installed the Mopeka Pro water sensor on their Vista, or similar Winnebago model? If so did you encounter a similar issue where you needed to over stated the tank height in their app to get accurate readings?

I have cleaned the Gray tank 4 times, trying Dawn the first two times, and then Digest it the last two times. Nothing worked to resolve the issue. We have been very careful to not but a lot of grease or food scraps down the drain since we have owned the RV.

I have made sure that there are no wires that have fallen down near the sensors. So I've pretty much covered all the basics that usually might apply.

I know that the main go to for this is the See Level system, but I was looking for a slightly less pricey solution at least for now. Also installing the See Level panel would be a big pain to do right, and that would be effectively installing over the existing LED display area on the Winnebago panel. Doable but would need a fair amount of work.

I had installed the Mopeka LP Pro sensor a while ago and that is very accurate on reporting the % full status of LP.

So I got the Mopeka Pro water sensor and installed it on the bottom of the Gray tank.

As near as I can determine the tank height is around 7 inches or so. But when I use that tank height in the Mopeka app it appears to be off, a lot. I tested this by adding 6 gallons of water to the empty Gray tank.

Then with the tank height set to 7" found that it reported the tank was fuller than expected.

I would have expected about 10% but instead it reported close to 30%. By adjusting the tank height in the app to 17 inches then it did report 10%.

I increased to 12 gallons total in the tank with the same issues where I need to significantly increase the tank height in settings to get close to an expected reading of 20%.

Thanks,
Burt

[Morich]

I do not know that system but I suspect the errors in reading may be due to a basic design question?
If you place a sensor on the bottom of the tank, what does it read? I might guess it read the amount above the sensor? Correct me if not right on that!

But my theory is that it is having trouble reading the total volume when the height of the contents changes.
The problem is that the tank is not just a rectangul but has a sloping floor. A one inch dpethy at on point will not be the same reading doubled as the contents get deepr but also wider!
That may not make sense but looking at the shape of the tank makes me think reading from below is not going to work when the floor slopes?
I actually see much of the reason for any sensor being prone to being off at some point, so calling out "about 1/3, about 2/3, is about as good as I see happening!


At this time, I see it as two options. We can have a tank with a simple shape to read better or we can have a tank with the max volume in the given space and which drains well.

But It seems we can't currently have both!
I find the sensors do work better than they used to but not much!

[burt6274]

Thanks,

That's also a possibility. When I tried to access the 3D parts applet on the Winnebago website yesterday it was throwing a 500 Server error. I'll see if it is behaving better today.

Looking at the physical tank, the parts that I can see without pulling panels it doesn't appear to have a slope, but that is the wet bay side, so the diagram shows a shallower depth at the shower end, which I can't easily see without pulling some panels off on the passenger side basement area

That said, the sensor is at the bottom of the tank in the wet bay area which would be the deepest part of the tank. So in that case it would tend to fill up a bit more in that area, so that may indeed be the cause of the problem.

If so I should be able to tweak the tank height setting to get a reasonable compromise. I'll test that out on our upcoming trip.

BTW, that same problem would exist with the stock Winnebago external sensors since they are stuck on the side of the tank at the wet bay area facing the door. So I would not be any worse off with the Mopeka sensor located on the bottom, especially since it accurately reports that the tank is indeed empty after dumping.

[Morich]

Yes, the sensors are just a kind of "quessimate" to me and not really precise when working their best.
Wehn we have had them that never worked, we just went with either being sure we dumped in time or checked the sides as they were the white plast that we could see enough to tell the levels.
For a while we had one that somebody had invented a float gizmo that stuck up under the bed but that suffered from the sloping floor and was not really too close. But it did teach me where the slope does throw it off!