blackwater tank not fully empty

JBM3M · 06-05-2022, 06:22 AM

I have 1 black and 2 gray water tanks. The drain handles are marked wrong which I only just learned. (I put on a device at the hose hookup that has another shutoff as one of the tanks is leaking at the shutoff valve and that has a slight clear section so I was able to determine which one had the chemicals, thus locating the error in the handles.) Not a huge deal.

But we are sitting in RV park with RV level and the drain open for 3 days now and it still shows 1/3 tankful for the black tank. I am pretty sure the black tank is the one leaking and therefor am assuming the valve is not operating properly.

This is not a huge emergent deal to me, will work on it when back home, but research is possible at this point.

1) Can folks throw out some ideas
2) How hard to change that valve for the black tank if that is the issue?

Again not a major issue as the two of us cannot fill the black tank in the 2 day return trip.

RollaMo · 06-05-2022, 06:33 AM

Quote:

Originally Posted by JBM3M

But we are sitting in RV park with RV level and the drain open for 3 days now and it still shows 1/3 tankful for the black tank.

Much more likely, the gauge is not reading accurately.
RV tank gauges are just notoriously inaccurate.

bsmith0404 · 06-05-2022, 06:36 AM

If you do a search on black tank sensor you will find info all over on this site as well as the internet. The sensors are notoriously inaccurate and it is very common for the tank to show that it is not empty even when it is. The sensors are just 3 small wires inside the tank. If anything gets hung up on them, tp or other stuff, it will show the tank is full to that level. Also, the valves are notorious for leaking past them for the same reason. The fix that you have done with a secondary valve is the best fix for that as well.

**flybouy** · 06-05-2022, 07:26 AM

"But we are sitting in RV park with RV level and the drain open for 3 days now and it still shows 1/3 tankful for the black tank. I am pretty sure the black tank is the one leaking and therefor am assuming the valve is not operating properly."

This is the worst thing you can do for a blck tank and IMO a gray tank if your not using a washing machine. With the tank open the liquids will run out of the tank while the solids set on a dry bottom. Water is needed to keep solids "afloat" and carry them away when draining the tank.

**sourdough** · 06-05-2022, 08:22 AM

Those sensors are worthless IMO. I haven't used them for years as they simply aren't right....and I've been unable to make them "right" no matter what I do so I ignore them.

Leaving the drains open is an invitation to problems IMO. Tried it once and had so many issues I've never done it again...and had no problems. You want to dump black, gray 1, gray 2 etc.? Pull the handle, watch the clear section, when the water quits running out it's empty. Close the handle.

When you leave those drains open the bottom of the tank has nothing in it. Anything that drops into the tank just sits there - black tank is a real issue. Time to go home you close the valves, go home, put up the trailer and all those solids dry up into bricks. Next time out you just build up and make the brick bigger until something quits working. Not good.

JBM3M · 06-05-2022, 09:05 AM

First of all, I know not to leave the black tank open, was wanting to see if it made a difference. We have the trip home, about 650 miles of curvy hilly country, so it will get swished around.

Yes I normally do the black and then the gray tanks. I wondered if it was just the sensors, any other RV I have had they didn't work at all.

Thanks

**chuckster57** · 06-05-2022, 09:14 AM

Im at the other end of the sensor debate. They work with the proper Maintenace. Valves leak for a variety of reasons and foreign material is just one. Changing the seals isnt a big deal, you just have to know what brand of valve you have.

**JRTJH** · 06-05-2022, 10:39 AM

I'd have to ask:

Why would it matter if the 1/3 full sensor is working or not?

You don't (or shouldn't) be dumping a tank that's only 1/3 full and if the 2/3 and 3/3 indicators are working, you'll know when the tank is full and with the valve, while you're standing there dumping the tank, you know when the tank is empty (when brown trout quit swimming downstream)....

So, other than filling a space on the indicator panel, the 1/3 LED is more or less "just decoration" anyway.....

I get it, it's a new trailer and it ought to work.. But .... what's the "real purpose of a 1/3 sensor anyway ???? You don't dump using it, you don't fill using it, you don't change any toilet use by using it, it's just, well, there to bug you when the led won't go out..... Keystone's "revenge light" ????

Z71 · 06-09-2022, 08:52 AM

I have a 24RDS Cougar with the In-Command system, We have never done a number 2 in the toilet or used paper products (small sealed waste can next to the throne) and shortly after purchasing and using the camper the tank levels on all 3 tanks always show content even after dumping.

I consistently use Happy Camper in all 3 tanks and usually pre-wash dishes outside. When I dump the tanks they usually show full and I always us the black tank flush.

Talking with the dealer I am usually told forget what the indicated levels are and that most of the time they are wrong anyway. Just make note of your routine and begin to know how long you need to go before dumping. Not very scientific I guess. I have been told to resolve the problem they would need to removing the lower covering and replace the sensors which would only again fail probably within a short time. Seems they could come up with a better system.

**sourdough** · 06-09-2022, 09:03 AM

For many decades RVs did not have sensors on the tanks, they just filled up and you dumped. In a short time you learned how to tell when to dump before the contents began backing up into the trailer. I suppose the move to sensors was to help folks identify when to dump, a noble cause, but the end result still leaves us back where we used to be. That wasn't a problem "back when" since the sensors didn't exist and really isn't a problem now - just watch those tanks and learn how to read/hear them....they really do "talk".

**JRTJH** · 06-09-2022, 10:00 AM

Quote:

Originally Posted by Z71

I have a 24RDS Cougar with the In-Command system, We have never done a number 2 in the toilet or used paper products (small sealed waste can next to the throne) and shortly after purchasing and using the camper the tank levels on all 3 tanks always show content even after dumping.

I consistently use Happy Camper in all 3 tanks and usually pre-wash dishes outside. When I dump the tanks they usually show full and I always us the black tank flush.

Talking with the dealer I am usually told forget what the indicated levels are and that most of the time they are wrong anyway. Just make note of your routine and begin to know how long you need to go before dumping. Not very scientific I guess. I have been told to resolve the problem they would need to removing the lower covering and replace the sensors which would only again fail probably within a short time. Seems they could come up with a better system.

There are several "better systems"... Airstream uses one, replacement cost for parts is around $300. NewMar diesel pushers use a similar system as Airstream but costs around $500 for parts... Airstream retail pricing starts at around 2-3 times the starting price for Keystone trailers and NewMar DP's start about 5 or 6 times the price of a top of the line Keystone Montana....

So, to keep Keystone trailers "cheaper than the luxury land yachts" cheaper components (some that don't work very well) are used.... I suppose that same could be said for the 7500 watt diesel "quiet generator" on that NewMar and a 200 watt solar panel on a Keystone as well..... You get what you pay for.....

Z71 · 09-09-2022, 08:26 AM

I wonder if anyone has done a sensor upgrade on their tanks without removing the lower cover completely. It would seem easier to cut an access panel in the lower covering and them make it so it could be easily removed and re-installed whenever it was necessary.

I tried calling Keystone to see if they could provide any information on this but as usual no help and "take it to a dealer" was the answer of the day.

Totally removing the under side cover is out of the picture especially the way Keystone put it in place with some kind of nail thing that goes thru the bottom of the cover into the frame, I would never be able to get it properly secured. And before everyone chimes in, Yes, I know I should just ignore the incorrect readings these cheesy sensors provide.

travelin texans · 09-09-2022, 03:50 PM

Quote:

Originally Posted by Z71

I wonder if anyone has done a sensor upgrade on their tanks without removing the lower cover completely. It would seem easier to cut an access panel in the lower covering and them make it so it could be easily removed and re-installed whenever it was necessary.

I tried calling Keystone to see if they could provide any information on this but as usual no help and "take it to a dealer" was the answer of the day.

Totally removing the under side cover is out of the picture especially the way Keystone put it in place with some kind of nail thing that goes thru the bottom of the cover into the frame, I would never be able to get it properly secured. And before everyone chimes in, Yes, I know I should just ignore the incorrect readings these cheesy sensors provide.

I'd pry those nail type fasteners out, grind off if necessary & replace with self taping screws.
But either cutting an access hole or removing the underbelly seems an effort in futility where the sensors are concerned.

Jofar33 · 10-20-2022, 03:54 PM

While reading this issue, and the thought occured, could a section of that underbelly covering be removed..then the edges fastened to any crossmembers forming a box like section. then a piece of fiberglass..hatch-like cover be installed---fastened--maybe hinged so an easy access to the tank connections--sensors be created?
I have a leaking BW valve on my Carbon 33 TH that needs to be fixed. Or as mentioned install the twist on valve on the end as a 2nd valve. It could be just a cable issue as some have had here. I have also read about driving the dump side trailer wheels on blocks to tilt the trailer so any liguids in the tank will not drain out as the valve is being replaced. My sensors are questionable as well. I fill up the BW tank with a hose till i see the water in the tank---then dump. Then use my flush out system to flush out again till the water runs clear for a few minutes. then close the valve and let the water fill the tank for another 2 min...leaving a few gallons in the tank.

**JRTJH** · 10-20-2022, 06:27 PM

Quote:

Originally Posted by Jofar33

While reading this issue, and the thought occured, could a section of that underbelly covering be removed..then the edges fastened to any crossmembers forming a box like section. then a piece of fiberglass..hatch-like cover be installed---fastened--maybe hinged so an easy access to the tank connections--sensors be created?
...

Most of us do "pretty much that same thing" by cutting a 3 sided access hole and use the remaining side as a "hinge" to fold down the coroplast "flap". Then, when the reason for the hole is finished, just use two or more zip ties in holes in the flap and the adjoining intact coroplast. Once the flap is secure, just seal the cut out with scrim tape and it's "good as new"... Then, if you ever need access to that area again, you've got an access hole already cut, just pull away the tape, clip the zip ties and fold down the flap...

Most of us cut the two sides and the rear, so the flap "folds to the front". That way there's less chance of wind catching the flap and pulling it away as well as less chance for water/rain to "scoop into the belly" if the tape should leak or be torn away.

dutchmensport · 10-21-2022, 05:57 AM

Quote:

Originally Posted by JRTJH

Most of us do "pretty much that same thing" by cutting a 3 sided access hole and use the remaining side as a "hinge" to fold down the coroplast "flap"....

Bingo! Spot on! That's exactly how I did it. Only mine was a repair on the 1.5 inch grey water ABS black pipe. But, that's exactly how I made the access! And it worked great! Hopefully, I'll never have to access it again.

Jofar33 · 10-21-2022, 07:34 PM

Ok, I see how that can be done. I just thought maybe that covering wouldn't hold well with tape only. Using Gorilla Tape along the cut edges could secure it I guess. I'll give that a try. Not sure if I will need to replace the gate valve yet. It could be just the cable is the problem. Thanks for the reply.

**chuckster57** · 10-21-2022, 08:01 PM

Gorilla tape is good stuff, but it will peel and become a sticky mess. Scrim tape will hold tight for a LONG time and get sticky.

**JRTJH** · 10-22-2022, 06:22 AM

Here is one source of SCRIM tape: https://www.amazon.com/Mobile-Flex-P...s%2C123&sr=8-3

It's relatively expensive, but much cheaper than new coroplast or a plastic access hatch to install in a cutout....

Thinking "outside the box" for a moment, IMO, this is one good application for Eternabond tape. It's "permanent", sticks to everything, doesn't pull off easily, possibly won't pull off "ever"... And, if you need access in the future, you'll likely want to cut the eternabond tape along the original coroplast "cut line" rather than try to peel the tape off the coroplast.

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