Black Tank continually registering full

Irishman2014 · 04-25-2019, 04:55 PM

Hello all. We have a 2014 Cougar CCH 27RLS that we purchased from a dealer about 2 months ago. We've used it a couple of weekends and for the most part its fantastic and we really enjoy it (first timers). There's a control panel that is for turning on the lights, HW tank, water pump, slide out, etc. That same control panel also tells us how full our water tank, gray tanks and black tank are. I've dumped our tanks (black first followed by the two gray tanks). I know that they are emptying because you can feel the water rushing out through the dump hose. I then rinse out the black tank by utilizing the built in spray system (keystone calls it "no fuss flush kit"). When I check the status of the tanks on the control panel it shows the gray and water tanks are empty, but the black tank is 3/4 to completely full. Anyone run into this before? If so, how did you correct it? Thanks in advance for your help.

KeithInUpstateNY · 04-25-2019, 05:02 PM

If you search "black tank sensor" you will find tons of threads with a multitude of ideas on how to deal with it. Long story short, the sensors read from the top down, so if there is something stuck to the top (full) or next (3/4) sensor that is what it reads. Many of us just don't rely on them.

Tbos · 04-25-2019, 05:05 PM

The tank meters routinely are inaccurate. There is probably some TP stuck on it. If your sure it’s clean then it will be ok. If you don’t use it for a week or so the sensor may dry and work until it gets wet again. Enjoy your new rig.

rjrelander · 04-25-2019, 05:22 PM

Ours is always out of whack as well. You could put a piece of black tape over the display when you dump, then peel back the tape a little every time someone flushes.

**chuckster57** · 04-25-2019, 05:55 PM

Or, you could use “tissue digester”. Use the entire contents, fill the tank. Let it sit for 3 days then drive it around making some hard stops to shake things up. Then dump and rinse. Next aggressive treatment is Rid-X. Let it sit with the tank full for a week or two.

All my sensors on any RV that I have owned or worked on have worked, some after treatments.

FlyingAroundRV · 04-25-2019, 07:26 PM

You could also try the ice in the black tank trick.
Throw a couple f bags of crushed ice down the toilet and a bucket or two of water. Then take the trailer out for a reasonable length drive of say two hours or so. Then dump and flush the black tank and see how that goes.

busterbrown · 04-25-2019, 07:58 PM

As stated before, black tank are notorious for reading incorrectly, even after a good tank fill and flush with an onboard "no fuss flush kit".

Sometimes, it takes a little more physical "encouragement" to get the deposits off the tank sensors. You may want to invest in one of these:

https://www.walmart.com/ip/Camco-Swi...xoCuIoQAvD_BwE

This wand in line with a good amount of water pressure from a garden hose can be placed down and through the toilet bowl valve into the black tank. Let the water blast the walls of the tank by changing the angle of the wand. Just make sure you start with an empty tank.

It's worked for me. I usually do this at the end of each season.

https://youtu.be/xJRvK6rU_-k

For regular black tank maintenance, look up "geo method". It incorporates using a water softener and detergent of your choice. It helps keep the tank clean and reduces smells significantly.

Irishman2014 · 04-25-2019, 08:17 PM

These are all great ideas and a lot of good information that I will use. If I can get the monitor to register correctly I will let everyone know what worked. Thanks very much.

{tpc} · 04-26-2019, 04:29 AM

For what it's worth (likely nothing), ours worked on the 1st trip, and has read empty ever since then. I assume a wire broke or the sensor isn't good, but its been a few years and it hasn't changed. That said we have only had one issue with the black tank being full and not knowing it, and its pretty easy to figure out lol. I think that was during our 3rd ever trip. Since then never been a problem. Fresh and gray work as designed.

Really, the gray is the only one I ever am concerned with and pay attention to. The fresh kinda tells you when its out lol.

labman · 04-26-2019, 06:16 AM

Mine was having issues for a while. I faithfully flushed the black tank after each trip but only for about 5 or ten minutes. While in AZ this winter I let the tank flush for 30 to 45 minutes. After that, it registers correctly.

**JRTJH** · 04-26-2019, 06:20 AM

Like Tony and others have said, You'll know when the black tank is full, no reason to fret over it.....

In every trailer I've had with tank gauges, the black tank sensors have fouled and have read incorrectly. Usually it always reads 3/4 or full. Also, in every trailer I've had, the toilet has a "peculiar sound" when the tank gets close to being full. We have learned to rely on "toilet flushing sounds" to tell us when the tank is nearing full capacity. We've found that the sounds are far more accurate than the gauges ever were.

I'd think that if you pay attention to what your toilet is telling you, you really don't need the gauge anyway. For us, from 1967 until about 1993, none of our trailers even had a tank gauge. We did just fine "back then" and the only thing that's changed is a set of buttons and LED's on the wall that usually don't work anyway. This is one time when KISS really works as well (or even better) than "modern technology".....

jsb5717 · 04-26-2019, 07:18 AM

Agreed, I've had 3 trailers with guages and none of them ever worked. There are far better systems on the market for accurate tank levels. It would be nice if the manufacturers used those rather than the current proven failures.

**chuckster57** · 04-26-2019, 07:23 AM

Quote:

Originally Posted by jsb5717

Agreed, I've had 3 trailers with guages and none of them ever worked. There are far better systems on the market for accurate tank levels. It would be nice if the manufacturers used those rather than the current proven failures.

Probably the biggest reason is economics. The system is cheap and easy to install. See Level comes to mind but at close to $300.00 I don't think people are that ready to spend the higher price. That system is standard on the Allegro Bus we sell but that coach will set you back in excess of $450,000.00

jsb5717 · 04-26-2019, 07:32 AM

Yeah, I was thinking about See Level too. I'm sure it's economics, but when you're spending 40-50K or a lot more on a towable an extra $300 is easily buried in the overall cost. I, for one, would gladly spend the relatively little bit extra for a system that works.

For us it's actually accurate gray water levels that would be helpful. As JRTJH stated, the black water is pretty easy to keep track of.

**JRTJH** · 04-26-2019, 02:01 PM

Quote:

Originally Posted by jsb5717

Yeah, I was thinking about See Level too. I'm sure it's economics, but when you're spending 40-50K or a lot more on a towable an extra $300 is easily buried in the overall cost. I, for one, would gladly spend the relatively little bit extra for a system that works.

For us it's actually accurate gray water levels that would be helpful. As JRTJH stated, the black water is pretty easy to keep track of.

If you look through the "why didn't those dummies at Keystone" threads in this forum, you'll find that members wish Keystone would have "spent just a little more" for things like tires, stereo, steps, decals, carpet, TV size/brand, appliances, awnings, windows, furniture upgrades, dual pane windows, air conditioner, cupboard/cabinet finish, vinyl flooring, toilet, faucets, shower doors, mattresses, door locks, window coverings, CO monitor, smoke alarms, CH751 access key sets, bumper strength, hitch receiver, improved running lights (just to name a few recent complaints).....

As you can see, if Keystone "catered to all our wishes" (including high dollar tank sensor systems) we'd all be paying much more than "just a little more" for our trailers. They'd all be "in the Allegro Bus range" (450K+)

daveinaz · 04-26-2019, 02:26 PM

We've used the aforementioned ice trick before with success. Otherwise, buy that toilet wand that attaches to hose and give it a good rinse from the toilet side.

jsb5717 · 04-26-2019, 03:19 PM

Quote:

Originally Posted by JRTJH

As you can see, if Keystone "catered to all our wishes" (including high dollar tank sensor systems) we'd all be paying much more than "just a little more" for our trailers. They'd all be "in the Allegro Bus range" (450K+)

Excellent point. I guess we buy what we can afford and live with or fix the rest. It's still a fun journey and some battles simply aren't worth the fight.

travelin texans · 04-26-2019, 08:23 PM

Buy a clear 45 or 90 degree fitting, place it on the rv sewer connection then connect your 3" hose, add ice &/or chemicals whichever makes you feel good, then pull the handles, drain/flush, once you don't see anything running through that clear fitting the tanks are empty, then close the handles & FORGET about the worthless sensors.

Froglaw · 05-01-2019, 10:39 AM

If you have an exterior Black Tank Flush, hook up and run it for 30 minutes. You have to be at a dump station or a slot with full hook ups.

I was in Valdez, AK and my neighbor had a really nice Airstream that required a big flush every few weeks.

Doesn't hurt to run fresh water through the system in order to avoid build up, smells, etc.

Cbrez · 05-01-2019, 11:44 AM

Welcome to the black tank always full club. You can fight it or go with the flow. We fought it for the first couple of years - using the Geo Method mostly - but nothing seemed to work so we are now blissfully happy going with the flow. Never had the black tank overflow. Even though we treat after every dump, the odors don’t stay below deck as it gets close to full.

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