Faulty Black Water Sensor

[richie t]

Just got back from a two week camping trip and my black water tank is still reading 3/4 full. Emptied it at 3/4 at the campground. When I got home I flushed it out with the tank flush and it was still reading 3/4. Would you try flushing it out from the top at the toilet? Thanks.

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[Grumpy]

Nothing new with factory sensors.

[Murff]

My black water tank has been 2/3rds full for a couple of years!



Murff

[spoon059]

What they are trying to say is that this is a pretty common issue with tank sensors. They stick out into the black tank to measure resistance, which allows them to suggest approximate water levels. A piece of toilet paper (or something worse!!!) stuck on a sensor will give a false reading.

My suggestion (take it for what its worth...) is to place a couple or 10 gallons of water in the black tank and put some toilet chemical down there. Drive home from the campground and let that water and chemical slosh around. Drive back to the next campground with that water still in there and let it slosh around some more.

Following this theory (and that is all that it is...) I have been able to keep my sensors relatively accurate for 2.5 years now.

[howlin4you]

Originally Posted by richie t

Would you try flushing it out from the top at the toilet?

Yes. I've recently had the same problem and flushed the tank from the top for a few minutes. Problem solved. Pick up one of these and give it a shot - https://www.etrailer.com/RV-Plumbing/Camco/CAM40074.html

[norty1]

I gave up on worrying about the factory sensors. They will always be a source of lost time for you unless you want to spend big bucks and get a better system like Sea level or something else. After camping a while, the tank levels can be anticipated without even using the indictor as they are never dependable.

Exception is the fresh water tank indicator and it is nothing but water. Even at that only 1/4, 1/2, and 3/4 does not tell me much with the size tank we have.

[sennister]

As others mentioned they are more trouble than they are worth at times. We have yet to come close to filling our Grey tank so I don't pay attention to that the one too much. We rarely if ever take showers so the only thing going in there is a little bit of use from one of the three sinks. I would say we use the outdoor shower a 50 times for every one use of the inside one. I worry about the most is the black and you can see how full that is when flushing. If there is any tank I watch the gauge on it is the fresh water. Before leaving, more often than not I am running a lot of fresh water in the sink to build up more Grey to clean the dump hose out and stuff.

[Bassdogs]

Originally Posted by richie t

Just got back from a two week camping trip and my black water tank is still reading 3/4 full. Emptied it at 3/4 at the campground. When I got home I flushed it out with the tank flush and it was still reading 3/4. Would you try flushing it out from the top at the toilet? Thanks.

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As has been noted and repeated a thousand times, the OEM tank sensors are JUNK!! Nothing you do will make them other than JUNK!

[JFlightRisk]

Originally Posted by richie t

Just got back from a two week camping trip and my black water tank is still reading 3/4 full. Emptied it at 3/4 at the campground. When I got home I flushed it out with the tank flush and it was still reading 3/4. Would you try flushing it out from the top at the toilet? Thanks.

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We always flush the tank with a wand down the toilet when we're at a full hook up site. DW watches the clear elbow outside while I give the tank a good rinsing. She knocks on the side of the TT when it's running clear. The level gauge will say 1/3 full for about 10 minutes, then go out. Just something we do, and the TT is 5 years old this year.

[dgodecke]

My service manager suggested Tide Detergent to clean the tank and sensors. One full bottle of Tide Original (not the HE stuff), let it slosh around while you drive and then rinse and put in the normal chemicals you use. Works for me.

[saintsfan]

I also use a spray wand after dumping. Just a bit of advise about the wand: make sure the toilet cover is partially closed before you open the valve on the hose to avoid a back spray from coming up from the tank/toilet. Looking forward to the next TT having the built in sprayers to clean/flush the tank. hope they work as advertised.

[wags999]

I used the black tank flush each time I dump, and my sensors read perfectly. If your only dumping and not flushing than the sensors most likely will not operate properly. It's amazing what I can get out of my tank even after 4 or 5 minutes of flushing.

[oldmanAZ]

Originally Posted by wags999

I used the black tank flush each time I dump, and my sensors read perfectly. If your only dumping and not flushing than the sensors most likely will not operate properly. It's amazing what I can get out of my tank even after 4 or 5 minutes of flushing.

We have the same trailer. And we, too, use the black tank flush every time we dump, but our black tank gauge ALWAYS reads 3/4full. I have a clear section sewer and can see that the flush gets out lots of 'stuff', but even if the water from the tank is running clear the gauge still says 3/4full.

Please let me know if you use chemicals (I haven't) or some other device or fill & dump procedure or ???

I'm ok with the gauge not reading right, but if there's a way to get it reading correctly, I'd really like to try it.

[wags999]

Originally Posted by oldmanAZ

We have the same trailer. And we, too, use the black tank flush every time we dump, but our black tank gauge ALWAYS reads 3/4full. I have a clear section sewer and can see that the flush gets out lots of 'stuff', but even if the water from the tank is running clear the gauge still says 3/4full.

Please let me know if you use chemicals (I haven't) or some other device or fill & dump procedure or ???

I'm ok with the gauge not reading right, but if there's a way to get it reading correctly, I'd really like to try it.

Google the GEO method...it's a good way to really clean your tank. I turn the flush on and than open the tank. After it empties I will close the tank and allow the water to fill a little bit...than drain it again. Not every dump but when I feel it's needed. I've no issues with the sensors not reading empty after doing this. I do keep 5 - 10 gallons in the tank when were traveling which does help clean any remaining residue. Perhaps I've been lucky


We also use regular Kirkland TP, since were hooked up to water we flush a little more often than I may normally do, but it's a non issue since we have unlimited water to flush with. If I was boon docking or not at a full hook up site I would use the RV paper, it's thinner and does break down quicker. As to chemicals I really don't use any here. It's cool at night and as I said I flush about every 5 days or do. No problem with odors. We do use plenty of water with each flush also. I think that is the key, more water less issues.

Good Luck.

[Atlee]

I'm not too concerned about mine. For one thing, I've never filled my black to near over flow position before, usually not even close. And if I were getting close, I should be able to see it down the comode.

If it gets to where I can see it, it definitely time to dump.

I just assume they will not be accurate after the first time I fill the black tank.

[oldmanAZ]

Originally Posted by wags999

Google the GEO method...it's a good way to really clean your tank. I turn the flush on and than open the tank. After it empties I will close the tank and allow the water to fill a little bit...than drain it again. Not every dump but when I feel it's needed. I've no issues with the sensors not reading empty after doing this. I do keep 5 - 10 gallons in the tank when were traveling which does help clean any remaining residue. Perhaps I've been lucky


We also use regular Kirkland TP, since were hooked up to water we flush a little more often than I may normally do, but it's a non issue since we have unlimited water to flush with. If I was boon docking or not at a full hook up site I would use the RV paper, it's thinner and does break down quicker. As to chemicals I really don't use any here. It's cool at night and as I said I flush about every 5 days or do. No problem with odors. We do use plenty of water with each flush also. I think that is the key, more water less issues.

Good Luck.

Thanks, Waggs.
Well it seems we do virtually the same as you (same dumping process, plenty of water, no chemicals, water in the tank after dumping). We do use Scott single ply, not Kirkland, but Scott breaks down readily so I'm sure that's not it.

To flush, we a 'brown' hose to bypass our filters and regulator to use full flow and pressure from our site's water supply. Maybe it is just the difference in where our tank flushes happen to spray.

Since day 1, we have had Calgon (and Rid-X) in the trailer. We wash dishes with Dawn dish soap, so we (that really means 'me' ) might try the 'Calgon and Dawn GEO method' in the black tank the next time we go camping and see what happens.

[ttavasc]

Originally Posted by oldmanAZ

Thanks, Waggs.
Well it seems we do virtually the same as you (same dumping process, plenty of water, no chemicals, water in the tank after dumping). We do use Scott single ply, not Kirkland, but Scott breaks down readily so I'm sure that's not it.

To flush, we a 'brown' hose to bypass our filters and regulator to use full flow and pressure from our site's water supply. Maybe it is just the difference in where our tank flushes happen to spray.

Since day 1, we have had Calgon (and Rid-X) in the trailer. We wash dishes with Dawn dish soap, so we (that really means 'me' ) might try the 'Calgon and Dawn GEO method' in the black tank the next time we go camping and see what happens.

I use the fabric softener/Dawn mixture in both the black and gray tanks whenever they are obviously out of whack and it seems to get them back to working as expected fairly quickly. Our tanks are fairly small so I use 1/2 cup of the fabric softener and 1/4 cup of regular Dawn per tank. Maybe double that for larger tanks.