Black Tank Sensors

[shineman54]

2006 Destination. Black tank lights show tank is always 2/3 full. Was going to change out sensors but after disassembling water bay seen there were 3 black squares on each tank. Only 5 inches between tanks to work with. Need to know how these sensors work. Thanks

[Morich]

We had a post and discussion a while back and the poster found info on how they worked but it is such a space age level thing that I knew that I would never be able to measure the tiny voltage levels they speak of, so forgot about needing that info! not just a simple battery and ground type thing but things that very few of us would be able to test or measure.
Basic answer seemed to be that there are two different boards in the monitor panel, one red, one green and one type is known to be a failure problem-----if I remember correctly. But that memory is a big question, so I will take a look at old posts and see if I can find it as better than my memory!
EDIT:
Found the post that I think might be of help:
https://www.winnieowners.com/forums/...rd-359216.html

Down about post four gives the specs he got and some info on how they work? ASSUMING they are the same for you? Danger in assuming, though!!!

[creativepart]

Generally, the problem with these is "debris" on the side of the tank inside. The best way to fix this is a power clean. There are some that do this as a service. But it's pretty nasty.

There are a number of businesses near you in Phoenix that do this service:

https://tanktechsrx.com/
https://hydrocleanaz.com/
https://allprowaterflow.com/

[Wyatt]

Originally Posted by shineman54

2006 Destination. Black tank lights show tank is always 2/3 full. Was going to change out sensors but after disassembling water bay seen there were 3 black squares on each tank. Only 5 inches between tanks to work with. Need to know how these sensors work. Thanks

What type of sensors do you have? I’ve replaced mine, but not sure if we have the same type of set up.

[Oldchinahand]

I'm with creativepart on this one. Likely solids inside the tank fouling the sensors.

We've had this problem arise on longer trips. Once we poured 1/2 bottle fabric softener down the toilet and drove to our next stop. Worked.

Once we put up with it until we got home. We flushed the tank until the water ran clean. (Using internal flushing system) Then filled the tank until we could see water through the toilet flush ball. Then poured a full bottle of enzymes - RidX - and let it set for a week. The little beasties munched away. Worked.

Hopefully, those efforts will continue to work. Not looking fwd to hydroblasting.

Fair Winds and Following Seas

[Wyatt]

Originally Posted by Oldchinahand

I'm with creativepart on this one. Likely solids inside the tank fouling the sensors.

We've had this problem arise on longer trips. Once we poured 1/2 bottle fabric softener down the toilet and drove to our next stop. Worked.

Once we put up with it until we got home. We flushed the tank until the water ran clean. (Using internal flushing system) Then filled the tank until we could see water through the toilet flush ball. Then poured a full bottle of enzymes - RidX - and let it set for a week. The little beasties munched away. Worked.

Hopefully, those efforts will continue to work. Not looking fwd to hydroblasting.

Fair Winds and Following Seas

Flushing the tanks properly is a very important maintenance issue to stay on top of. When we return from a trip, a do a thorough cleaning, but on the road, we don’t always have the ability do do as good of a job. And alas, my sensors used to read partially dull when drained—both gray and black tanks—rendering the gauges rather worthless.

That’s why I switched the wholly inadequate OEM probes (not really probes at all, but simply a bolt in a rubber gasket that is prone to debris failure).

The probe swap out took about two hours, mainly because the black tank was nearly inaccessible. They cost about $60.00. If your tanks uses these, I would highly recommend them. Two sets, one for gray tank and one for the black...

[imnprsd]

My 2004 Itasca Horizon (40AD) holding tank sensors for the Black Water and Gray Water have not worked for as long as I have owned this coach; and I'm guessing they did not work that great back in 2004 either.

I have not yet fixed mine, but I would like to this season. So I did some research and found some information that suggests their may be a ground problem at the circuit board the drives the led status lights.

* Some people have also elected to upgrade to a "Red Board" to fix this problem, but there are indications you can fix your old circuit board if you know what to do. (TBD. Remember I have not confirmed any of this.)

* Most people just replace the sensors, but I don't think everyone is happy with different types of sensors out there. I.e., this is a buyer-beware problem.

This fix I will share with you, but I think it may only apply to certain Winnebago's. That said, I don't know if your vintage RV uses the same system? Heck, I don't even know if I have that same system applicable to a "Red Board" fix/upgrade?

Maybe someone else knows more about this? ...When I look at the size of this "Red Board" I can't believe it it located behind the holding tank display in the picture below, but I have never taken that area apart. Does this PC Board even apply to my RV?

My research suggest some owners have had success making repairs to the circuit board (to ground and minor repairs); whereas other owners ordered a so-called "Red Board" as described below. ...But this topic has not been discussed for over 10 years that I know of. Maybe that's about the time a company started making "Red Board" replacement upgrades and the art of repairing these thing fell in the a crack?

* Remember, I can not confirm or deny this information will work. What I do know is that this is a different approach vs. installing an aftermarket holding tank sensor kit. But again, I think this fix is mostly targeting Winnebago owners unless you have the same display panel as me?

Holding Tank Sensor Repair Notes (A Work In Progress)

I came across a thread on the Winnebago Forum website that talks about a fix for the holding tank fuel gauge problem so common in RVs.

https://www.winnieowners.com/forums/...rd-359216.html

This lead me to a service bulletin Winnebago put out years ago and which I have never seen:

https://winnebagoind.com/resources/s...ue%20Level.pdf

Alternatively, most people seem to use aftermarket upgrades and replace the sensors in each tank, but this suggestion by Winnebago suggests replacing the circuit board and fixing a ground problem is another way to go.

Personally, I think if I were going to attempt this repair, I would:

A) First try fixing the ground at the old circuit board I have now; and if that did not fix the problem...

B) I would take my circuit board to a local TV repair shop and let him probe around for a diode problem.

C) I have tried calling Winnebago to get a price on this True Line Circuit Board #133004-05-701, but have not been able to get through. However, I found it may be made by Ventline...

Electronics – Ventline L5130-02 PC Board for Monitor Panel – Red Offers | RV Parts And Accessories

...And while it use to be available on Amazon it is currently not being sold at this time. ...But here is the Amazon link:

https://www.amazon.com/Ventline-L513...SIN=B00ODJ5RRU

[thompwil]

The square stick-on sensors are similar to capacitive proximity sensors. I’ve used similar technology in industrial applications. Industrial sensors have sensitivity adjustments that could account for any material coating on the inside of the tank. Our sensors do not adjust so I decreased the sensitivity by carefully removing the sensor, cleaning off all the factory adhesive, then applying two layers of 3-M double stick tape to the entire surface, then mount back into place. This decreases the capacitive coupling while still sensing the actual levels in the tank. It works much better now, I consider it 80% fixed, but it will still hang up if we get too much greasy stuff down the drain, we avoid doing that but it still happens occasionally. I plan to add another layer of 3-M tape in the spring to see if that corrects it completely.

[golden13]

Originally Posted by shineman54

2006 Destination. Black tank lights show tank is always 2/3 full. Was going to change out sensors but after disassembling water bay seen there were 3 black squares on each tank. Only 5 inches between tanks to work with. Need to know how these sensors work. Thanks

I wouldn't bother with it. Every Black tank I've ever worked with gets the sensors fouled with sludge and TP in a very short period of time, and never quite gets unfouled.

I've used a water-macerator, my rig has a tank flush valve that causes a ball to bounce around inside the tank, and I have a wand that uses a rotating spray to put down the commode. I also use fabric softener and enzyme pods. There's an extra chemical that did help a bit more called "Thetford Tank Blaster." It's another enzyme deal that seemed to help a bit.

Bottom line, your tank can be empty and your sensors will still read "full" because of the sludge. I found it best to just clean and empty it as per normal, and not worry about the gauge lights. It's obvious when it's empty enough, because the commode doesn't smell bad. We've spent HOURS flushing those tanks and to NO avail.

I don't believe that replacing the sensors would do you any lasting good. It's just a terrible design for an unpleasant problem.

[Morich]

Originally Posted by golden13

I wouldn't bother with it. Every Black tank I've ever worked with gets the sensors fouled with sludge and TP in a very short period of time, and never quite gets unfouled.

I've used a water-macerator, my rig has a tank flush valve that causes a ball to bounce around inside the tank, and I have a wand that uses a rotating spray to put down the commode. I also use fabric softener and enzyme pods. There's an extra chemical that did help a bit more called "Thetford Tank Blaster." It's another enzyme deal that seemed to help a bit.

Bottom line, your tank can be empty and your sensors will still read "full" because of the sludge. I found it best to just clean and empty it as per normal, and not worry about the gauge lights. It's obvious when it's empty enough, because the commode doesn't smell bad. We've spent HOURS flushing those tanks and to NO avail.

I don't believe that replacing the sensors would do you any lasting good. It's just a terrible design for an unpleasant problem.

You don't mention what age or what RV you have so there is no way to check but it is certainly true that the newer sensors are not like the old and they do work much better. It sounds like you have some that are more than ten years old, so likely to be the older style which foul so easy from any type of debris inside.
It is certainly true that electronics have changed a good deal in the last 10-20 years so if you have the old style, they can be a real problem.

[Wyatt]

Originally Posted by golden13

I wouldn't bother with it. Every Black tank I've ever worked with gets the sensors fouled with sludge and TP in a very short period of time, and never quite gets unfouled....

I don't believe that replacing the sensors would do you any lasting good. It's just a terrible design for an unpleasant problem.

I'm more optimistic. See the two black (1.5 year old) OEM sensors I removed from our tank and the reason why they are fraught with a design issue? Note the sludge imbedded into the Gray tank sensors. That's why they're always showing a reading above empty--they're clogged up with gunk.

Compare that OEM design to the Horst probes and it's easy to see why that's a much improved system.

[imnprsd]

I really like it when every system in my RV is working "right!"

However, I also know when my gray water needs changing, because my shower pan fills up over the P-trap. This use to be disgusting, but after many flushes and degreasing of the gray water tank... "it's not soo bad any more."

Note: Nothing cuts the grease in these tanks. I have tried everything -- and adding water softeners to the tank just makes them smell (black tank especially) worse.

However, now that they sell 5X Dawn Power Wash on the market, I'm going to clean my gray water tank one more time to see if this does the trick. ...And frankly, I expect great results.

This Dawn 5x stuff is a new formulation of high alkaline cleaners that really foams up and I believe it will work best if I follow these steps:

* Add 1 bottle of Dawn 5x Power Wash to the gray tank only.

* Add ~5 gallons of water to the tank... and go for a 10 minute drive to slosh it all around.

Note: The goal it to clean the sensors more than the tank itself.

* The Dawn will really foam up. ...Then I would let it sit over night.

* The next day I would add 5 more gallons of water and go for a drive again.

* Return and rinse twice.

* Then fill the tank 50% and drive around again.

* Return and rinse one last time... Then fill the tank 100% and drain right after.

* Then test your level indicators by filling the tank up and see if your gauges work?

Note: Your black tank has good bacteria in it. So you do NOT want to use harsh cleaners. Instead, I found I can add 1 cup of "BORAX" powder to the tank after every black water tank flush to help reduce odor. (And Boraxo is not very expensive!)

Note: I tried Odoban, but with mixed success.

The Borax will help keep the anaerobic bacteria from blooming... and that will reduce the smell. And always use those RV toilet products with the Boraxo.

...Again, do not clean your black tank with anything other than a fresh water rinse several times every month... if your are camping for long periods of time.

IF I HAVE TO GO TO AN AFTERMART TANK SENSOR KIT ==> Do those external tank sending units or strips work better than Miracle Probes?

[plrude]

There is a product on amazon that uses microbes to clean your tanks. Both of my tanks were not working in the 2005 leisure van I bought. I filled the tanks with water and the microbes and let sit for two weeks. My gauges now work but the microbes work so well cleaning gunk, that my sewage valves started leaking and had to be replaced. When I dump, I have to pull an attached sewer hose out which left black slime on my gloves. After the treatment, my sewer hose was spotless with no slime. The product is Caravan sewage treatment.

[js167h]

I believe the build up on the black tank interior walls is referred to as struvite which is pretty unavoidable with regular use. Stick on sensors definitely are effected by this. Walex offers some great products for tank maintenance and rehab. Their commando product works great for removing struvite. Apply 2 of the commando pouches to your black tank and fill to 3/4. Let sit for 2 weeks and the struvite will be broken down. You will see lots of black scale drain out of the tank if you use a clear hose adapter. Apply one Walex elemonate to your grey tank after emptying if you don’t have full hook ups. It does a great job cutting through grease and dairy maintaining sensor health. Our coach is 9 years old now which sees an average of 40 nights use during the summer months with no full hook ups and both black tanks and grey work flawlessly.

[imnprsd]

So... no one has ever heard of those so called "Red Boards" ...to fix your OEM tank monitoring system?

I think the point here is that your OEM sensors are working, but your OEM circuit board is not able to produce accurate readings.

In my system (see pictures above), my fresh water tank sensor work, and my grey and black tank sensor (LEDs) still light up, but bounce around between "Empty" and 1/4 Tank. ...Every once in a while the gray tank will register "Full" but I know it's empty.

So on one hand those probes can be upgraded and this is what most people do.

Question: When you install a Miracle Probe, do you still use your OEM (Led) light-gauge; or do you get a different display?

OR...

Is there any chance this "Red Board" upgrade will allow you to use your OEM probes "as-is" so you do not need to replace them?

And if using a "Red Board" upgrade works, then what year models need the Red Board? (Pre-2008 for example??? IDK.) I'm just asking what this "Red Board" is all about, because its use, form-fit-function, seems to have fallen in the cracks over time. (Aka Dinosaur Board.)

[Wyatt]

Originally Posted by imnprsd

So... no one has ever heard of those so called "Red Boards" ...to fix your OEM tank monitoring system?

Question: When you install a Miracle Probe, do you still use your OEM (Led) light-gauge; or do you get a different display?

OR...

Is there any chance this "Red Board" upgrade will allow you to use your OEM probes "as-is" so you do not need to replace them?

IDK, I think the reason there are varying types of sensors, and circuit boards that support them, and that’s why were getting varying responses.

I can answer one of your questions. When I removed the OEM “sensors”, and installed the Horst Miracle probes, they worked with the OEM display panel seamlessly. That might not be true, if different tanks sensors use different technology.

[tim myers]

This is an old thread, but I have similar issues. My 2007 Journey uses the exterior probes (no contact style). I have went through many efforts to clean the tanks, both black and grey. The readings will be all screwy and then all of a sudden they appear to be normal. I also have issues with the Fresh Water Tank, which shouldn't have all the issues with the inside of the tank like the black and grey do. I have also read about the read about the green vs red control boards and will open up the monitor center in the next couple weeks to see which board I have.

[creativepart]

Tim, have you reset your Oneplace monitor?

To reset the One Place system hold down the "pump", "tank" and "battery" buttons (all 3 at the same time) for 10 or so seconds. The version number will display. Then press the "battery" button to reactivate.

It may not do anything but it's worth a try.

PS. You might have more luck with a new post rather than posting on a 2-year old thread. Let me know if you want me to fix this for you.

[tim myers]

I don't have the one place monitor panel.

[creativepart]

Originally Posted by tim myers

I don't have the one place monitor panel.

Oh... I thought that went way back in the 2000's. Sorry.