Pages

Friday, August 4, 2023

HOW I GOT MY BLACK TANK SENSORS TO READ ACCURATELY

The infamous black tank sensors on the Roadtrek are well known for never reading accurately. I found this out soon after I bought my 2011 190 Popular new. I even brought it back to the Roadtrek dealer's service department to have them "fixed" and the RT service tech replaced two of them - which involved leaving the old bottom two sensors in place as he said they cannot come out and installing two others next to the originals and moving the wires from the old ones to the new ones. This worked for about a day and then the same things as before started to happen.  When the black tank was empty the monitor panel would read that it was 2/3 full. Then with just a little water added to the black tank the monitor panel would read full.  During a single day the monitor panel would change - from 2/3 to full and back to 2/.3 without anything being added to the tank or taken out of the tank. They just did not work!  I should add all of the other water sensors did work accurately on my Roadtrek - the two fresh water tanks and the grey tank have always been accurate. 

I tried all the things recommended to make them work. I flushed the tank repeatedly with clean water - still the same. I used various tank additives including borax and detergent and commercial tank cleaners that say they also clean sensors -  no difference. I bought a tank wand that attaches to a garden hose that is connected to an outdoor spigot - all brought into the RT through an open door, The wand goes down into the tank - this was a flexible wand (they are not all flexible) because the black tank is not straight down the toilet drain into the black tank pipe. There is an on/off valve on the wand to shut off and turn on the water flow - which is coming out at some pressure.  You open the toilet flap and keep your foot on the pedal as if the flap shuts on the wand the flap breaks. You put the wand down into the drain and move it around and up and down to "pressure" wash the inside of the black tank.  And if you happen to move it up too high from the hole in the toilet the water from the nozzle splashed on your face.  This, too, did not work. 

I eventually gave up as many Roadtrek owners do and on a trip we counted how many days it took us to fill the black tank with average use. It came down to between four and five days which was enough for us to know that once you get to four days dump the tanks. If the days are hot summer days just before it needed to be dumped it was possible to get a small whiff of odor when flushing the toilet when the flap opened.  I also found that if you look down the open flap in the toilet with a flashlight when the tank is really full you can see the water coming up from the tank just below the toilet flap. The problem with this is it is too easy to drop the flashlight down into the black tank which is a lot more trouble than just having a full black tank. (I never did this - I put a flashlight on a cord that fit around my wrist.) I have never put a bag of crushed ice into the black tank and drove around. Big RVs say this works BUT if your Roadtrek has a macerator and do this and you are not sure if all of the ice has melted completely - and you try to dump with ice still coming out into the macerator - you will break the macerator.

Sometimes things happen accidentally - and this article is about one of those happenings. I have not written about this until now because I wanted to be sure it worked. This goes back to May 2019 and started in November of 2018. 

In November 2018 we started winterizing the Roadtrek - using the instructions of my own article - which has become well known.  It is always important to keep the black tank's interior wet and I have always put one gallon of water into the black tank during travel season to prevent anything left in the tank from drying out and building up which will clog the output of the black tank. When we started winterizing I knew that since our last trip at the end of October there was one gallon of water in the black tank. We started by getting all of the water out of the fresh tanks and then started to dump the black tank of that one gallon of water.  We got a bucket and pointed the macerator hose in - and pushed the macerator button and we could hear the macerator running and there was a spurt from the hose and then nothing. The motor ran - the macerator was not pumping. We tried various things - change the angle the RT was sitting on - nope. Tried turning the macerator unclog handle - it turned with no resistance - nope. And then we smelled burning coming from the macerator and just gave up.  It was November. There was no way we were going to get to any RV shop that could fix this and we just would have to wait until the Spring.  But what to do about the black tank until then.  When I winterize I replace the one gallon of water in the black tank to keep it wet with one gallon of RV antifreeze poured down into the tank through the toilet. I decided that in addition to the winterizing RV antifreeze that went through the pipes to the toilet I would add TWO gallons of RV antifreeze into the black tank for the winter - keeping my fingers crossed that in the Spring there would be no problems from the cold winter other than needing to get the macerator replaced. 

The Roadtrek sat on our driveway like that the entire winter and in late April 2019 we had an appointment at the RV dealer we bought the RT in that is located in Pennsylvania - two states away - for the macerator to be replaced. (There is an article about that in April and May 2019 on this site.)

An amazing thing happened when the service shop installed the new macerator and dumped the black tank of the two gallons of RV antifreeze. THE BLACK TANK READ EMPTY!  

I figured that this was only temporary and with use the black tank sensors would go back to their  old tricks and do what they were so well known to do.  We took a trip that July - the black tanks were empty at the start of the trip. The black tank holds ten gallons.  With a  day plus  of  use the monitor panel showed 1/3 full -  right on what it should be. A day or so more and it went to 2/3. As I said earlier in this article - we calculated that we fill the black tank in four to five days.  At the end of the fourth day the black tank went to full. One way to find out if the black tank is really full is to put some water down the toilet as look in the pipe -  a little water should in the pipe that the black tank was really full!  The sensors worked. We dumped the tanks and they showed empty. Even with the gallon of clean water put down into the tank the sensors still showed empty - as they should! 

I have been putting one gallon of RV antifreeze down into the black tank over the winter and until we dewinterize in the Spring  and this never fixed the sensors.  Could it be that the two gallons made the difference?  This stayed from November into late April. I did not jump to conclusions. The variables from it working and prior - the RV antifreeze and the new macerator. Others have replaced their macerator and still have black tank sensors that do not read accurately.  The two plus gallons of RV Antifreeze into the black tank over about six months, I believe, is what has done it!

After the summer of 2019 Covid arrived, so travel was limited to not at all.  We live in an area that was very hard hit by the virus.  We were on lock down. There were a lot of deaths. Businesses were closed and supermarkets that were open had empty shelves.  But I still had to winterize the RT and in 2019 I put two gallons of RV antifreeze again into the black tank in addition to the antifreeze that went down into the tank winterizing. The empty black tank showed empty when before the antifreeze went in and just the two gallons of RV A/F, it still showed empty. As Covid lessened we took some day trips using the black tank. The sensors read correctly.  After dumping it showed empty - every time!

Recently we used the black tank a lot. It went to 1/3 and correctly after that to 2/3.  Before I dumped the tank I added water to the tank and took it to full - and it read full.  We dumped the tank - and it now reads empty. I tested this over three years plus - each time winterizing two gallons of RV antifreeze went into the tank between winterizing in the late Fall and dewinterizing in the Spring. The sensors are still reading accurately. 

 So what do you do if you want the same results? I do not know that if you vary the time period shorter that the RV antifreeze is in the tank, it will work for you. If you put it in and let is sit for a couple of weeks or even a month or two, I doubt it will work!  Put it in over six months and you should have the same results. No guarantees - but if it worked for me - it should work for you. Do I use any "special" antifreeze? No - unless you consider $3.99 a gallon antifreeze from Walmart special.  This same antifreeze has kept my plumbing safe over the winter for years. Will it work with other RV antifreeze? It should.  

 For eight bucks for a fix?! It is well worth the investment in two bottles of RV antifreeze and no more guessing if the tank is full! I feel I should put steps to this of what to do. OK - 

1) When winterizing - dump your black and grey tanks before you start along with draining your fresh tanks - all part of my winterizing step by step article. This article is found at

The infamous black tank sensors on the Roadtrek are well known for never reading accurately. I found this out soon after I bought my 2011 190 Popular new. I even brought it back to the Roadtrek dealer's service department to have them "fixed" and the RT service tech replaced two of them - which involved leaving the old bottom two sensors in place as he said they cannot come out and installing two others next to the originals and moving the wires from the old ones to the new ones. This worked for about a day and then the same things as before started to happen.  When the black tank was empty the monitor panel would read that it was 2/3 full. Then with just a little water added to the black tank the monitor panel would read full.  During a single day the monitor panel would change - from 2/3 to full and back to 2/.3 without anything being added to the tank or taken out of the tank. They just did not work!  I should add all of the other water sensors did work accurately on my Roadtrek - the two fresh water tanks and the grey tank have always been accurate. 

I tried all the things recommended to make them work. I flushed the tank repeatedly with clean water - still the same. I used various tank additives including borax and detergent and commercial tank cleaners that say they also clean sensors -  no difference. I bought a tank wand that attaches to a garden hose that is connected to an outdoor spigot - all brought into the RT through an open door, The wand goes down into the tank - this was a flexible wand (they are not all flexible) because the black tank is not straight down the toilet drain into the black tank pipe. There is an on/off valve on the wand to shut off and turn on the water flow - which is coming out at some pressure.  You open the toilet flap and keep your foot on the pedal as if the flap shuts on the wand the flap breaks. You put the wand down into the drain and move it around and up and down to "pressure" wash the inside of the black tank.  And if you happen to move it up too high from the hole in the toilet the water from the nozzle splashed on your face.  This, too, did not work. 

I eventually gave up as many Roadtrek owners do and on a trip we counted how many days it took us to fill the black tank with average use. It came down to between four and five days which was enough for us to know that once you get to four days dump the tanks. If the days are hot summer days just before it needed to be dumped it was possible to get a small whiff of odor when flushing the toilet when the flap opened.  I also found that if you look down the open flap in the toilet with a flashlight when the tank is really full you can see the water coming up from the tank just below the toilet flap. The problem with this is it is too easy to drop the flashlight down into the black tank which is a lot more trouble than just having a full black tank. (I never did this - I put a flashlight on a cord that fit around my wrist.) I have never put a bag of crushed ice into the black tank and drove around. Big RVs say this works BUT if your Roadtrek has a macerator and do this and you are not sure if all of the ice has melted completely - and you try to dump with ice still coming out into the macerator - you will break the macerator.

Sometimes things happen accidentally - and this article is about one of those happenings. I have not written about this until now because I wanted to be sure it worked. This goes back to May 2019 and started in November of 2018. 

In November 2018 we started winterizing the Roadtrek - using the instructions of my own article - which has become well known.  It is always important to keep the black tank's interior wet and I have always put one gallon of water into the black tank during travel season to prevent anything left in the tank from drying out and building up which will clog the output of the black tank. When we started winterizing I knew that since our last trip at the end of October there was one gallon of water in the black tank. We started by getting all of the water out of the fresh tanks and then started to dump the black tank of that one gallon of water.  We got a bucket and pointed the macerator hose in - and pushed the macerator button and we could hear the macerator running and there was a spurt from the hose and then nothing. The motor ran - the macerator was not pumping. We tried various things - change the angle the RT was sitting on - nope. Tried turning the macerator unclog handle - it turned with no resistance - nope. And then we smelled burning coming from the macerator and just gave up.  It was November. There was no way we were going to get to any RV shop that could fix this and we just would have to wait until the Spring.  But what to do about the black tank until then.  When I winterize I replace the one gallon of water in the black tank to keep it wet with one gallon of RV antifreeze poured down into the tank through the toilet. I decided that in addition to the winterizing RV antifreeze that went through the pipes to the toilet I would add TWO gallons of RV antifreeze into the black tank for the winter - keeping my fingers crossed that in the Spring there would be no problems from the cold winter other than needing to get the macerator replaced. 

The Roadtrek sat on our driveway like that the entire winter and in late April 2019 we had an appointment at the RV dealer we bought the RT in that is located in Pennsylvania - two states away - for the macerator to be replaced. (There is an article about that in April and May 2019 on this site.)

An amazing thing happened when the service shop installed the new macerator and dumped the black tank of the two gallons of RV antifreeze. THE BLACK TANK READ EMPTY!  

I figured that this was only temporary and with use the black tank sensors would go back to their  old tricks and do what they were so well known to do.  We took a trip that July - the black tanks were empty at the start of the trip. The black tank holds ten gallons.  With a  day plus  of  use the monitor panel showed 1/3 full -  right on what it should be. A day or so more and it went to 2/3. As I said earlier in this article - we calculated that we fill the black tank in four to five days.  At the end of the fourth day the black tank went to full. One way to find out if the black tank is really full is to put some water down the toilet as look in the pipe -  a little water should in the pipe that the black tank was really full!  The sensors worked. We dumped the tanks and they showed empty. Even with the gallon of clean water put down into the tank the sensors still showed empty - as they should! 

I have been putting one gallon of RV antifreeze down into the black tank over the winter and until we dewinterize in the Spring  and this never fixed the sensors.  Could it be that the two gallons made the difference?  This stayed from November into late April. I did not jump to conclusions. The variables from it working and prior - the RV antifreeze and the new macerator. Others have replaced their macerator and still have black tank sensors that do not read accurately.  The two plus gallons of RV Antifreeze into the black tank over about six months, I believe, is what has done it!

After the summer of 2019 Covid arrived, so travel was limited to not at all.  We live in an area that was very hard hit by the virus.  We were on lock down. There were a lot of deaths. Businesses were closed and supermarkets that were open had empty shelves.  But I still had to winterize the RT and in 2019 I put two gallons of RV antifreeze again into the black tank in addition to the antifreeze that went down into the tank winterizing. The empty black tank showed empty when before the antifreeze went in and just the two gallons of RV A/F, it still showed empty. As Covid lessened we took some day trips using the black tank. The sensors read correctly.  After dumping it showed empty - every time!

Recently we used the black tank a lot. It went to 1/3 and correctly after that to 2/3.  Before I dumped the tank I added water to the tank and took it to full - and it read full.  We dumped the tank - and it now reads empty. I tested this over three years plus - each time winterizing two gallons of RV antifreeze went into the tank between winterizing in the late Fall and dewinterizing in the Spring. The sensors are still reading accurately. 

 So what do you do if you want the same results? I do not know that if you vary the time period shorter that the RV antifreeze is in the tank, it will work for you. If you put it in and let is sit for a couple of weeks or even a month or two, I doubt it will work!  Put it in over six months and you should have the same results. No guarantees - but if it worked for me - it should work for you. Do I use any "special" antifreeze? No - unless you consider $3.99 a gallon antifreeze from Walmart special.  This same antifreeze has kept my plumbing safe over the winter for years. Will it work with other RV antifreeze? It should.  

 For eight bucks for a fix?! It is well worth the investment in two bottles of RV antifreeze and no more guessing if the tank is full! I feel I should put steps to this of what to do. OK - 

1) When winterizing - dump your black and grey tanks before you start along with draining your fresh tanks - all part of my winterizing step by step article.  This article is found here - https://roadtrek190popular.blogspot.com/2013/11/winterizing-your-roadtrek-step-by-step.html

2) Go through all the steps in the winterizing article through NUMBER 48. Instead of putting one gallon in as specified there put TWO GALLONS IN! Do this with or without a macerator. The macerator has nothing to do with fixing the sensors!

3) If you have no problem with your grey tank - as I  don't - then do not put any into the grey tank. If you want to, you certainly can but unless your sensors don't read accurately in your grey tank there is no need to do this. 

4) That is it! Leave it in until you de-winterize. While it is in the first time you do this you will still see sensors that are not working correctly. Once you dump your black tank in the Spring it should read EMPTY!