Black tank level/sensors

[psw757]

Anyone have any issues with blank tank gauges or not completely dumping?

Mine is showing full all the time and I always dump with several days of liquid in it 2/3 full. I notice when dumping it doesn't seem to dump with the same velocity as the grey tank.

On our last trip I ran tank flush sprayers for an hour and still shows full.

Any ideas here? I used ice cubes etc.... no luck.

[BandJCarm]

"Shows full" probably because the sensors get wet. Let them dry and it probably (??) might go down. Mine is showing 2/3 right now and I haven't used it in 2 weeks, and I'm guessing it has about 2 gallons in it.

Drains slow......yeah, I hate that. But it's more 'solid' than the gray, so..............

[psw757]

Originally Posted by BandJCarm

"Shows full" probably because the sensors get wet. Let them dry and it probably (??) might go down. Mine is showing 2/3 right now and I haven't used it in 2 weeks, and I'm guessing it has about 2 gallons in it.

Drains slow......yeah, I hate that. But it's more 'solid' than the gray, so..............

Don't think it is wet sensors as it was emptied and sat parked in storage for a month and still showed full when we got it out to hit the road.

[5picker]

Don't rely too heavily on the accuracy of the sensors.

In ALL the R/V forums I've frequented over the years, this topic of concern is likely at the top. The factory sensors are worthless and only installed so the manufacturers can say there is 'some' kind of monitoring system.

Are there better products on the market? Sure but they cost a few bucks and manufacturers aren't going to spend the money.

As for the tank not dumping correctly... I've read more than one post saying the tank cut-out plug (for the sewer pipe connection) had dropped into the tank on assembly and then migrated itself across the drain hole. Maybe something like this has occurred on yours? Have you tried snaking the sewer line to see if there is any sort of blockage?

[billpherigo]

I had the same problem. Turned out the tank sensor was shorting against the steel bracket that holds up the driver side end of the black tank. I noticed this while I had the drivers side water bay white board removed for another project. The fix was to add a few layers of duct tape over the end of the metal bracket where the wire was shorting against it. I bet that it would be possible to just remove the 4 screws attaching the white board to the coach, and lowering the board down a few inches, to gain access to the short locations, else you will have to reach behind the panel and unscrew all of the hoses leading to the back of the panel. It is not as bad as it seems. Use a mirror to make sure you find them all.

Bill

[SilverArrowPro]

I've cleared mine in the past by adding ridex then filling the tank and let sit for as long as you can ( couple days to a week). Then dump. Paper builds up on the sensors.

[psw757]

Originally Posted by billpherigo

I had the same problem. Turned out the tank sensor was shorting against the steel bracket that holds up the driver side end of the black tank. I noticed this while I had the drivers side water bay white board removed for another project. The fix was to add a few layers of duct tape over the end of the metal bracket where the wire was shorting against it. I bet that it would be possible to just remove the 4 screws attaching the white board to the coach, and lowering the board down a few inches, to gain access to the short locations, else you will have to reach behind the panel and unscrew all of the hoses leading to the back of the panel. It is not as bad as it seems. Use a mirror to make sure you find them all.

Bill

Do you have a picture of where you applied the tape and how did you determine a wire was shorting? Was there damage to the insulation?

I am going to take a look at this today, heading to Disney in a week and would like to get this working correctly.

Thanks

[psw757]

Well doesn't appear to be wires. I took that all apart and they are in good shape and not contacting any of the supporting brackets or any other metals in the wet bay.

Is there a chemical/enzyme treatment that is most effective at digesting/liquefying waste and tissue?

We have been using mainly the dissolvable tst packets but have read good things about the thetford chemdri

[BamaBob]

Originally Posted by psw757

Well doesn't appear to be wires. I took that all apart and they are in good shape and not contacting any of the supporting brackets or any other metals in the wet bay.

Is there a chemical/enzyme treatment that is most effective at digesting/liquefying waste and tissue?

We have been using mainly the dissolvable tst packets but have read good things about the thetford chemdri

Ever since we switched to SEA-Zyme our black tank is more accurate. The enzyme really breaks down the TP - and this is what usually gets on your sensors giving you inaccurate level readings.

We get ours from Gary & Linda - fellow FROGS & FROG rally vendors:

gnlrvspecialties.com

Having said that, the only sure cure for tank accuracy would be to switch to a external monitor - most who do switch to a seelevel system.

https://www.garnetinstruments.com/rv-shop/

[BamaBob]

Originally Posted by psw757

On our last trip I ran tank flush sprayers for an hour and still shows full.

How are you using your black tank flush? A lot of folks are under the misapprehension that you hook up the water to the tank flush, open the valve and run the flush for X minutes.

This will not give you a very good result. Running a tank flush is a art form of sorts because what you need to do is CLOSE the valve and let the tank flush spray head fill your tank.

This is where the 'art' comes in -you need to have a VERY good idea of how fast your tank flush will fill your tank. Until you do, I would never run a black tank flush more than 5 min!

After a while you will get it down to a fairly precise science. For example, I know that at 50PSI it takes roughly 11 min to fill our black tank

Fill & dump your tank 2 or so times should clean most of the stuff out. If you read my previous post about SEA-Zyme, and start using that you will find it almost unnecessary to rinse out your black tank once the bacteria/enzyme colony is established. We dump every 2 weeks and those little creatures darn near liquefy everything in our black tank by the time we dump!

[510Rick]

Had to dump at a place with no water a few times and the tank got a little cruddy .So last time out I drove up to the mountains with a tank full of ice and simple green . Worked great . btw....THEY ALL DO IT

[billpherigo]

Originally Posted by psw757

Do you have a picture of where you applied the tape and how did you determine a wire was shorting? Was there damage to the insulation?

I am going to take a look at this today, heading to Disney in a week and would like to get this working correctly.

Thanks

Sorry for the late reply. The metal bracket that supports the end of the black tank was shorting to the screw on the end of the sensor where the sensor enters the tank, which is also where the wire attaches to the sensor. Seems that the tank was free to slide on the bracket about 1/4 inch forward and backward, and in some positions, it would contact the screw.

Bill

[888casper]

Paper can get hung up on the sensor. I found that using a flower watering wand with adjustable head just fits through the drain hole in the toilet. You can get it in the tank and spray all directions to clear/clean the tank up well.

[andymil]

What he said (BamaBob). I've been filling and dumping with fresh water this summer and my sensors have been staying clean. Also using 20 MT Borax with a little liquid laundry detergent once in a while. The SEA-Zyme sounds like good stuff too but I never tried it.

Be very careful and don't get distracted when filling the black tank. I installed an audible alert to let me know when the tank is full. My tank takes almost 20 minutes to fill at home (45 to 60 psi well water).

[BamaBob]

Originally Posted by andymil

What he said (BamaBob). I've been filling and dumping with fresh water this summer and my sensors have been staying clean. Also using 20 MT Borax with a little liquid laundry detergent once in a while. The SEA-Zyme sounds like good stuff too but I never tried it.



Be very careful and don't get distracted when filling the black tank. I installed an audible alert to let me know when the tank is full. My tank takes almost 20 minutes to fill at home (45 to 60 psi well water).

Please tell me about your audible alarm! I have been using the countdown timer on my iPhone, a sensor alarm however would be completely foolproof at any water pressure!

[andymil]

Originally Posted by BamaBob

Please tell me about your audible alarm!

I got a sensor (eBay) that I stuck to the side of the tank with double sided tape. I connected the sensor to a 12 volt LED with a Piezzo beeper built in (Amazon). I ran a separate 12 volt wire and a ground wire to the frame.

I'll look up the parts and try to post links. The sensor came from China so it takes a couple of weeks.

[andymil]

22mm 12V DC Red LED Flashing Buzzer Pilot Panel Indicator Light

https://www.amazon.com/Flashing-Buzz...FJZCB0Z77ZDP3K


3M Scotch 4011 Exterior Mounting Tape, 1 in x 60 in

https://www.amazon.com/3M-Scotch-401...TCH0ZAWGBM7KJE


12-24V Non-contact Tank Liquid Water Level Detect Sensor Switch Container D9P9

12-24V Non-contact Tank Liquid Water Level Detect Sensor Switch Container D9P9 | eBay

I'm not sure about foolproof but I'll use this along with the timer. I can't vouch for the reliability. Time will tell. I mounted the indicator in the outside shower box so I can see and hear it when flush is on.

I used one sensor for half full (LED only) and one near the top of the tank. I did the same on the gray tank. These are completely separate from the OEM level indicators. If nothing else, I have a better understanding what's actually in the tank when a level indicator is lit.

[Scrapper]

Originally Posted by andymil

22mm 12V DC Red LED Flashing Buzzer Pilot Panel Indicator Light

https://www.amazon.com/Flashing-Buzz...FJZCB0Z77ZDP3K


3M Scotch 4011 Exterior Mounting Tape, 1 in x 60 in

https://www.amazon.com/3M-Scotch-401...TCH0ZAWGBM7KJE


12-24V Non-contact Tank Liquid Water Level Detect Sensor Switch Container D9P9

12-24V Non-contact Tank Liquid Water Level Detect Sensor Switch Container D9P9 | eBay

I'm not sure about foolproof but I'll use this along with the timer. I can't vouch for the reliability. Time will tell. I mounted the indicator in the outside shower box so I can see and hear it when flush is on.

I used one sensor for half full (LED only) and one near the top of the tank. I did the same on the gray tank. These are completely separate from the OEM level indicators. If nothing else, I have a better understanding what's actually in the tank when a level indicator is lit.

That looks like it would be a good project if you can get to the tanks, unfortunately my tanks are fully enclosed in the underbelly.

[andymil]

Originally Posted by Scrapper

That looks like it would be a good project if you can get to the tanks, unfortunately my tanks are fully enclosed in the underbelly.

Mine are too. I was able to get at the end of the tanks by removing the patches they put around the pipes where they exit the underbelly.

That reminds me, I need to get a can of foam.