Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > MOTORHOME FORUMS > Class A Motorhome Discussions
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
Thread Tools Search this Thread Display Modes
Old 10-29-2012, 02:25 PM   #1
Join Date: Feb 2010
Posts: 60
Black Water Sensor

I have a cc magna with the silverleaf total coach control. The black water shows to be 50% on the tank capacity, but that is not correct. I have washed, flushed and backwashed but it still shows this reading. I am sure the tank is clean. It has a backwash port on it and I even built a pressure washing wand and inserted it through the head and washed thoroughly with soap and water. The sensors are on the outside of the tank and they are all still glued on and wired. I did all the above and then filled it half to three forths full , added laundry soap and drove it about 200 miles (without using the facilities) then dumped , washed etc. and it's still reading the same. Has anyone had this before and how did you fix it?
augar boy is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free! RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 10-29-2012, 02:30 PM   #2
Senior Member
trackman's Avatar
Join Date: Oct 2011
Posts: 1,136
No matter how much we clean and flush,the sensors usually give out false readings. Could be buildup that you cannot reach or just a bad sensor. You will have to gauge your use and empty periodicaly. I knew mine was empty so I kept up with the gauge and found a medium level to go by
trackman is offline   Reply With Quote
Old 10-29-2012, 04:25 PM   #3
Senior Member
Join Date: Feb 2012
Location: Baton Rouge, LA
Posts: 1,202
Fill the black tank abot 1/3 full, pour in a bag of ice cubes, then drive the coach around for an hour or so. The ice cubes will clean the gunk off the sensors, after you drain the tank, the reading should be correct unless you have a bad sensor.
Jim and Lynda, (Sophie, Jake, attack trained killer Shi-Tzus :-))

2003 Fleetwood Expedition 38N 2005 Saturn Vue
jlfbatonrg is offline   Reply With Quote
Old 10-29-2012, 04:45 PM   #4
Senior Member
szy's Avatar
Newmar Owners Club
Freightliner Owners Club
Join Date: Jul 2012
Posts: 231
Originally Posted by jlfbatonrg View Post
Fill the black tank abot 1/3 full, pour in a bag of ice cubes, then drive the coach around for an hour or so. The ice cubes will clean the gunk off the sensors, after you drain the tank, the reading should be correct unless you have a bad sensor.
this except I add Pine Sol- the whole quart jug and it really cleans the walls of the tank some say Dawn but I use PineSol with good results .
2011 Newmar Ventana with COMFORT DRIVE
2011 Jeep Wrangler with Blue Ox tow bars Roadmaster attachments
Charter Lifetime Member Good Sam Club FMCA/KOA/ Newmar Kountry Klub
szy is offline   Reply With Quote
Old 10-29-2012, 04:56 PM   #5
Senior Member
justaroamer's Avatar
Join Date: Oct 2009
Location: Lake OZ,MO summer-RiverBend Motorcoach Resort,FL winter
Posts: 686
Simple fix without the washing, etc. but do keep your tank clean.
Model 709 SeeLeveL II
available many places other than above and they use external sensor rather than internal...fixed my problem in a 1 hour install, very simple. Plus you can have a panel inside and in your drainage bay/area.
♫ Happy Trails... to You ♪....., Until We Meet Again ♪..... ♫
justaroamer is offline   Reply With Quote
Old 10-29-2012, 04:56 PM   #6
Senior Member
jzick's Avatar
Join Date: Feb 2007
Location: Florida
Posts: 1,193
Ice will work most times, Pinesol or Dawn or dishwasher soap work most of the time. Laundry detergent with Calgon wetter is my favorite. The fact is, however, that sooner or later, most of the time sooner, the sensors will get fouled again and not show the right level. Most of us who travel a lot ignore the sensors and use our ears for the sound of a nearly full tank, or look inside with a flashlight. Some spend the money and use external sensors that work much better.

If you do a search of the forum, you will see a lot of questions on this same subject. Unfortunately, there is no real good answer to your question.
jzick is offline   Reply With Quote
Old 10-30-2012, 09:57 AM   #7
Junior Member
Workhorse Chassis Owner
Join Date: Apr 2011
Location: West Linn, Oregon
Posts: 2
My fresh water and black sensors are incorrect. I just talked to my RV mechanic of 35 years and he said to put 2 talbespoons of salt or baking soda in the fresh water tank. Put much more in the toilet, sink drains and shower drain. Then, drive around for awhile. He said the electrodes on the sending units get corroded. Salt seem to work best. I'm going to try it on mine today.
vince665 is offline   Reply With Quote
Old 10-30-2012, 01:02 PM   #8
Senior Member
Barbaraok's Avatar
Alpine Owners Club
Join Date: Sep 2005
Location: Traveling in North America
Posts: 2,248
Or do what most of us do and learn what the 'burp' means - that's when you dump. It really should only take a week or two for anyone to learn your usage pattern and when it will be time to dump. Or you can spend a lot of time and money worrying about it.

Barbara & David O'Keeffe
Figment II (Alpine 2002 36 MDDS)
On The Road since 2006
Barbaraok is offline   Reply With Quote
Old 10-30-2012, 01:09 PM   #9
Moderator Emeritus
TXiceman's Avatar
Ford Super Duty Owner
Join Date: Aug 2000
Location: Bryan, TX when not traveling.
Posts: 22,409
Blog Entries: 21
You take 20 or 30 gallons of water and dump a bag or tow of ice, you had better do your driving pretty quickly as the ice will melt pretty quickly and all you are doing is sloshing wcold water. One other issue with the ice and getting the tank too cold...most of the plastics used in waste tanks getss pretty brittle when more ice may not be the answer.

Waste tank sensor do not work as they use the cheapest technology possible. The manufacturers could upgrade a bit and get sometihng that will work...but the accountants say that it is good enough to get them out of warranty and they look at the bottom line.

Amateur Radio Operator (KE5DFR)|Full-Time! - 2012 6.7L Ford Crew Cab Dually -2013 HitchHiker Champagne 38RLRSB - Currently FOR SALE Travel with one Standard Schnauzer and one small Timneh African Gray Parrot, retired mechanical engineer
TXiceman is offline   Reply With Quote
Old 10-30-2012, 05:08 PM   #10
Join Date: Feb 2010
Posts: 60
I have cleaned the inside by filling half way and adding plenty of soap, tried again with pinesoil and did it a third time with tide washing liquid. Drove 200 miles with the latter, flushed good with fresh water several times and still shows 50%. The sensors are external. Maybe a bad sensor.
augar boy is offline   Reply With Quote
Old 10-30-2012, 05:58 PM   #11
Senior Member
Luckiest Dreamer's Avatar
Winnebago Owners Club
Join Date: Jun 2010
Location: Iowa
Posts: 1,189
Did you say the sensors were on the outside? Mine are and I got bad readings as well. Even when it was new. Took it back to the factory and they determined the sensors were located in the wrong spot.
Larry B, Luckiest Dreamer
Luckiest Dreamer is offline   Reply With Quote
Old 10-30-2012, 06:11 PM   #12
Senior Member
Clayobx's Avatar
Fleetwood Owners Club
Join Date: Dec 2011
Location: Willow Lakes RV & Golf Resort, FL
Posts: 3,163
Never ending story for us all. Most likely a bad sensor since it is external! No matter internal almost never work. We have a new coach and the black side only works intermittently despite using every trick mentioned above. Live with it. You will learn when the tank is approx. half to two thirds. Just keep plenty of water flushed ALL the time. Use a good enzyme.
Clay & Pebble
2012 Providence 42 M. Spartan Chassis, 450 ISL
Ford Edge toad, RM All Terrane, TST TPMS, SMI Air Force One, RVM95....
Clayobx is offline   Reply With Quote
Old 10-31-2012, 03:06 PM   #13
Join Date: Feb 2010
Posts: 60
Yes the sensors are on the outside. I know it is not a big issue as we know just about how long to go before we need to dump. However it works some of the time showing O % but when it does malfunction it affects the control panel. It will show a problem and the amber lights come on and the green led lights blink constantly giving the silverleaf a false indication that something is wrong. I guess I need to change the sensor or just overlook it.
augar boy is offline   Reply With Quote


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

» Featured Campgrounds

Reviews provided by

All times are GMT -6. The time now is 12:45 AM.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2023, vBulletin Solutions, Inc.