Black tank question

tjw0099 wrote:
We took our Jayco out for the first time this weekend.
Had a great time and some first time stories to tell.

We located the monitor that shows the level of waste in the black/grey/potable water tanks and the battery indicator.

The black tank is showing 3 of 4 lights, meaning its 3/4 full.

I looked via the toilet and it doesn't seem that full. I back washed into the black tank hoping to dislodge any blockage. The flow was fine and only moderate in 'black' evidence. We used hot water, poured down the toilet and good flush but the reading is still 3/4.

I do not have a hose connection to the black tank, just the goose neck adapter that allows me to backwash the goose neck. (At least I couldn't find a hose connection. 2006 Jayco Jayflight 25RKS.

Input appreciated.

Tom in Gloucester, Va

Tom,
The black tank monitors on your rig or any other trailer do not accurately work or at best are almost 70% inaccurate:(:(. Reasons,
1. balck tank sensors are located on the inside of the tank and "debris" both human and toliet paper do not get completly clean every time you empty the tank. Back flushing every dump will help in getting most of the debris removed. Making sure the "gray" tanks are almost full as well as the black tank also helps.
2. Most folks don't put enough water in the toilet bowl after each usage. This frequently happens when you have guests visiting who do not RV.
3. After a few RV trips you will get a fairly accurate estimate of how many days the 2 of you can use the toilet before it is close to full. I have a 45gal black, 90gal. gray and 75gal. fresh. With 2 of us, the gray will last 7 to 10 days(being conservative), I have never filled the black before needing to empty the gray.
4. Before I pull the handle to empty the black, I always put approx. 5 gal. of water using the black flush then I pull the handle but I also let the back flush run until the black water is clear. You can also just put a couple of gallons of h20 in the toilet.

They are working as designed:
1. Cheap
2. The salesman explains how you have these great monitors

If the FW sensor works OK then use it for a good estimate of tank levels by not using city water, just the pump.

It is actually pretty simple. Observe the level of the black tank through the toilet. When the water backs up into the shower, the gray tank is full.:B

The tank level indicator systems on most RVs are notoriously unreliable/inaccurate. The best method to determine the level in the black tank is to open the toilet valve and take a look. A flashlight helps, but be careful not to drop it.

Those sensors are rarely accurate after a few uses. Because of that and because I know how long it takes to actually fill the tanks, I dont even look at them unless I think they're nearly full.
BTW, 3 of 4 lights = 2/3 full. The first light is the empty indicator and lights up to show the gauge is on.

Not sure what a goose-neck adapter is....unless you are talking about a clear adapter that goes on the end of waste tank drain line and it has a hose connection that allows you to run water backup thru drain line ??


Anyway......2006 Jayco is a used trailer. Therefore the level indicators are suspect because it doesn't take much to foul the 'sensors' up. TP, dried stuff, slime, just being wet........will cause them to indicate.

You can drive yourself silly trying to keep the sensors clean and indicating correctly only to have them foul up next trip out.
Surprised only one in just black tank----usually at least 2 and grey tank also.

You can use the GEO Method (water softener/dish soap/water mixture) to clean up tank & sensors to slosh around while in transit
You can use bags of ice down toilet to scrub tank while in transit
You can purchase numerous products to clean/deodorize/sanitize/micro enzyme treat tanks
You can pour buckets of hot soapy water down toilet and repeatedly dump tanks
You can back flush gallons of water thru tanks

You can drive yourself insane.......

OR you can enjoy camping and dump rinse tanks when needed and forget about the level indicators
Toilet 'burps' when flushing-----time to dump black tank
Sink/shower drain slows down/doesn't drain as fast as normal-----time to dump grey tank
On-board water pump goes '''burrrrrrrrrup'----should have refilled fresh water tank sooner cause you have run out of fresh water

Couple of trips you will have an idea how long YOU can go before needing to dump/refill

I haven't looked at our tank level indicators in over 6 yrs. Don't care/don't need.
Same goes for that 'battery condition' indicator too.
It will always show FULL if connected to shore power and various levels when not on shore power.....but what exactly is 2 lights??

I check my batteries via hydrometer and handheld multimeter

Go camping.....enjoy and dump when tanks are full

It is my observation that because the tanks are long, wide and shallow in depth it is very difficult to get an accurate reading. Add to this the debris that coats the sensors and I find that +/- 1/3 of the tank is about as accurate as I am likely to get.

Fortunately with the Black water you can look down the hole. My Fresh water gauge seems to have less of a problem but Grey water can be concern.

I believe that most RV folks I judge from past experience. If the Gray or Black water gauge says full I dump. If not I try to estimate how full it really is. I always dump before I travel, no use carrying the extra weight.

Interesting the same problem was posted by someone else today.
The same cures probably apply in your case
http://forums.motorhomemagazine.com/index.cfm/fuseaction/thread/tid/28001363.cfm