Black Tank Filling Mysteriously

[QuiGonJohn]

2006 Winnebago Aspect 26A.  Came home from a weeklong trip on 4/28.  We dumped the morning we left and used the toilet a very little bit on the drive home.  Been in the RV doing some projects, (vacuuming, put in a stereo, etc,), have not used the bathroom.  NOT connected to city water and the water pump has been off.  Periodically I check levels, just as a practice when I am in the RV, it had been reading empty (just green light at the bottom).  Yesterday I checked and the Black Tank was flashing RED for the full light.  Today it was solid RED and I opened the valve and shined a flashlight into the tank and it does appear to be nearly full.  Not sure how this can be.  I don't think anyone has gone in there and filled the tank.  We keep the RV locked, parked on the side of our house.  I had thought the sensors were just whacked, but not since visually looking at the level.  Don't know what else it could be.  I think the way they systems are plumbed, even if the water pump were on, unless the toilet valve was ON or leaking, I don't think there is any other connection that allows water to the Black Tank.

Anyone ever heard of a similar problem?  Any ideas?

[blakeloke]

Are your grey water and black water dump valves connected into a common drain for your sewer hose?  The tanks could equalize if the valves are open or leaking by.  Have you used sink or shower water to clean whilst on the road home or while at home?

Blake

[QuiGonJohn]

They do share a common drain.  But both valves are shut.  We have used a little water to clean and such, but nowhere near the 30+ gals the black and grey tanks hold (Black 32 & Grey 37).  I also took the drain cover plate off and no water leaking out, it was pretty dry in between the 2 dump valves and I reached in and felt the dump valves and they seem shut correctly.  If the dump valves were leaking I would expect there should have been some water pooled there.

[wolfe10]

Are you sure that the black tank IS that full.  The sensors are notoriously inaccurate and fluid level in there may be difficult to determine. 

I agree with you-- can't see a source for water to get in there.  There is no direct connection potable or gray to black.

 

[kaypsmith]

Do you have a honey wagon "portable storage tank"? If so, I would drain the black tank into it to find out how much is actually in it. Tissue lodging on the sensor inside the tank is the most common cause for sensors reporting incorrectly. The only other place that water could enter is through the roof vent, and that's very unlikely unless you have a mischeivious neighbor.

[desertdeals69]

I would dump the tank again and make sure the tank is totally empty and then monitor it again.

[wildebill308]

All good suggestions to a puzzling problem. Here is a big a** guess. Is it possible that while you had the waterpump on the water valve on the commode was leaking. Letting the water run into the black tank? I had one leak internally and fill the black tank. It wasn't a lot but it added up. Querious minds want to know.

Bill

[QuiGonJohn]

Well when I looked in the tank today, no water connected, water pump off.  It looked like I could see the water level I'd say about 4" below the bottom of the whole assembly where the toilet attaches to the floor and into the tank.  I am nearly 100 certain that no plumbing goes to the tank, only to feed the flow to the toilet valve.  Mine is foot operated and does not seem to be leaking.  Also the level in the toilet bowl did not go up which I would expect if the valve to flush was leaking.  Our is the kind you press a little to get water flowing and press a little further to open the valve to actually empty the toilet.

My thought was possibly rain into the vent tube.  But the cap/cover on the vent tube seems to be fine, (I went on the roof to check that).

[kaypsmith]

If the tank is directly below the commode, you can open the flush flapper and use a stick to actually check the water level. I would still prefer the honey wagon approach. As you said if the valve on the commode was leaking, I think that there would be an overflow onto the floor.

[QuiGonJohn]

So an update.  Maybe it is the sensors being wonky.  I went to check again, now the lights only show 2/3 flickering.  Full is out, 1/3 & Empty are both lit.  I looked into the tank, from the toilet, but instead of just looking I took a long stick and lowered it into the tank.  From this, it seems that only about 1 to 2 inches of tank have liquid and above that, anywhere from 4 to 6 inches or so, there is not water.  I was worried it might start overflowing, just sitting there.  I feel a little better now.   I will monitor it daily until I pull the RV out for our next trip, the first weekend in June.  Wow kps, I just did this before reading your post.  No honeywagon here to try that with.

 

[wolfe10]

Agree, wonky sensors absolutely the most likely cause of your worry.

If you place you can dump black water (most homes on city sewer have a large clean-out point between home and main line) you could use a bucket to drain what is in there.  If, as we suspect, you have a sensor problem, not fluid level problem, a couple of buckets is all you will get. 

[wildebill308]

It does sound like the typical sensors. Remember you won't see any water leaking with the pump off. It is still a good practise to shut the pump off when not in the coach/storage.

Bill

[kaypsmith]

The best tank sensor cleaner that I have used is 1/2 cup Calgon  water softener (Walmart or any box store usually around washing detergents), 1/4 cup dawn dish soap, 3/4 tank fresh water, take a nice drive, then empty.

[desertdeals69]

I got tired of fooling with the tank sensors so I went with See Level external sensors.

[QuiGonJohn]

kps, I do the Calgon water softener method.  When I first bought this RV the sensors gave me all sorts of weird readings. After doing that method it has been good until now. Funny thing is when I dumped and the first 2 weeks parked at home, it always showed empty.  I'm wondering if some animal (lizard) maybe somehow got in there splashing around to get the sensors wet.  Otherwise not sure why it would have suddenly been giving me this high reading. Wolfe, might try the buckets, now that I am pretty sure there is not much in there.

[Lenp]

Not sure how your Winnebago is plumed but mine (and many others) has one (of two) bathroom sinks connected to the black tank.  Winnebago wisdom says you need LOTS of water in the black tank. And they make sure of it!

Once you have dumped both gray and black tanks get yourself a clear elbow and attach it to the dump outlet.  Then open just the black valve and turn on water in each of your sinks and showers (one at a time) and see if any of them are draining into your black tank.  Mine has a sink in the "hallway" that drains into the black tank.  The sink in the stool room, shower and kitchen all drain to the gray tank.

Lenp

[manholt]

I had a 07 WB 40 foot, it had a sink in the bedroom (why?) and the water went into the black tank...found out by reading the owners manual, so I shut off the water to sink!  On my current rig, I use the same as Kay, but still get a red light on toilet when it's 1/4 full, then have to flush from outside and light goes off.  60 gal, tank!  Don't ever get a electric toilet !  Red light=no flush!  Green=flush!

Carl

[QuiGonJohn]

Well I just looked in my Operator's Manual and Operator's Manual Supplement and cannot tell if the bathroom (hallway) sink drains to grey or black.  But the parts breakdown of my model does make it seem like it drains to the grey.  They show that sink separate, near the top, then down by the pic of the black tank (which is closer to that sink), they show a line, with a p-trap and that line goes to the grey tank.  Next time I am connected to sewage I will test by putting the water on full at that sink and looking into the black tank.  If it is draining there I should be able to tell by doing that.  I believe the sink (21) gets is attched to the line at the p-trap (14) that is directly over the black tank, and that line (13) goes to the grey tank in this diagram.

 

[hermanmullins]

Am I missing something. I thought it was found to be a faulty sensor and that the toiler was not mysteriously filling by itself.

However that's a nice diagram.

Herman 

[QuiGonJohn]

I was just getting back to leenp & manholt's comments.  FYI, this morning the indicator is red again.  I'm baffled.  This is an RV sitting locked up on the side of my house.

[hermanmullins]

Herman

[jleamont]

Last coach neither tank gave good readings, I installed these, they worked great! And were simple to install.

http://www.rvprobes.com/home.html

 

[five]

This coach and our previous coach, both ACs, have used the SensaTank Level Monitoring System.  It's the only system that has worked for us.  Don't know if this is the exact one, but it will get you in the area:  http://www.levelguardproducts.com/marine-rv/rv-multi-tank-monitor.php

[tbutler]

We've been using a water softener for three years now and mysteriously our sensors are working again! 

Don't bad-mouth electric toilets.  Our Thetford Aria Deluxe II is now almost 14 years old with only a couple of visits to the toilet doctor.  Works great, very durable.  We go almost 2 weeks on a 40 gallon black water tank.  If you have a problem with an electric, name it.

[jleamont]

14 hours ago, FIVE said:

This coach and our previous coach, both ACs, have used the SensaTank Level Monitoring System.  It's the only system that has worked for us.  Don't know if this is the exact one, but it will get you in the area:  http://www.levelguardproducts.com/marine-rv/rv-multi-tank-monitor.php

We have the same in our coach, works great. So far we have not had a false reading.