Where does black tank overflow go?

[Capt Bravo]

Originally Posted by EngineerMike

I use the TLAR method

I would stay with "That Looks about Right"! As long as you do not see "goo" running down the sides of your Motor Home, than "That Looks about Right" applies. One could say "TFAR" (That Feels about Right"), but one would need to be in touch with their inner self to get that "feeling". In my case, "TSAR" (That Sounds about Right) applied as I could hear the water being forced up the vent pipe. I can't remember which I did first, shut off the water or open the valve, but disaster was averted.

2005 WRV 36 MDDS
2004 Suzuki Grand Vitara

[wa8yxm]

Water dripping from the A/C intake grill is often a sign of dirty intake filters. among other things.

Where does black tank overflow go? One of two (or 3) places.

1: All over the bathroom floor (Stinky mess)

2: Down inside the walls where the vent pipe runs up to the roof (even bigger mess)

3: Out the vent (Robin Williams method) Very rare.

Something to think about.

On many motor homes the vent pipe is like 1.5" in diamater, it rests inside a rubber or plastic vent about 3" in diamater, big gap between the "Stack" pipe and the roof vent, so it can easily run down INSIDE the walls making one mel of a hess if it does not cover the bathroom floor.

Thankfully, Mine does the bathroom floor.

[RinkersRanch]

Originally Posted by codgerbill

I might be mistaken, but on some coaches the vent tube that goes to the roof has a shared connection with the black and grey tank. The connections are approx. 2/3rds or more of the way up the stack. The resultant overflow will flow up the stack and into the grey tank and then come out of the shower drain. A friend of mine has a Pace Arrow and he was not paying attention when flushing out the black tank. His wife was "screaming" as the green stuff flowed out of the shower drain onto the coaches floor

Yep, my Pace has a 'T' in the vent for the grey tank. When I first got my, very used, Pace, the smell was real bad in the drain compartment. I did a lot of reading about a 'Geo' method of tank maintenance and hooked to the sewer line clean out plug in the front yard and started flushing the Black tank. A neighbor came by to see why the RV was parked in the front yard and to look at my, new to me, RV. Yep, it was at this time I found that the black tank and the grey tank are connected. When I got the oops I had been filling (flushing) the black tank too long feeling I shut off the water, ran inside and found the inside the RV nice and dry. I thought I really messed up. Wondering where all that water went, I checked the tank levels, and the previously dry grey tank was 1/2 full. The black tank was filled up to the bottom of the toilet valve but did not overflow when I opened the valve. So I am very fortunate that Fleetwood put a 'T' in the vent line. By the way the vent pipe 'T' connection on mine is below the bottom of the toilet. I am sorry to have to admit that I have since been distracted by the 'shiny things' and found that when flushing the black tank too much for the grey tank to hold the overflow, the bathtub will fill. God must have known how forgetful I am and made sure I got this model RV.

Oh, by the way, the Geo method did a great job of clearing up the stinky drain compartment. I now need to build one of those, under the coach, 'stinky slinky' holding tubes. After a couple months storage I need to air out that compartment for a while. During our summer use there is no smell at all.

[Old Trucker]

Originally Posted by gator67

When I flush my black tank, I close it, then fill the tank. It usually takes 12-15 minutes. I have it set so when the full light on the gauge comes on, I go out and open the valve. This has always worked. I have a regulator on the filler hose. This morning, the full light was on solid after 10 minutes. I ran out and opened the valve and looked for overflow but didn't see anything.

A little later, water started dripping form my A/C intake grill in the living room. Now, I cannot imagine how the two are related, but it was awfully coincidental. We've had rain here a few days ago and ther was no leak. The A/C wasn't running, so I know it wasn't defrosting.

So, that begged the question... if there IS an overflow in the black tank, where does it go?

Hi Gator, sounds likeyou got a lot of advise on the problem.. I had a 99 and can testify that there is not an overflow, but if overfilled the water runs out the vent on the roof. Maybe the A/C gasket is weak and allowed water around the grill inside.

Washing the black tank; Why fill the tank?? You have a sewer wash option. I hook my optional hose on the sewer wash and use a sprayer nozel with threads on the end of the sprayer to connect to the coach wash and leave the valve OPEN. The owners manuel also tells you to leave the valve open. This seems to provide more pressure and never had any problems.

My wife flushed the toilet one day, then held the flush valve up to allow more water in the bowl. She was not aware that the valve had stuck, but a few hours later we had the mess cleaned up.... good wishes, old trucker

[Renipladlo]

Dave I am with you!!!

There is no overflow drain on the Black Tank, they powers that be don't want crap all over the place/road/driveway or in the rv park except for the sewer period.

When the gauge says full, there is still a tiny bit of room maybe a couple of gallons which could still be put into the tank, we never fill our black tank, we go to within 5-10 gallons of full, and then dump it. We flush it each and every time we empty it, and a day or two before dump day, I close the gray tank to then have some gray water in the tank to flush the hose out so particulate matter does not sit in that hose, it's also good to "cycle the valves" to keep them limbered up some. There is a tank valve lubricant you can purchase, you pour in a half of a cup or so, before you season the tank before first use, since it is heaver than the fluid in the tank it goes to the valve and sits there and would be the first thing dumped.