Malfunctioning black tank valve

[DesertCat]

This is my first post on this forum - though I have been reading it for 3 years.. I went to empty my waste tanks starting with the black tank. When finished, the valve would not close and the switch indicator was on. I tried flushing the black in case something was blocking the valve from closing, to no avail. I pulled fuse #7 and replaced it without effect. When I press the black valve switch, there is no sound. I am ~1500 miles from home and no where near an airstream dealer. Does anyone have suggestions? (Where is Protagonist?)

[Lily&Me]

Hmm....someone may be able to troubleshoot this for you, but I would also look for RV repair near you.

You've looked at your owners manual for tips?

Good luck.

Maggie

[InterBlog]

Where is Protagonist... a question many have asked... the answer is not here, but some of us strive to fill his very large shoes at least occasionally.


The issue rings a faint bell with me but we have an older Interstate so we don't have that valve. I'm sure one of the NCV3 owners will chime in quickly.

[3bcamper]

Originally Posted by DesertCat

This is my first post on this forum - though I have been reading it for 3 years.. I went to empty my waste tanks starting with the black tank. When finished, the valve would not close and the switch indicator was on. I tried flushing the black in case something was blocking the valve from closing, to no avail. I pulled fuse #7 and replaced it without effect. When I press the black valve switch, there is no sound. I am ~1500 miles from home and no where near an airstream dealer. Does anyone have suggestions? (Where is Protagonist?)

Which year and model rv do you have?

[Boxster1971]

Originally Posted by DesertCat

This is my first post on this forum - though I have been reading it for 3 years.. I went to empty my waste tanks starting with the black tank. When finished, the valve would not close and the switch indicator was on. I tried flushing the black in case something was blocking the valve from closing, to no avail. I pulled fuse #7 and replaced it without effect. When I press the black valve switch, there is no sound. I am ~1500 miles from home and no where near an airstream dealer. Does anyone have suggestions? (Where is Protagonist?)

Does the Macerator pump run? ... or is it just a problem with the dump valve. The valve can be closed manually but you will have to get under the van to do it. I'm attaching a page from owner's manual on how to free up the Macerator pump and the details on the dump valves. I assume Airstream is still using the Auto-Drain valves.

Good Luck,

[DesertCat]

I have a 2015 Grand Tour. The problem seems to be limited to the black tank valve - the macerator works. Thanks everyone for help.

[73shark]

If you decide to go the manual route, might check the wiring while you are under there. I know Protag said he could only open one valve at a time but I could open both at the same time on mine. Not there was a need to do so. Not sure how AS interlocked them but you might try the gray valve just to see.

[UKDUDE]

On mine only one valve can be open at any one time.
Just a thought, but I wonder if the wires on the switches (behind the switch panel) can be swapped; perhaps that will permit the grey valve to be opened.

[Air99]

Don't know if this helps: On my 2014.5, my gray valve reopened just a bit after closing and the red indicator light turned on, like something squishy was stuck at the valve body, and a very small leak dripping at the macerator body. To force close it, I kept pressing on its close switch while opening the black valve, then quickly close the black valve, this step seemed to hold the gray valve shut and stopped the leak completely, there is an interplay between the two valves which stops one from moving while the other is in action. I would experiment with both valves alternately to see if there's a sticking sensor keeping your red valve from closing. I'll think of what next to assist you hang in there!

[Air99]

If yours are like mine, the stuck open black valve will prevent you from dumping your full gray tank and service is nowhere near, I would look for a cement sidewalk that I could drive on and put the left side of the rig up to gain access to the under belly and manually open the gray dump valve so you can dump for the remainder of your trip or next service. This makes a common tank so you need to close all the sink and bathroom drains tight after each use to prevent odor in your coach. This worries me every time I used the system, slick when it works but sucks when it fails due to complexity.

[Titus]

I have a 2013 Lounge EXT. My valves only open one at a time. Perhaps the problem is with the relay. On mine the relays are under the road-side seat, against the van wall and sitting on top of the rear wheel well. Perhaps try swapping relays (mine are identical) and see if the problem moves to the other valve.

[ASI]

the issue I had was the valve was turned so the wiring was too close to the exhaust and the valve stopped working when the wires melted and shorted out. To troubleshoot, I swapped the wiring harness at the switches. when the black valve didn't work with good wiring at the switch, I crawled under and found melted wires.

[Aircruiser]

Had the same issue a couple of times. First time I crawled under the van and disconnected the black tank valve rod from the motor and worked the valve open and closed several times until I felt it break through what I assumed was toilet paper stuck in the path of the valve. Hooked it back up and it worked fine. The second time it happened, I added a lot of water from the toilet to the tank, then opened the valve with the switch and turned on the macerator and it flushed the toilet paper from the valve and it closed as it should after that. The key I think is to make sure there is plenty of liquid in the black tank before dumping. I remember reading something somewhere about different brands of toilet paper and how well they dissolved, and the winner was not an RV specific paper, but a common brand, but I don't remember which one.

[PSchw]

I use angel soft which seams to work fine.
I try to any dump of the tanks are full and if I store for longer time I keep water in the black and gray tank do nothing can dry out and harden.

[elgo]

I don’t know if OP solved their problem but I’m having this same issue. Grey opens and closes fine. Black opens but doesn’t close. This leads me to blv it’s not a wiring issue. As a temp solution if you reach under the van where the toilet is, you will see this stem sticking out (photo attached is upside down). If you push very hard on it, you can close it manually. This at least allows you to empty out grey, and more importantly it keeps anything stuck in black valve from drying and solidifying. I am still searching for the cause in my case. There was no TP in our tank and the fact that it manually closes suggests to me the issue isn’t an obstruction. My guess is it’s not wiring as that would affect both opening AND closing Ideas and theories welcomed !

[Air99]

Originally Posted by elgo

I don’t know if OP solved their problem but I’m having this same issue. Grey opens and closes fine. Black opens but doesn’t close. This leads me to blv it’s not a wiring issue. As a temp solution if you reach under the van where the toilet is, you will see this stem sticking out (photo attached is upside down). If you push very hard on it, you can close it manually. This at least allows you to empty out grey, and more importantly it keeps anything stuck in black valve from drying and solidifying. I am still searching for the cause in my case. There was no TP in our tank and the fact that it manually closes suggests to me the issue isn’t an obstruction. My guess is it’s not wiring as that would affect both opening AND closing Ideas and theories welcomed !

Maybe the black tank switch 3-way close position is bad and not making contact?