Black Water Valve issue

[davcarv]

Hi Guys,

So I just bought a vintage Excella, 1989.

Took her out on her first camping trip and when leaving and finishing up the dumping procedure I was not able to close the clip on the black water valve.

I had a conversation with the guy I bought it from. He said that I might try,

1. Putting a gallon of Hydrochloric acid from my local Home Depot in the black water tank.
2. Filling the tank with water the rest of the way.
3. Open a close the valve several times over and over.
4. Leave the valve open for a week half way.
5. Again open and close the valve several times, repeat.
6. Dump the tank.

I respect the guys advice immensely. That being said, I am putting acid in my black water tank. But I have to imagine that there are other materials in the tank that aren’t plastic. Maybe rubber and or metal for level detection. I don’t know.

He said that he felt confident that eventually it would come unstuck and the valve will close correctly.

So, I’m posing the question(s) here.

Is this a tried and true method to, ‘Un-stick’, vintage valves?

And if it does work is this something that I should work into my winterizing and or de-winterizing process?

I’m also considering just having the valves replaced. I’ve gotten prices from both AS and an AS dealer. Although pricey it’s not so cost prohibitive if it eliminates this issue.

Thanks

Dave

[HowieE]

I have had the same issue with my 91 for several years. I think there is some material, most likely compressed paper, in the seat of the valve. To date it has only resulted in a small amount of balck water leaking into the area downstream of the valve. This means I open the cap with caution.

I would look at a replacement valve to be sure there is not any rubber involved in the seat of the valve before I would use acid. If the valve is plastic on plastic tat may be a course of action. If you do take that course you will have to just crack the valve as the tank is drained of the acid solution to be sure the blockage is subject to the acid for as long a period as possible.

Lot me know it it works.

[azflycaster]

There are two reasons why a valve will not close all the way. The most common is something is stuck in the area where the valve blade seats. This would most likely be a piece of paper. The other possibility is that the seal is shot on the valve preventing it from seating correctly.

If you can get to the valve, you can take it apart and replace the seal. Rebuild kits are not very expensive.

Pouring acid into the tank sounds dangerous to me...

[Protagonist]

Originally Posted by davcarv

1. Putting a gallon of Hydrochloric acid from my local Home Depot in the black water tank.
2. Filling the tank with water the rest of the way.
3. Open a close the valve several times over and over.
4. Leave the valve open for a week half way.
5. Again open and close the valve several times, repeat.
6. Dump the tank.

I respect the guys advice immensely. That being said, I am putting acid in my black water tank.

I can't help feeling that this is a Bad Idea™. Doing it as the guy said, by adding acid first, then diluting, you've got full-strength acid in the tank for however long it takes to get the water added. That can't be good for any metal parts, and probably not for most of the ABS plastic or rubber parts, either. Two different chemical resistance guides I consulted showed that ABS has only limited resistance to hydrchloric acid in concentrations above 10%. Another guide for rubber compounds indicates that nitrile rubber has poor resistance to hydrochloric acide; natural rubber has limited resistance, and butyl rubber has good resistance— if the acid is cold! But I don't know if the rubber in your waste system is butyle rubber or some other type. And if the acid is hot, all bets are off; it will attack all rubber compounds equally.

If you MUST try this, dilute the acid with COLD water first, THEN pour it in. But by far it would be better to choose a different solvent.

Old-fashioned glycerine (available in the first aid equipment aisle of your supermarket) makes a decent lubricant and is actually good for rubber. I haven't tried using it for unsticking a waste tank valve, though.

[dznf0g]

What about the new Rid-X product for RVs? It has enzymes which will eat the paper. I would store it with that valve open and a good tight cap. When you open...stand back.

[polarlyse]

No one has yet suggested a good backflush. I got a flush-king valve a few years ago and find it works nicely. Fits on the discharge with a gate valve. Upstream from the gate is a hose fitting. With the FK gate closed and the trailer black valve open you can backflush and put a large volume of water into the black tank quickly. I use it a couple of times a year and always when planning to store it for awhile. There might be other flush options but I feel that this one works well. Good luck with this.

[davcarv]

thanks guys, ... For clarity, ... the valve isn't stuck in the traditional sense you may think.
The plunger pulls open completely and depresses inward seemingly completely.
However, I cannot secure the metal clips because they seem to need for the plunger to be depressed a bit further giving me the impression that the gate has not closed completely. I think it's because there is some sediment or TP that's preventing proper closeure.
Make sense?

[azflycaster]

If it isn't leaking, you will know when you take the cap off, I would leave it alone. The handles on mine are adjustable.

[Pick]

I had this same problem, and I am sorry to say, I ended up replacing the valve assembly. It is not really a hard job, if the tank is been emptied. Upon inspection of the old valve after it was removed, I found I made the right decision.

[davcarv]

Thanks Richard, ... Adjustable? How so, ... like turning the T handle clockwise counter clockwise?
Thanks

[blickcd]

I had the same problem years ago. I took a a piece of garden hose about a foot long and plugged one end. I put several holes in the sides, close to that plugged end, and the opposite end had a female connection. In effect this was a flexible spray wand with jets out the side.

With the valve open, tank empty of course, I weaseled the wand up the sewer outlet and twisted it around while connected to a garden hose. I got a lot of little bits of paper and other stuff out, which improved the situation right away, but didn't completely solve the problem.

After that I tried some of that toilet tissue digester stuff. As I recall I had to do several applications before the valve seal was completely clean. The warmer it is outside, the better that enzyme seems to work.

I wouldn't put any acid down the toilet. You might end up destroying the valve, and maybe even the holding tank.

[azflycaster]

Originally Posted by davcarv

Thanks Richard, ... Adjustable? How so, ... like turning the T handle clockwise counter clockwise?
Thanks

My thetford valves have the "T" that screws into the valve shaft. There is a lock nut on the "T" that needs to be loosened to make an adjustment.

[HowieE]

Originally Posted by polarlyse

No one has yet suggested a good backflush. I got a flush-king valve a few years ago and find it works nicely. Fits on the discharge with a gate valve. Upstream from the gate is a hose fitting. With the FK gate closed and the trailer black valve open you can backflush and put a large volume of water into the black tank quickly. I use it a couple of times a year and always when planning to store it for awhile. There might be other flush options but I feel that this one works well. Good luck with this.

This is the first time I have ever heard of a reason to backflush. It sounds like a good idea.

I would suggest if you do this that you park the trailer street side High on blocks or other means. This will keep the water from coming back at you when you remove the hose. Just open the valve about a 1/4 in to insure the flow is forced past the area of the valve that most likely has the issue.

[Al and Missy]

I had the same problem until I discovered I could turn the handle clockwise and screw it in until the clips would fit. I checked my gray water valve handle and it works the same. If, as azflycaster suggests, there is a locknut on the shaft, mine must be loose. Now I have to go check and tighten it up.

Al

[Wingeezer]

As others have said, you may well be able to loosen the lock nut and screw in the tee handle a couple of turns to solve your problem. My trailer provides that adjustment, I'm nt sure if they all do.

Another possible issue might be the operating rod arrangement.

Again, I don't know if yours is set up like mine, but the operating rod going to the black tank valve has a ninety degree bend in it. Because of this, when you push the tee handle in, you are not getting a direct push on the valve operating rod and things don't work as smoothly as they might.

If the valve on mine mine is at all baulky and doesn't want to close well, I reach in behind, grab the portion of the operating rod after the ninety degree bend and push directly there as well as on the tee handle - that gets it the valve closed nice and securely.

Brian.

(PS - not sure I would be trying hydrochloric acid! But if you do, and if you want to dilute it, add acid to water, not water to acid when diluting. If you do it incorrectly the acid can spit up in your face! Safety glasses recommended in any case!)

[badkat]

I did the same thing..turned the handle to get the clips to go on..then I had seepage from the valve. Returned it to the difficult position and no seepage. Just checked ..my lock nut was loose. Hope it doesn't change our situation since we got it corrected. We do have to push hard to close the black tank. Gray is easy and works fine.

Great info!

[blkmagikca]

I've been through this as well. About 2-1/2 years ago I had JC rebuild the valve on my '87 Excella. It was rather involved, as they had to cut open part of the banana skins (which was partly replaced with new sheet aluminum). Last week I was in JC again, and this issue came up, as the knob on the black water valve had actually snapped off as it was very hard to open the valve. JC flushed the tank and it helped somewhat. The issue is that crud builds up on the blade of the valve. As well, toilet paper gets stuck in the blade seal. All this means that firstly you must use a good enzyme product that breaks down all solids including toilet paper (the one I know of is called Unique, and is sold at Ace Hardware stores - it is in their catalog so it can be ordered by the store), and secondly, flushing the tank. While I would normally use a backflush, JC used a pipe attached to a hose that sprayed the water out of a hole on the side - this was done with the valve open so anything caught in the seal would wash away. From what I gather, this is the only way to fix this issue, short of a major re-engineering of the waste system.