Holding tank dump valves: Servicing & "Auto Drain" removal

[Blue~Go]

Couple of topics here, but they are both related to the dump valves, so I'm putting them together. First the Auto Drains and their removal, and then the (prophylactic) replacement of the grey and black drain valves, plus parts information.

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When I bought my rig, it had Chinook installed "Auto Drain" electrically operated dump valves for both the grey and black water holding tanks. This kind of made me chuckle, because the valves are very easy to reach (and it's not like you don't have to bend down to attach and detach the hose anyway). They also gave me that "What could possibly go wrong?!" feeling I mean, I could just picture them opening (electrically!) at some inopportune time. To top things off, the control switches were in the compartment that holds the electrical cord. (Note that this in on a 1999 rig, and I know that small changes have been made to the electrical cord compartment, plus I believe Chinook stopped using Auto Drains, although I know they were on some 2000's at least, but not sure when they stopped using them.)

This whole thing made me groan, as I would really have preferred plain old simple manual valves, like I had on my last rig (van). However when I looked more closely, I saw that they WERE just plain old manual valves. The Auto Drain was just an electrical "puller," mechanically attached to the regular manual drain stem (the only part missing was the easily obtained and installed T-handle on the stem). Hallelujah! I had envisioned something much more complicated. To start, here is what the Auto Drains look like. There is one on each valve (grey and black tank drain lines).

[Blue~Go]

Looking at the back side, you can clearly see how it is just a small motor attached to the regular old manual valve with a metal plate, and then there is a plastic "arm" that pulls the valve handle in and out. I simply removed the two fasteners that held the plate on, plus the one at the end of the arm, and... good-bye Auto Drain.

There are wires attached to each drain (they are quite obvious, although it takes a bit of care as they are in wire looms along with other wires, such as the ones that lead to the tank sensors). The two switches for the drains are on the forward wall of the compartment that holds the electrical cord (right by the compartment door). They are also easily removed (although I forgot to photograph them).

I did make one mistake though, which is that I forgot to figure out where the power was coming from before I removed them. Oops. Nothing bad happened, but it makes it harder to figure out where Chinook got the power from. I did have a friend help me test it afterward (because I wanted to disconnect the wires at the other end as well), but we were unable to figure out where the power was tapped (they were not on the Chinook added auxilliary fuse block, as I would have thought). I also thought it might have something to do with the ignition, but still wasn't sure how to find it. So at the time I just did a good job of capping off those wires.

Somewhat recently, a fellow posted a "tale" in which his Auto Drains (on a 2000 Chinook) decided to "auto" when he did not want them to (my exact fear). Along with telling the story he mentioned that the switches received power when the key was in the "Aux" position. Aha! A valuable clue (I haven't followed up on this yet, but I intend to, as I don't like to leave mysteries unsolved!)

Back to the drains themselves: Once I had the Auto Drains physically removed, it was just a matter of getting a couple of the T-handles and screwing them on. Ahhhh, back to good-old manual valves. While I was down there, I decided that after 15 years, it was probably a good time to just replace the valves (they didn't leak, but why wait, I figured). It is possible to just get new seals, but I decided to simply buy entire new valves, as they are not that expensive (I also got an extra set of seals).

[Blue~Go]

So, before removing the old valves, I wanted to have new ones on hand. I noticed that the Chinook did not have the ubiquitous Valterra valves, like my last rig. Instead, it had unkown to me "Bristol" valves. I had to do a little bit of hunting to figure out the new part numbers for valves to match (the attachment fastener pattern is slightly different than on other brands).

I now know that these are made by Bristol-Lasalle, and they are not impossible to find, although you don't tend to see them at every Wal-Mart or hardware store with an RV aisle. That's one reason I decided to just replace the whole valve, plus stock a set of replacement seals for both valves. Here is the new part info:

By the way, I had previously replaced a grey tank valve on my former rig. Before I did that, I watched a helpful video, which I'll link to here. Okay, not exactly a blockbuster, but informative. I found it really useful before tackling it the first time on my other rig - at that time I had never worked on these valves before (or owned an RV with them).

https://www.youtube.com/watch?v=UKSHnWhpMf0

[Blue~Go]

Pretty much the whole process is covered in the linked video, except for a couple of Chinook specific details. As you'll notice (at least if your drains are set up the same as those on my Concourse), the two drains lead into a central pipe that has a bayonet cover on it. That whole fore-and-aft central pipe has to be removed (plus the fastener holding a support strap in the middle) to get to the valves to replace them. You can see that here (don't worry, the tanks were empty, and the only thing in them before was a bit of water and antifreeze) (of course I still had gloves on, but I mean you don't need to be afraid to look ).

First, here is the outer section that needs to be removed:

And what is left on the rig:

The valves go in between these two pieces. I was boondocking in a gravelly area, so used plenty of cardboard and plastic etc. to keep a clean work area (the valves need to stay grit-free).

What is a little bit trickier on the Chinook is that you have to get all four seals and both valves on, plus the removed pipe section, and then the eight fasteners -- without disturbing the placement of the seals. Bit tricky with only two hands! I found that putting a bit of plumber's grease on the seals helped "stick" them in place while I got everything back together. Whew. Then I tightened the eight fasteners (turning the screws not the knurled nuts, as they show in the video) moving around the squares as I tightened so as to keep them even (i.e. not tightening any single one all the way before moving on to the others). I erred slightly on the side of "less tight" until I tested them (if you get them too tight, the handles are really hard to pull open; too loose and they leak). Then I replaced the perforated hanger strap in the center of the fixed pipe.

Subsequent testing (with plain water into the tanks) revealed a very slight leak in the grey tank valve, so I tightened it just a bit more. A small leak ends up collecting behind the bayonet cover for the main drain, but does not leak out onto the ground (until you open that cover). But of course I still wanted to make it so that neither valve leaked, so I just tightened the grey valve slightly, tested, then a bit more, until it stopped leaking completely. The valve handle is still not too hard to open/close.

No more Auto Drains, brand new valves and seals, plus a set of seals in the spares box. Ahhh.

[Manitou]

I'll just add my 2 cents in here. I replaced my dump valves today. I had a leak that was coming from the redder fitting in the grey tank (or so I thought). Removing that glued in fitting had me worried. I bought a small torch as I youtubed that heat can get glued together fittings apart (search for yourself and see.. It's kinda cool actually). I didn't end up using it though. My fitting was so loose, that I was able to just pull it out with channel locks. (Rocking it back and forth by holding the reduced part with the locks).
I can see there was some repair done at the tank port before.. I suspect it was hit. There was some tape that had long since let go around the tank insulation. After I had glued all the replacement fitting in, I went to taping it up again. This is where things got me concerned again.. I think my grey tank may have a hairline crack in it. If so.. I guess I'll be replacing the tank.. In spring... I'm fairly sure today's repairs will at least get me by till then. It wasn't leaking bad even though I could pull that reducer fitting out (supposed to have been glued in). So with new fittings, glue, valves and then foil tape holding the insulation/heating elements in place. I hope I don't see a drop for a few months.. (Or ever).

I did slather what looked like a hairline crack with glue before enclosing it in the insulation/tape.. Maybe I'll get lucky and that's that.

(I didn't take enough pics today)

[chin_k]

I cut the wires to the actuators for emergency "repair" and operate them in manual mode when I was miles away from Internet, trying to use them for the first time. It turns out both are working, just that I did not have key on the ignition. I checked the switches this evening, and they do indeed getting the power when the key is at ACC. The switch closer to the outside is for the black valve, the one further inside is for the grey one.

The fuse for the auto dump is near the emergency brake, it is lower left, labeled "Red 14G 7.5A prewired ignition hot tap" on the manual diagram.

[chin_k]

I noticed the black valve have a very small leak during the trip on the Mojave desert, and so I decided to replace it as soon as I got home so there will be no embarrassment. The gray water valve was apparently replaced before, since it is Valterra, while the black valve is original, from Bristol. Both are difficult to open and close. I decided to replace the original 3 inch valve with Valterra, since I have spare seals for them laying around in the garage (but I need to buy the valve body, but they are relatively cheap, for less than $20), and the rest of the plumbing are all Valterra already.

I removed the black valve by itself, and noticed that leak is due to the blade/paddle pushed the seal out of place. The bolts on the bottom are also rusted, and I actually managed to break one of the bolts when I tried to loosen it. At the end, I decided to take the entire "combiner" piece off, and check the gray valve and make it easier to clean the surface before attachment. I end up replaced the seal on the gray valve because it was attached incorrectly, but still hold water. I washed the gray valve to get the grits and sand out, and put some silicon grease on the metal shaft, and it is moving much easier.

To install the whole assembly back, I used silicon grease to get the seals to stick to the fittings, and put the valve body in between, then attach the bolts. I attached the gray side first, and purposely not tighten the bolts so there are some wiggle room for the black valve. After the black valve is attached, I then tighten up all the bolts slightly. I tested the valves, and they seem to be working great, and easily open/close. I added a plastic handle to the gray valve, and so now both the black and gray valves are manual.

[terriv]

Time to tackle this project. I've been looking at this cobbled up mess since I bought the camper last fall.
What is the proper way to tie off these old Auto Drain wires?
Never done this before and I want to get it right. How far back do I go & what type fittings/terminals do I use?
Thanks for your tips & help.

[chin_k]

If you are not going to use the wires, can't you just pull them out into the electrical area so that there is nothing dangling around?

[terriv]

Good idea.

BUT the 3" side blk & red wires are enclosed in split black wire tubing & head up & into the nether regions- never to be seen again.
The 1.5" side blk wire goes to frame rail & red wire is just draped forward & over various undercarriage parts then up & lost behind drivers door area.

Thanks to this post I did find & remove the "prewired hot tap fuse."
I found where the switch WAS installed. I found just two empty mounting holes & these cut wires (see pic).

So, I'm just going to cut the two set of wires as far back as I can reach & be done with it!