Remote dump valves in RVs, a good idea poorly designed and executed

For the lucky of us who are not concerned with using our RVs in below freezing temperatures, we do not have to worry about the dump valves on our tanks freezing in the winter. Unfortunately, the unlucky among us who live in their RVs year round or use their RVs and work in cold climes do.

Now there are a couple of ways to keep dump valves from freezing. One is to heat them with pads that have wires buried in them and are heated with electricity. Very few RVs used this method, although some manufacturers use pads to keep the tanks from freezing. I will note here parenthetically, however, that even RVs with special heated systems for their tanks and dump valves have a very difficult time when temperatures hover near 0 degree F.

Having noted the option which most manufacturers avoid due to cost and added complexity, let’s discuss what they do install to deal with the cold, remote dump valves. As the name implies remote dump valves are installed on the tank outlet above the sealed belly of the RV. In this manner, they are less subject to freezing, but a whole other type of problem is ushered in by using a cable to open and close the valve.

The most common problem cable operated valves have is the cable and valves are not installed according the manufacturer’s instructions and this problem is almost universal. Ideally the pull handle is installed in line with the action of the valve and and the cable is anchored at several points so it does not deflect when the valve is actuated.

In practice, however, cables are run in a variety of directions including S curves and are almost never (I have never seen a single one) anchored between the handle and the valve. Invariably as the valves are operated they gradually stiffen in action and increasing amounts of pressure are required to open and close the valve. Eventually the cable often pulls free of the valve body making operation impossible.

In another scenario, a bit of tissue may get into the valve so the valve will not close completely, never a good thing when the black tank continues to drip when the valve is closed.  Now for the record, a service call to work on a system with a stuck dump valve and a full tank is almost universally avoided by technicians, as emptying a full tank by disconnecting a dump valve is less than pleasant.

To avoid this problem, RV owners who own RVs with remotely controlled dump valves should routinely use tissue dissolver in the black water tank and valve lubricant in all their dump tanks. The first product makes tissue less likely to hang up in the body of the dump valve when it is opened. Valve lubricant eases the action of the valve and makes pulling the cable out of the valve less likely.

Since there are times when even the best efforts of owners are thwarted, there is one other thing I recommend owners with remote valves carry with then and that is a 3″ twist-on dump valve. This redundant valve be placed between the dump hose connection and the dump hose, in the event of an emergency. With this valve in place, the entire dump system can be contained in the RV’s plumbing, until the defective parts can be replaced. Replacing remote dump valves on-site is a difficult process that should only be attempted in an emergency.

Twist-On Waste Valve, 3"

For those folks wondering if they have remotely controlled valves, they are most commonly found in mid-range and higher priced fifth wheels. For example, Cedar Creek fifth wheels have remote valves as do Big Horn fifth wheels. In the case of Big Horn, the dump tanks are stacked and onsite repair is all but impossible (in my opinion), so you have been forewarned. A $25.00 twist-on valve is a godsend if your dump system fails on the road, so pick one up and toss it in one of the storage bins, just in case!

Hope to see you one the road,

Steve (Mobility RV Service 423.341.8792)

19 thoughts on “Remote dump valves in RVs, a good idea poorly designed and executed

  1. Hello Steve. This is a great article. I have a 2016 Sandpiper 5er that I’m having trouble with the stupid cable valve on the black tank. It will not close completely. I took it back to the dealer and they replaced the valve and fixed the leaking valve. I got it home and checked it so I wouldn’t actually be camping and it do it again. Well sure enough it began leaking out and wouldn’t seal off. The dealer did a good job of providing an access panel to the valve. I decided to diagnose the problem myself and have figured it out. When I had someone actuate the valve I noticed the rod was not going all the way in. I took my finger and pushed it in and it sealed completely. So basically what’s happening is the little cable rod is bending or the cable is flexing when the gate slides into the final side of the opening. It just isn’t rigid enough to push it the final 1/2″ to 3/4″. This is a brand new unit so I know it isn’t toilet paper. I’m sure the new rubber seals are obviously stiffer and just harder to seat. The OEM has way too much cable behind the panel and down into the underbelly and like you said it is not secured. One question I have is have you dealt with this and come up with a solution? Could the body bolts on the. Alve be too tight? My valve is a Valterra and the cable connection is just a u-bend through a hole in the rod. And next, are the electric actuated slide valves better. I really don’t want to add the twist on extra valve and have the pipe be an extension of the black tank. Only in an emergency. Your comments will be greatly appreciated.

    I’m glad to find you on here. I live in the Tri-cities as well.

    Thanks,
    Vance Gilmer

    • Vance,

      As you realize, those cable valves should not be used on RVs at all in my opinion. Black water valves need to close completely, and even when the cable works when first installed, it can stick or come off the rod if pulled too hard. There are a couple thing you can try.

      First, dump some “valve lubricant” into your empty black water tank and let it work its way to the valve. Then work the valve back and forth and see if that helps. For those who may not be familiar with valve lubricant, it is sold at most RV dealerships, but you can also find it on Amazon http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=rv+valve+lubircant where is also likely to be cheaper. In my opinion, valve lubricant should be used routinely with all black water cable valves. Gray water valves are much smaller and less likely to cause a problem.

      Next, as you suggested, the valve body itself is very tight to seal the seals against the knife part of the valve. You can try loosening four bolts in the corners of the valve just slightly and see if that helps. Sometime it does, but you can’t loosen them much or the valve seals will not contact the knife enough.

      A better fix is to leave the cable valve alone and add a solid rod actuated valve somewhere alone the 3″ line so you have a solid connection between the valve and the handle on the outside of belly. You can still find this type of installation on older fifth wheels. Although it can be a little tricky to do depending on how the 3″ line runs in the belly, the parts to do it do not cost much at all and I have never seen a solid rod actuate valve fail. This is a modification I intend to do on our own fifth wheel when I get time and I will post it when I do. Once you have the new valve in place, you just leave the cable valve open all the time. Remember, the valve can be placed anywhere under the belly on the 3″ line. The 3″ pipe has always been an extension of the black tank recalling where valves were located before the advent of enclosed bellies and they worked just fine and still do. 🙂

      A more expensive fix is to go with the electrically operated valves. I have also used them and they work just fine. You do have to power them, however, which means wiring and a 12-volt power source. The other thing to remember with the electric valves is they operate very fast so everything has to be connected before pushing that button!

      It is hard to remember how we all managed before we had heated bellies, but my fading memory says we did just fine. Folks who camp in below freezing weather are a bit of a novelty and until it gets really cold for more than an hour or two, enclosed bellies do little more than give critters a place to nest. Its another one of those RV things that adds as much disadvantage as it does advantage for most RVers.

      Enjoy you new camper,

      Steve

      • Thank you for the reply Steve. I also apologize as I didn’t see your note about not contacting you for info until I had already sent the note. I am an industrial mechanic by trade so this type item is right up my alley. I have found through the years that most dealership techs just don’t have the background to troubleshoot and diagnose the problems. I always like to discuss these issues with professionals, as you may have seen the problem and know of a trick that I may never think of. I understand you make a living doing this and could probably spend all your time just answer questions on the phone, emails, blogs, etc. which doesn’t make you a dime. Again I appreciate your reply and advice. I will definitely put your name/number in my phone and maybe give you some paying business one day. Concerning my unit, first I’m going to try to secure the cable in at least a couple places close to the tank and at the handle location then second I’m going to try to make the connection at the cable to rod location a little stiffer. If that still doesn’t work, I may try to get my dealer to make me a good deal on an electric replacement.

        Regards,
        Vance Gilmer

        • I actually am glad to answer emails and posts to my blog. I just ask folks don’t call me on the phone, which amazingly still happens frequently. The course of action you are pursuing makes sense. I hope it works for you. Often there is no good place to secure the cable.

          Steve

  2. How do you reattach the cable to the value? My is no longer attached, so when I pull the handle to open the value, the handle come right out with the cable wire coming out, but the value does not open. How do I reattach it?

    • Crawl under your RV and locate the dump valve to which the cable is supposed to attach. If you camper has an enclosed belly, you have to cut an opening in the belly. The cable is held to the valve with a small allan screw. Slip the cable back into place and tighten the screw. How hard this is to do depends on how hard it is to locate and reach the dump valve. To keep it from happening in the future, keep the dump valves lubricated so they open and close easily. Forcing them when they stick normally will cause the cable to pull free.

      This is one of those repairs I normally take a pass on. It can be a real pain to fix.

      Steve

  3. we have a 2009 fuzion 393 with both black and grey water dump valves that are very hard to open or close. Both are cable valves. Is it possible to lube the cable to make them easier to operate? And what kind of lube would you reccomend?ro

  4. Is there some way to convert the cable valve system so that it operates like a regular system — adding an extension or something? My black water cable is very difficult to operate.

    • It is possible to change it to a rod operated system depending on the position of the valve, or if you do not camp in freezing weather, you can simple add a valve where it is exposed. You may also want to consider an electric valve that once installed, opens and closes with the push of a button.

      Cable valves typically work very poorly because manufacturers often fail to install them according to instructions. I regard cable operated valves as something that should be done away with given how much trouble the create for owners.

      Good luck,

      Steve

  5. I have had a 12volt value put on my black waste tank. This is good, except I would like to have a second switch located inside the RV. So far, my tech says this is not possible before of the way the switches operate. I was wondering and hoping that I could get a remotely activated value and get 2 remote controls. Does anyone make these?? Thanks

    • I can’t find any catalog listing for what you want. I doubt there is enough demand for a manufacturer to make one.

      Thanks,

      Steve

  6. We have a cable flush system for both black and gray water in the bathroom.When showering recently,the shower drain did not empty although the gray water valve was pulled open.This is a really stupid system.These design geeks should spend 2 weeks in an RV before they sign off them.Any idea on fixing my gray valve problem?
    Thanks

    • If the handle to the cable is pulled and the shower is not draining, the valve is not open, most likely because the cable has pulled out of the valve. There is really nothing that goes down the shower drain that can clog the drain line. And yes, it is a very poor system. Like many things in RVs designed to save money rather than function well!

  7. Rv is an 08 Bristol Bay with three dump valves. Went to dump black tank into :blue boy portable tank” and handle where it attached to wall bacame loose. Appeared the two nuts on either side of the wall became loose. In my efforts to get things back together I pulled on the black water handle and now it will not close at all. The valve is a solid slender fixture with the cable entering from th end. Any idea how I might free the cable (?) so I can close the valve or make/model of valve so I can look on internet. Appreciate any input you can provide.

    • The only way you are going to make things right is to get to the valve itself where it has come apart at the tank. In the short term, for about $20.00 – $30.00 you can purchase a secondary valve that will go on the part you fasten your dump hose too and you will be able to open and close the secondary valve when you want to dump your tanks.

      Steve

  8. who sells the threaded spacer that passes through the RV frame and has a hex opening for the t-handle to “seat” in when closed and travel through when pulled into the open position. One of these plastic/nylon fittings has broken so the T-handle hangs when in the open position and makes it nearly impossible to push into a closed position.

    • Man, sorry but I don’t think that part is available separately. One of the things you can add to the “why I hate remote cable dump valves” is you have to buy the whole darn thing to get the parts. Off the record, you might try calling the manufacturer directly. Sometimes they will send you a part for free that is not listed in the catalog. Otherwise I would try to fab one using plastic spacers like you can get in Lowes in the specialty parts section of the hardware section.

      Good luck,

      Steve (mobility rv service)

    • It looks exactly like the valves you can see, when they are not remote. The only thing that changes is there is a fitting on the valve to which the cable attaches. Just take a look at a 3″ dump valve on a dealer’s shelve and you will be looking at a remote valve without the cable.

      Steve

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