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Waste Valve Repair Questions


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I am not sure if it is unique to Travel Supreme or not, but our 5th wheel has the waste valves located between the black and grey tanks up under the center of the trailer. The discharge side of the valves tees together to a pipe that comes out to side of trailer where sewer hose attaches. The valves are operated with cables.

 

We have a leak at the valve for the black tank. Yea...yuk!

 

I removed some of the metal underbelly and found the general leak area. I still don't know exactly where the leak is. It could be that the gaskets in the valve are leaking. Or it could be leaking where the 3" black ABS pipe connects on one or both sides of the valve.

 

Question #1: Anyone know a good trick to determine exactly where it is leaking?

 

I first thought I would just cut out the valves and replace both, glueing in a new 3" tee between them and new couplings to make it all fit. As I thought about the design, I realized fitting the couplings, valves, and tee together would be impossible in between the two tanks. I don't think I could even do it with Fernco type rubber couplings. In order to understand the problem the narrow space between the tanks presents, See this linked photo. (Note: The photo was taken as if you were laying down underneath the trailer and looking up at it. That pipe on left runs downhill to side of trailer. You can't see the tanks, but they are right at the top and bottom of the photo.

 

Question #2A: Can these valves be installed disassembled in halves and joined with the screws after the halves are glued to the pipes?

Question #2B: Is there such a thing as a 3" ABS union fitting that would allow me to slip the tee and assembled valves in between the tanks and connect it all up?

 

Question #3: If I am able to determine that the glued assemblies are not leaking, and it's these Thetford 08761 valves themselves that are leaking (see question #1), would I be able to use a rebuild kit to rebuild my valves? This one says "Slide-EZ Valve Repair Package contains all seals to repair any plastic covered thetford termination valve." I would be more comfortable ordering it if it specifically said it works with the 08761 Valve.

 

Question #3B: Is it better to replace the whole valve? I really don't want to ever need to do this again!

 

Question #4: Is there another valve anyone would recommend? Seems like someone posted someplace that they went with electric valves.

 

Thanks for your help!

 

Jim

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I had a long reply written for you but realized it would not fix your type of valves. Personally I would do some reply,Bing and get everything out where I could have exposed valves. If that is not feasible look at this

 

http://www.vintagetrailersupply.com/Thetford-Repair-Kit-p/vts-616.htm

 

I reply,bed all my valves to the exterior. The buried valves are still there, just remain open because I didn't want to have this problem.

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A couple years ago I had an intermittent leak form the black or a grey tank. I put half a small bottle of red food coloring into the grey tank to determine which tank had the leak. It was easy to see the red dye in the leaked water. It turned out to be leaking from the shaft entering the valve assembly which was attached to the handle used to open the valve. I was going to have some service work done so had both (as long as they were so close together) replaced. As you said you don't want to do it again so I'd suggest total replacement. Greg

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Rewording Question #2A - If you look at the photo of my valves... if I remove all the screws that hold both the halves of each of the white valves together, will I be able to pull the center section of the plumbing assembly out with the tee and black pipe going to sewer hose? More important...should I be able to put it back together that way without damaging the seals?

 

I will replace both valves, but this may be the only way to physically make the connections go together.

 

Jim

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Jim, your picture shows a wye fitting as the tee. A trick I used more than a few times for removing glued fittings is to use a saw to cut through the part you want to remove (I have done this for pipe inside a fitting too) then use a heat gun or a propane torch to heat the part slated for removal. You need to get it quite hot (it will become soft and pliable) and use pliers to grab one end of the pipe/fitting and start winding it up with the pliers. You can then reglue another pipe/fitting back where you removed the piece of what you removed. Don't get concerned about the rough surface, just use primer and a good heavy coating of glue. Chances are you will only need to repair the valves. I would just pull the bolts on the valves and rebuild the valves.

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Not sure how All Brand RV Repair replaced the Thedford valves in our Travel Supreme. Our valves were starting to stick and after understanding that one side of the Thedford valve is glued to the tank, we figured we get the valves replaced by someone who knew what they were doing before a crisis.

 

Depending on how busy they are, the folks at Precision Painting RV will admit to knowing how to do it also.

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Are you sure you can buy a rebuild kit for those particular valves? Something must move apart in order to install new valves or even get those old ones apart to install a rebuild kit. Looks to me like one tank must be movable in order to accomplish either a rebuild or install new valves.

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There are rebuild kits for Thedford valves but the assembly of the two tanks, Y and the valves were assembled outside of the frame and then inserted into the frame. The connections on the valves to the Y slip with O-rings but there is not enough movement in either tank to allow the valve to be slipped off of the Y.

 

The Thedford valves last a whole longer than the typical Valterra valves but not enough for a permanent install which is just about what Travel Supreme did.

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The best suggestion I can give is have someone else do it. I had to repair/replace ours on our previous trailer. It's a bad, bad job. No matter how clean that black tank is you are still working underneath all that mess.

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But with that said I had problems with the new seals becoming distorted when I tried to slide the two valve halves together. Ended up replacing the valve. Had to saw the pipe and then used a Fernco Coupling.

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When the job was done my clothes went in the garbage bag and it took days to get that smell out of my nose. Like I suggested, have someone else do it.

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To me, I think that there is a strong possibility that the discolored area on the black tank valve may be where your leak is located. All of the waste valves that I have worked with are of the Valtera type and now I see why they are so popular. If you want to replace those and stay with the Thetford, then I would use this kit to make them removable. Even with that change the spacing of thins is such that it will be difficult to work on so it might be better to completely redesign and reroute the entire thing, getting the valves our where they are accessible. Unfortunately, most RV designs give little or no thought to future need for repairs.

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No, that was if staying with Thetford. Converting to that version should make the valves removable, if I read the explanation correctly. The Valtera valves are removable by design and that kit seems to make that possible with the Thetford valves.

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One of my valves is giving just a bit of resistance and getting a look at the valves is on "the list" of things to get to. As you know, we have sister 5ers and looking at your photo is giving me some pause and not sure how/whether to tackle this. Here's some thoughts:

 

- relocating the valves to where they're exposed has appeal but may compromise the freeze protection and offers a plumbing challenge that may not be feasible

- as mentioned, the Valterra valves are designed to repair without disturbing the piping, unlike our Thetford valves

- a repair approach might be removal of the valves and using heat to peel away the Thetford slip flange from the pipe that exits the tanks

- make up a new tee assembly using Valterra cable operated valves. Glue the new slip flanges on the tank pipes and bring the rest of tee and valves assembly to mate to the slip flanges. Of course, dry fit and mark the joints before glueing the assembly. The valterra valve body may be wider, so you'll need to have good handle on dimensions before going this route.

 

Having said all this, I have to say taking it to someone that's done this before seems like the wise thing to do . . . but you deny yourself the memories!

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Thanks everyone for all the advice so far. Jim - I was also thinking about how nice it was to have the valves up in the insulated belly of the trailer, at least until they need repair. Changing over to Valterra valves might have merit, but these have lasted over 10 years and replacing with the same that I am removing won't be as hard on my non-engineer brain. Mark- I sent an e-mail to All Brands RV Repair with my photo a couple hours ago. I will follow up with a call to them, as they have not called me back yet.

 

Now the good news... I went back out with better lighting this morning and less reliance on the camera images I was getting by reaching up and shooting relatively blindly until I saw something in a picture. It turns out that there is more space between the grey tank and valve than I thought. It looked to me that the valves were centered between the tanks with only a few inches on each side to play with. That is the case on the black tank side, but the grey tank side actually has a foot or more of 3 inch ABS between the valve and the tank. SEE SKETCH HERE

 

My tentative plan now is to start gluing joints from the black tank side and install a rubber Fernco coupler in the longer grey tank side. How does that sound?

 

I have not done much plumbing, (I don't know a tee from a wye...thanks, MnTom) so I am not sure how much space I need to cut the 3 inch diameter ABS and reinstall with couplers. Looking at the sketch you will see there is 4 inches of 3" ABS pipe between the flange on the black tank and the collar on the valve. There is only 3 inches of 3 inch ABS pipe between the discharge end of the wye and the tee for a vent pipe connection. Can I cut it off in that 3" between the wye and the tee and have room for a coupler? It seems like the couplers may be more than 3 inches long. I guess I could cut one down. Or I could cut the vent line instead and put a coupler in that line. That may be best?

 

With consideration not only on how to make it easy now, but also for when it needs repair next time, can anyone with plumbing experience make any suggestions before I order valves and start cutting pipes off?

 

Jim

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Jim, I'd be inclined to use the Fernco couplings on both valves if you can make it work. The short side would have a couple 2-3 inch pipe stubs and you'd have to slide on that joint first. The other side has plenty of room to line it up and slide the coupling over the joint. Should there be a next time, you can disassemble mush easier and won't have that glued in coupling to deal with.

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I think you have it figured out. As long as your valves have lasted, you should be ok with repair. I have a ferco type coupler on the pipe for my macerate pump. It allows some flex and prevents cracked pipes due to vibration. If we were there you could have our DW's go shopping together. That would give you all day to work in it. Fill the tank up and dump several times the flush foe a good 30 minutes. You want to eliminate all the surprises you can.

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Cathy says she would enjoy a day with Terresa. Another time maybe. We plan to spend more time in the Western US after we get back from Alaska. Maybe sooner if don't get to Alaska this year. You're in our thoughts and prayers.

 

Cathy and Jim

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Jim, before you go and cut things apart remember that you do not need a lot of room to rebuild the valves. I would look at cutting a 2x4 or something similar that would fit between the outlets on the tanks. Cut that board in half and the cut a wedge to drive between the previously cut boards. All you need is 1/8" of clearance once you get the bolts out of the valve so you can separate them. Then I would repair one valve, put it back together and then repair the other one.

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