Gray/black tank dump problem....am I nuts or factory screw up?

cmarkj

Member
Joined
Apr 12, 2014
Messages
15
Location
Illinois
I will be as brief as I can be. I just bought a Denali 289RK. It has 2 gray tanks (one up front and one in the back). The one in the back is for the kitchen and has its own dump valve. The one up front is for the bathroom and is tied in with the black tank.
Normally when the black and gray tanks are tied together, the gray ties into the dump line down stream from the black tank valve so you can dump the gray if it is full and the black tank can stay isolated (correct so far??)
The under carriage of the Denali is all sealed so I can't see what is going on, but I know one thing for sure right now......in order to dump my front gray tank, the black tank is dumping right along with the gray tank. The gray tank is tied into the dump line up-stream of the black tank dump valve, not down stream to be able to keep the black tank isolated.
I really hope I haven't confused everyone, because I need some help. If this is designed this way, and not a build screw up, all their engineers should be fired.
Their paperwork says that the black tank level should be at least 3/4 full before dumping the tank. The way it's set up now, if the gray is full and the black is at 1/4, the black is getting dumped way too soon
Please help me
 
There may be another dump valve hidden away up in there somewhere. It took me a while to find a dump valve for the second gray tank. It was hidden between the wheels and was sort of forgotten because the other gray tank valve is in the compartment with the black tank valve.

We fired the engineers a long time ago if that hepls.
 
Don't have your unit but it doesn't sound right to me. If the gray tank valve is upstream of the black, you have to pull the black tank valve in order to dump the gray tank? If that's the case, it sounds like they got the y-tube for the gray on the wrong side of the black valve. Sounds like an error to me but with everything else that goes on with these units who knows. From what you said it sounds like you've had a trailer before. Is it new? If not, could this be a repair that the previous owner got wrong. If its new take it back to the dealer and get them to explain.
 
Just a guess but maybe the black tank valve isn't closing? Cable broke maybe in open position? Thus causing it to back up to gray tank, so when gray is opened here it all comes. Cables can be a problem. If you have them?
 
I have the same trailer, 2014 289RK. My tanks are hooked up the same way. I could not believe this when I noticed.

To drain the gray tank you have to drain the black first as you stated.

Not sure at this point what I am going to do about it.
 
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I have the same trailer, 2014 289RK. My tanks are hooked up the same way. I could not believe this when I noticed.

To drain the gray tank you have to drain the black first as you stated.

Not sure at this point what I am going to do about it.

That sure is not the right way for it to be plumbed. On a side note I always drain the black tank first before the gray. That way it helps clean the hose out some. Don't think I have ever needed to drain the gray & not drain the black.
Is it both grays that are plumbed up stream or just one ?
 
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I will be as brief as I can be. I just bought a Denali 289RK. It has 2 gray tanks (one up front and one in the back). The one in the back is for the kitchen and has its own dump valve. The one up front is for the bathroom and is tied in with the black tank.
Normally when the black and gray tanks are tied together, the gray ties into the dump line down stream from the black tank valve so you can dump the gray if it is full and the black tank can stay isolated (correct so far??)
The under carriage of the Denali is all sealed so I can't see what is going on, but I know one thing for sure right now......in order to dump my front gray tank, the black tank is dumping right along with the gray tank. The gray tank is tied into the dump line up-stream of the black tank dump valve, not down stream to be able to keep the black tank isolated.
I really hope I haven't confused everyone, because I need some help. If this is designed this way, and not a build screw up, all their engineers should be fired.
Their paperwork says that the black tank level should be at least 3/4 full before dumping the tank. The way it's set up now, if the gray is full and the black is at 1/4, the black is getting dumped way too soon
Please help me

As I am new to the whole RV trailer life, I am not understanding why the black tank would need to get to the 3/4 level before dumping.
The issue that you are describing to my unskilled thought process is that having a constantly clean and flushed black tank by using the gray tank to flush the black tank and drain hose would be a positive thing. Where are my thoughts wrong on this?

Help educate a new person!
 
Hi Alan, there are some advantages to the unit being plumbed this way. As you say, you could drain the black tank, close the black valve and use the gray tank to flush clean the black tank. Then open the black tank to flush the hose. I would want to do this several times in order to keep the gray tank clean. The biggest issue I see is that full timers or just weekend campers like to leave the gray tank open so it drains straight into the sewer so you never have to worry about it filling up in the middle of a shower. The day or so before you drain the black tank you then close the gray tank and let it partially fill in order to use it to flush the drain hose. Most units are not plumbed the way this 289RK is and its got a lot of us wondering the purpose.
 
Thank you for the quick response.
Being new to this is going to make the learning interesting!
Very shortly I will be full timing with full hookups initially, but will be taking some short trip boon-docks to fully acclimate myself to the particulars of the V3605 TH I take delivery of this week.
 
Good luck with the delivery this weekend. As has been explained, have all your ducks in a row during the pre-delivery inspection. Much easier to get things fixed while they're still interested in pleasing you.
 
That sure is not the right way for it to be plumbed. On a side note I always drain the black tank first before the gray. That way it helps clean the hose out some. Don't think I have ever needed to drain the gray & not drain the black.
Is it both grays that are plumbed up stream or just one ?

I always dump the black first too when I'm going home. The black tank is 42 gal and will last us quite a few days, much longer than the gray tank will last with showers and all. If you can't dump the gray tank independently from the black tank, you loose a lot of functionality especially if you are camping without sewer hookups. I could make the black last 13 or 14 days, but there is no way I could do that with the gray tank without DW and myself both using the CG shower facilities and sinks. And if we did that, I might as well go back to my old pop-up.
 
My 2004 Dutchmen Classis RK has a galley tank, a grey tank and black tank with the discharge value at the tank. The black and grey tanks drain to a central discharge pipe and the galley tank had it's on discharge pipe. I installed a pipe for the galley tank to discharge at the central discharge pipe. That way I have only one discharge hookup. On the point of why you want the black tank 3/4 full before flushing, it's simply to have enough water force to discharge the solids in the tank. I dump my tanks whenever I leave campground but try to fill the black tank every 3 or 4 dumps. If no one is in line at the dump station, I get my Flush King out and give the black tank a good cleaning.
 
A quick update...I brought my new TT to a local Denali dealer and after sending pics to the factory and a report of what they were seeing, everything has been put right. And for that, at this point, I am a happy customer.
 
A quick update...I brought my new TT to a local Denali dealer and after sending pics to the factory and a report of what they were seeing, everything has been put right. And for that, at this point, I am a happy customer.

That's great, any chances of you posting the before and after pictures.

I contacted my service department, and have not heard back from them on this. The pictures will help me get my valves corrected properly. My other argument with them on this is that the black valve is not in the heated belly, so it must be wrong.

On a side note, I have absolutely no other problems with my 289RK itself. The only issue is the front TV has a red line going through the screen when its on, which is not Dutchmen's or the Dealers fault, but should be under warrantee. I am very happy especially after reading all of the problems that others have with all types of trailers. And I will be really happy if they change my plumbing to the way it is supposed to be.
 
That's great, any chances of you posting the before and after pictures.

I contacted my service department, and have not heard back from them on this. The pictures will help me get my valves corrected properly. My other argument with them on this is that the black valve is not in the heated belly, so it must be wrong.

On a side note, I have absolutely no other problems with my 289RK itself. The only issue is the front TV has a red line going through the screen when its on, which is not Dutchmen's or the Dealers fault, but should be under warrantee. I am very happy especially after reading all of the problems that others have with all types of trailers. And I will be really happy if they change my plumbing to the way it is supposed to be.

Unfortunately, I was not smart enough to get before pics. I can take after pics, after I pick it up. I am assuming that all is well from what they told me on the phone. Another valve was added which is what I know needed to be done.
 
Unfortunately, I was not smart enough to get before pics. I can take after pics, after I pick it up. I am assuming that all is well from what they told me on the phone. Another valve was added which is what I know needed to be done.

I finally had a few weeks from camping and took my TT to the dealer for some minor warrantee repairs. I have asked to my valves redone properly.

I have no idea if they are going to do it or not. My main argument was that all the valves should have been in the belly to allow for heating during the winter so they don't freeze.

If you ever have a chance, I would really like a picture of the repaired valves in case I have to argue with the dealer on getting mine fixed.

Here are pictures of mine, I assume yours looked the same before the repair.
 

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If you ever have a chance, I would really like a picture of the repaired valves in case I have to argue with the dealer on getting mine fixed.

Here are pictures of mine, I assume yours looked the same before the repair.
I know this is kind of an old thread but it got me curious about how my 2012 Denali 289RK is plumbed. Here's the photo of my layout. This is from the front looking toward the rear. It appears to have two independent valves tied to a common drain fitting through a Y connection.
 

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I know this is kind of an old thread but it got me curious about how my 2012 Denali 289RK is plumbed. Here's the photo of my layout. This is from the front looking toward the rear. It appears to have two independent valves tied to a common drain fitting through a Y connection.

I think your fine. I only see one handle in the picture, but I am assuming there are two. One for the Gray and one for the black. And you most likely have another connection in the rear for the kitchen gray. Plus your valves are in the belly protected from the weather like there supposed to be.
If you look at the picture I posted earlier, the black is the valve you see outside of the belly, you have drain the black and leave it open to drain the gray. I am still working to get mine fixed.
 
I think your fine. I only see one handle in the picture, but I am assuming there are two. One for the Gray and one for the black. And you most likely have another connection in the rear for the kitchen gray. Plus your valves are in the belly protected from the weather like there supposed to be.
If you look at the picture I posted earlier, the black is the valve you see outside of the belly, you have drain the black and leave it open to drain the gray. I am still working to get mine fixed.

Your assumptions are correct.
Good luck with getting your's corrected.
 

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