Zion dual dump system

[Davydd]

I disagree about a single tank. The grey and black tank sequence makes for a cleaner operation when you can flush almost all the black tank water with what is mostly soapy grey water at an almost 2 to 1 ratio. If you combine the tanks you are going to have crap from beginning to end. And greater smell issues when your traps dry out. On top of that in a B it may be impossible to find space for a single waste tank equal two two separate tanks as waste tanks shouldn't be rotomolded into an odd shape like fresh warer tanks can to find the extra space. There are a lot of practical reasons for two tanks.

[avanti]

Originally Posted by Davydd

I disagree about a single tank. The grey and black tank sequence makes for a cleaner operation when you can flush almost all the black tank water with what is mostly soapy grey water at an almost 2 to 1 ratio. If you combine the tanks you are going to have crap from beginning to end. And greater smell issues when your traps dry out. On top of that in a B it may be impossible to find space for a single waste tank equal two two separate tanks as waste tanks shouldn't be rotomolded into an odd shape like fresh warer tanks can to find the extra space. There are a lot of practical reasons for two tanks.

I could not disagree more.
--First of all, gray tanks almost always smell worse than black tanks. Not sure why, but this is generally accepted to be true. As I said, I had eight years experience with a single tank, and I can assure you that there are no practical issues having to do with odor or filth. In fact, quite the opposite is true: A very common problem involves solids build-up in the black tank due to insufficient liquid. Obviously, a single tank greatly eases this issue. Finally, most solids tend to sink, and so drain out first anyway. Not that it matters much, since (as we both agree) a sealed macerator system is the way to go, and a "clean" system makes little difference there.
--As for finding space: (a) All else being equal, a single large tank obviously can have a higher capacity than separate tanks, since there is less structural overhead; (b) There is no reason that a combined tank can't be rotomolded into odd shapes. I understand why you would say otherwise, but the odd shapes in B-van tanks are always near the TOP of the tanks, not the bottom. As long as the bottom of the tank is not irregular, all will be well; and (c) even in the unlikely case that one was forced into two tanks, there is absolutely no reason why they couldn't be connected. As long as this were properly engineered, one could have the advantages of a single tank and still accommodate odd layouts.

I have now had significant experience with both systems, and I can assure you that there are no real-life disadvantages to a single tank, and very real advantages, including significant weight-, cost-, and space-savings, as well as better performance and simplicity in dumping. There was a time when separate gray tanks made some sense, but that time is long gone. There are NO good arguments for the status quo, except that "that is how we've always done it". Unfortunately, that is how most decisions are still made in the RV industry.

[booster]

Originally Posted by Davydd

After flushing with grey water I am finding the pipes pretty clean. I don't think it will be a problem. Besides as Avanti mentioned, it is a remote situation and something not to agonize over. Booster, you did your mod because Roadtrek doesn't have its act fully together. Jim Hammill would not commit to the Zion system for the other Roadtreks. Could it be because they designed themselves in an impractical situation putting bathrooms on the passenger side?

You may be "pretty clean" when you finish dumping, but your pump is most likely to fail or jam when you first start to dump, not when you are done, from all I have read. At that point, you have the worst of stuff at the inlet to the pump, not cleanest. Remote situation, yep, absolutely, but you optimized everything else to the max and this would be one more thing that could be made better by adding one valve and a cover.

I am not surprised that Roadtrek won't commit to the other models, as they are always a bit hesitant on anything that might infer the existing setups aren't very good. I think the Zion acceptance and attention will probably change that. Hopefully, it will also include upgrade kits for the older units, too.

Having the bathroom on the passenger side is a minor issue in doing a dual dump system IMO, as we showed on ours. The only downside is that you need either a longer pipe to the dump system from the tanks if you put the system on the drivers side, or a long pipe from the system outlet to the drivers side if the pump stays on the passenger side. No big deal either way. The advantage you do get with having the waste tanks on the passenger side is that they can be bigger because you don't have the dump system taking up space between the the tanks like you do with the tanks on the passenger side. On a 24 footer, it is not a big deal, but when you get shorter, it can make a big difference.

[booster]

I have to agree with Avanti on the single tanks, I think. Although we have never lived with a single tank, it just makes sense to us. We rarely have solids in our black tank, and are stingy water users, so we can go a week or so pretty easily without dumping. That puts pretty concentrated liquids in the the black tank for extended times. When I did the conversion to the dual dump, I found the blank tank, sensors, plumbing to the pump, valves, and pump inlet to be full of a white coating of built up something. It easily would scrape off to a white powder, but would not flush out. 409 cleaner did not dissolve it. The grey tank did not have it in it. We think it is because of the concentration and extended time between dumps. If we had a single tank, we would still have the time period, but would be substantially diluted. We often open both valves after dumping the black tank to rinse the black tank with the grey water.

[gerrym51]

isn't there some rule or law on this. I read an article awhile ago-i can't remember where-that many moons ago black and gray was mixed in 1 tank-then rvia rules prohibited.

i 've looked at many rv's and they all seem to have separate tanks.

also i have read posts of people on the exepedtion portal dumping gray on ground in boonies-since gray usually fills much quicker-you would have no good option with 1 mixed tank

[avanti]

Originally Posted by gerrym51

isn't there some rule or law on this. I read an article awhile ago-i can't remember where-that many moons ago black and gray was mixed in 1 tank-then rvia rules prohibited.

I have heard this rumor before. I once looked it up in the RVIA spec. The only thing I could find was a provision to the effect that "gray and black tanks shall not be interconnected upstream of the dump valves" (that is a paraphrase). Does having a single tank count as a "connection"?

Also, as I said, my 2005 Airstream Interstate came with a single tank, so Thor thought it was legal, at least 10 years ago.

Even if this claim were true, I would merely offer it as yet another symptom of the backwardness of the RV Industry.

i 've looked at many rv's and they all seem to have separate tanks.

also i have read posts of people on the exepedtion portal dumping gray on ground in boonies-since gray usually fills much quicker-you would have no good option with 1 mixed tank

That is certainly true, but it is now illegal almost everywhere.

[gerrym51]

Avanti- alot of things are illegal. people do them anyways.-in my other rv's i have never dumped anywhere but a dump site and don't intend to with my b.

however the people at the expeditionersportal are really in the middle of nowhere. the ability to just dump the gray tank would be useful

[avanti]

Originally Posted by gerrym51

Avanti- alot of things are illegal. people do them anyways.-in my other rv's i have never dumped anywhere but a dump site and don't intend to with my b.

however the people at the expeditionersportal are really in the middle of nowhere. the ability to just dump the gray tank would be useful

Agreed. I am not claiming that there is no place for dual tanks; merely that they make little sense as the default for mainstream RVs.

[markopolo]

IMO - a dual dump system lets you choose whether to use the macerator or gravity dump without having to remove the pump. I added a macerator to a van that could easily be removed if it failed so as to not unduly interrupt a trip but did not consider it a dual dump system. I would not have removed the macerator when at a full hookup campsite to allow free flow from the grey tank while taking an extended shower for example.

Another way to describe it would be no bucket needed when switching between gravity dumping and macerator dumping. My setup would have required a bucket.

The other manufacturers will have to catchup to Roadtrek on this. As booster noted, it looks so easy to do - no need to complicate it or make it messy. It's bound to become commonplace like how we see just about every B manufacturer offering solar panels now.

As with many improvements from manufacturers these solutions are often first done by the DIY community.

[booster]

Originally Posted by markopolo

IMO - a dual dump system lets you choose whether to use the macerator or gravity dump without having to remove the pump.

The other manufacturers will have to catchup to Roadtrek on this. As booster noted, it looks so easy to do - no need to complicate it or make it messy. It's bound to become commonplace like how we see just about every B manufacturer offering solar panels now.

As with many improvements from manufacturers these solutions are often first done by the DIY community.

You never know, Roadtrek may have been following the myriad of ideas and discussions that have been going on in the Class B Forum about dumping, and decided to make our wishes come true! The system they did does take care of all of the issues we have ever discussed, assuming the pump is rightside up I think they did very well.

[avanti]

So, I guess if I want my new setup to be fully "Dual dump certified", I could add one of these to my slinky connector:




It is Valterra T58. It always amazes me how many obscure and useful fittings Valterra produces.

[gerrym51]

how about this. your traveling. your gray tank is nearly full. your black not close. you pull into a rest stop that has no dump but does have bathroom.

you can put a few gallons of gray water into a bucket(or other thing) and dump in the rest stops toilet. you could dump a few gallons into your own toilet but that would make total dumping be sooner. lots more options with dual tanks

[gerrym51]

Originally Posted by avanti

So, I guess if I want my new setup to be fully "Dual dump certified", I could add one of these to my slinky connector:




It is Valterra T58. It always amazes me how many obscure and useful fittings Valterra produces.

they are not obsure to valterra

[markopolo]

"Dual dump certified" love it

Needs a red handle though!

[booster]

Originally Posted by avanti

So, I guess if I want my new setup to be fully "Dual dump certified", I could add one of these to my slinky connector:




It is Valterra T58. It always amazes me how many obscure and useful fittings Valterra produces.

You should be able to get whatever you need to put a glue on valve flange on your cross fitting. I used one on the end of my pipe where the extra valve goes on. It really shortens up the assembly. The other flange on the valve would be a bayonet for the slinky.

[booster]

Originally Posted by markopolo

"Dual dump certified" love it

Needs a red handle though!

I think Marko has a basis for his new business model--"Dual dump/handle inspection, testing and certification"

[gerrym51]

Who would have thought the zion's dual dump would be an-exciting topic. this van and spring better get here quick. we are going stir crazy.

[booster]

Originally Posted by gerrym51

Who would have thought the zion's dual dump would be an-exciting topic. this van and spring better get here quick. we are going stir crazy.

It could just be that this is one of the big time surprise things that has a much bigger impact than anyone thought it would. It will be interesting to see how Roadtrek advertises it, and the others brands react to it. Also very interesting that it first appeared on a lower end model and not a high end one. I wonder if Roadtrek tried to get any kind of patent on it? I think it would be tough to do, as it is not all that unique, but even a "patent applied for" can scare some others.

[gerrym51]

Originally Posted by booster

It could just be that this is one of the big time surprise things that has a much bigger impact than anyone thought it would. It will be interesting to see how Roadtrek advertises it, and the others brands react to it. Also very interesting that it first appeared on a lower end model and not a high end one. I wonder if Roadtrek tried to get any kind of patent on it? I think it would be tough to do, as it is not all that unique, but even a "patent applied for" can scare some others.

i am not an engineer. to put this on their earlier models would 'probably' require design changes underneath. the one advantage of the promaster chassis-although it's low-is that since its front wheel drive underneath pas the cab is 'practically' an empty flat space-only have to work around spare-if it stays(i will have spare underneath) and exhaust pipe-only Jim Hammill could say

[avanti]

Originally Posted by gerrym51

how about this. your traveling. your gray tank is nearly full. your black not close. you pull into a rest stop that has no dump but does have bathroom.

you can put a few gallons of gray water into a bucket(or other thing) and dump in the rest stops toilet. you could dump a few gallons into your own toilet but that would make total dumping be sooner. lots more options with dual tanks

Ah!, but if you had a single tank given your scenario, that tank would still be "not close" (assuming a similar total capacity). That is exactly part of my point: with dual tanks, you are stuck with a fixed ratio between grey and black capacity. With a single tank, all the capacity is fungible.