Holding Tank Question

[wootond]

I have a 2021 Transend 30rbs and has 2 Gray Tanks. Bathroom sink and shower gray tank 1 and kitchen gray tank 2. The issue is my kitchen sink is filling gray tank 1 and not gray tank 2 as explained at the dealership and researching the issue. . Is there a valve to switch it to gray tank 2 from gray tank 1 or am I missing something basic. In the owners manuel there is nothing that shows or trouble shooting. Any advise, suggestions or resolution would be great. Thank you

Douglas
Southern California

[Cate&Rob]

I have a 2021 Transend 30rbs and has 2 Gray Tanks. Bathroom sink and shower gray tank 1 and kitchen gray tank 2. The issue is my kitchen sink is filling gray tank 1 and not gray tank 2 as explained at the dealership and researching the issue. . Is there a valve to switch it to gray tank 2 from gray tank 1 or am I missing something basic. In the owners manuel there is nothing that shows or trouble shooting. Any advise, suggestions or resolution would be great. Thank you

Douglas
Southern California

Hi Douglas,
Welcome to our owners technical forum.

How are you determining which is grey tank 1 and which is grey tank 2? Perhaps they are mislabeled on the panel or the valves? The tanks are typically in separate locations without a valve/switch to select from one to the other.

Rob

[wootond]

Hello Cate and Rob,

Sorry for the delay reply, in regards to your question back. We recently got back from at 10 day trip to Texas. While various days of dry camping the front tank Grey #2 was dry the entire trip.
The grey tank in the rear of the trailer did get maxed out and when I used the dump station I drained the rear tank and went to drain the front tank and it was dry?

[howson]

Cate&Rob -- see post above...

[TucsonJim]

Hello Cate and Rob,

Sorry for the delay reply, in regards to your question back. We recently got back from at 10 day trip to Texas. While various days of dry camping the front tank Grey #2 was dry the entire trip.
The grey tank in the rear of the trailer did get maxed out and when I used the dump station I drained the rear tank and went to drain the front tank and it was dry?

Wootond - I pulled the drawings for your 30RBS and what you are seeing is expected.

Gray #2 is only plumbed for the washing machine and has a capacity of 29 gallons. If you're not using a washing machine, it will stay dry.
Gray #1 is plumbed to the kitchen sink, shower, and bathroom sink. Its capacity is 39 gallons.

In addition, your black tank has a capacity of 39 gallons.

Just a suggestion. If you do a lot of boondocking and want to maximize your gray capacity, you could do your dishes in a plastic tub, and then dump the contents down the washing machine drain. We do something similar when we're dry camping so we can extend our gray tank capacity.

Jim

[Yoda]

Hello Cate and Rob,

Sorry for the delay reply, in regards to your question back. We recently got back from at 10 day trip to Texas. While various days of dry camping the front tank Grey #2 was dry the entire trip.
The grey tank in the rear of the trailer did get maxed out and when I used the dump station I drained the rear tank and went to drain the front tank and it was dry?

I see Jim got the answer to you. On your unit do the gray and black tank drain plumbing connect and exit at one port? If so you when your boon docking and need more space in the gray tank you can add an external gate valve and be able to open the gray valve, and then the black tank valve to equalize the tanks. If you open the gray first the gray water will back flow to the black tank. That way you don't get black tank crud into the gray.

Hope this helps

[TucsonJim]

I see Jim got the answer to you. On your unit do the gray and black tank drain plumbing connect and exit at one port? If so you when your boon docking and need more space in the gray tank you can add an external gate valve and be able to open the gray valve, and then the black tank valve to equalize the tanks. If you open the gray first the gray water will back flow to the black tank. That way you don't get black tank crud into the gray.

Hope this helps

I've seen people put an external valve on a single discharge pipe so they can share the contents of two gray tanks. But I've never seen someone share a gray and black. It appears that there are two separate discharge pipes on this unit for the two gray tanks. The real issue is that there is a totally unused 29 gallon storage tank if the washer is not being used. What a waste of great storage space.

Jim

[wootond]

Jim,

Thank you for the information on the tanks most helpful. Since I do not have a washer unit in my trailer, it makes sense to tie the 2 tanks together to have an additional 29 gallons of grey water storage.

Will do some research and let you know what I come up with. Again thank you all for the comments most helpful.

[Country Campers]

Jim,

Thank you for the information on the tanks most helpful. Since I do not have a washer unit in my trailer, it makes sense to tie the 2 tanks together to have an additional 29 gallons of grey water storage.

Will do some research and let you know what I come up with. Again thank you all for the comments most helpful.

I am not sure that you will be able to tie the 2 tanks together. The kitchen grey is in the rear and the washer grey is in the front. You would have to get pretty creative on some plumbing to attach the 2 , but could possibly be done. Good luck and let us know what you come up with.

Brian

[ThePowells]

wootond , Welcome to the forum and the family!!
My first thought is, and maybe the mods can answer, are the two gray tanks on the same level? If the W/D tank is lower, that helps. I would think that since you are wanting to move gray water, you could use a 1 inch flexible line and just be careful of any serious low points. You could connect in the vent pipes just above the tanks. The flexible line would be much easier to run.

I also noted this was your first thread, so when you get a chance check out the Welcome Letter to New Members https://gdrvowners.com/forum/main-fo...to-new-members

[Elaina]

Post#5 was most helpful to me, as I had realized the kitchen sink did not drain into #2 as I was told by dealer. Thank you Tucson Jim.

[howson]

Post#5 was most helpful to me, as I had realized the kitchen sink did not drain into #2 as I was told by dealer. Thank you Tucson Jim.

Glad TucsonJim was able to help! I'm only replying since I noted that was your first post. To get the most out of your time here on the forum, please check out the Welcome Letter to New Members https://gdrvowners.com/forum/main-fo...to-new-members

Howard

[Tom in PGH]

On your unit do the gray and black tank drain plumbing connect and exit at one port? If so you when your boon docking and need more space in the gray tank you can add an external gate valve and be able to open the gray valve, and then the black tank valve to equalize the tanks. If you open the gray first the gray water will back flow to the black tank. That way you don't get black tank crud into the gray.

Hope this helps

This could be a problem. The outcome of leveling/averaging the tanks will be dependent upon the level of liquids between the two tanks when you start. If the gray level is higher, relative to the black, the gray liquid should flow into the black. However, if the black is higher, you will have black flowing into the gray. Once they are level, in relation to one-another, the tank that becomes higher, either draining the sink or shower or flushing the toilet will, by gravity, flow into the other. Any time you flush, it will force some black to move into the gray. Any time you drain a sink, it will force gray into the black.

As a side-note, I don’t know that there would be an easy way to know the tank levels, relative to one another. You would almost need access to them, know what the level of the liquid is, inside, then evaluate if it would work. At any rate, after the initial leveling, I would close everything back up. If you didn’t, black will flow into the gray every time you flush the toilet. If you don’t mind a “black” gray tank, all of this may not be an issue, but I prefer to keep things separate. Also, keep in mind that you probably have a smaller discharge pipe for the gray system, so it could be a plugging problem if you get “black crud” in the smaller pipe.

[Guest]

Plumbing the two tanks together just before the gate valve drain will tie them together as the two tanks will eventually seek the same level. My two gray tanks are done this way in my Imagine from the factory. One valve for black and one valve for gray.

Can't imagine why GDRV would not utilize both tanks whether a washing machine was used or not.

Jim