2015 38RL - Grey Water Tank Size?

[BasilFawlty]

The Galley Grey tank fills up much faster than the Shower Grey tank.

I read the manual but could not find the actual tank size.

Redwoods homepage says "90 Gallons Grey Water".

Does anyone know if they both are 45 Gallons each?

[piper guy]

They are 45 gallons each. Best way to equalize them is to add a valve at the outlet and then you can close that valve and open both grey valves and they will equalize.

[BasilFawlty]

Thanks for the fast answer! We have a back flush valve to flush out the grey tanks and the galley tank seems to fill much faster. Most likely just dirty sensors then if they are equal in size.

[Rick and Mindy]

They are 45 gallons each but the way Redwood hooked mine up just doesn't make sense. That's why we purchased the additional slide valve to allow us to open both gray tanks so they will equalize. On my 31SL, all the water from the kitchen and shower go into one tank and only the bathroom sink goes into the other. Doesn't make sense as it takes a long time to fill up the tank with only the bathroom sink and the other one will fill fast with everything else going into it.

[piper guy]

The 36RL is the same way. The other tank is set up for the Washer Dryer and the bathroom sink. Definitely add the slide valve on the end to equalize the tanks.

[brenkco]

This method of installing a valve at the sewer exit apparently works on some but not all models. I tried it on my 38gk. The galley tank is mounted below the grey tank. Once the galley tank is full, water backs up and leaks from the ptraps into the belly. Unfortunately it doesn't back fill into the grey tank on my model. I sure wish it did as it would be helpful when boondocking.

Ken

[Bill n Diana]

Ken,

What model RW do you have???

I am considering this with my 38FL.

Bill n Diana

[Rick and Mindy]

Originally Posted by brenkco

This method of installing a valve at the sewer exit apparently works on some but not all models. I tried it on my 38gk. The galley tank is mounted below the grey tank. Once the galley tank is full, water backs up and leaks from the ptraps into the belly. Unfortunately it doesn't back fill into the grey tank on my model. I sure wish it did as it would be helpful when boondocking.

Ken

Ken, help me out here. In my mind I'm trying to understand why your gray water will not back fill into the gray tank once the galley tank is full. I'm no plumber but your p traps have to be higher than both tanks. If you have both gray tank valves open and the sewer exit valve closed then I would think the gray tank would start to fill before the water can get high enough to get back into the p traps. Maybe it's just too early in the morning to be trying to think this out!

[brenkco]

Bill & Diana, I have a 2014 38GK. I'd sure give it a try to see if it works for you.

Rick and Mindy,
Not exactly sure why but I tested it a few times with the same results.

I'm really only guessing at the location of the leak as I was not able to actually find it, I just observed the results. Closing the valve at the sewer exit, I let the galley tank fill. The source for our galley tank is the shower, kitchen sink including dishwasher.

When full, it leaked all through the belly pan and on to the ground. My assumption that it was the trap maybe incorrect as I have tested it by filling the galley tank with the galley tank valve closed. This resulted in the water backing up into the shower. I may have not let it sit long enough for it to have leaked in the traps. The only other place it could be leaking is through the vent pipe. My black tank had failed (and was replaced) due to a bad spin weld on the vent pipe. When the black tank was full, it leaked around the vent pipe spin weld and leaked through the belly pan.

I am also assuming that the galley tank is mounted lower than the grey tank. Water going up hill may contribute to the problem. Before the RV's came out with the drop frame, the grey and galley tanks were at the same level, thus the solution of using the end valve and opening both tanks worked. It sure doesn't for my rig.

In any event, when we try to back the galley tank into the grey tank, we have a mess! We really hoped this would work for us too as it's a shame to have a empty grey tank when boon docking!!

Ken

[Rick and Mindy]

Ken, sorry to hear that this system doesn't seem to work for you. I don't want to be repetitive but you don't say that you leave both gray water valves open. I just want to make sure that that is what you are doing. My thought is that if it only leaks when you use the exit valve then the leak is occurring somewhere from the drain line of the tank to the exit valve because you say the tank doesn't leak when you keep the galley valve closed. Have you tried filling the other gray tank while leaving it's valve open and the exit valve closed? That would tell you if the leak is occurring from the gray valve to the exit valve and not from the tank up to the traps. Just trying to think of all possibilities.

[brenkco]

No Rick, both tank valves were open, only the exit valve was closed. Some waste water did back up into the grey tank but a majority leaked.


I can only assume that the pressure is causing leaks due to water trying to run up hill.


Ken

[Rick and Mindy]

Originally Posted by brenkco

No Rick, both tank valves were open, only the exit valve was closed. Some waste water did back up into the grey tank but a majority leaked.


I can only assume that the pressure is causing leaks due to water trying to run up hill.


Ken

Ok Ken, I give up. Maybe someone else on this forum may have suggestions. Again, I know your frustration in not being able to utilize the total 90 gallons when you need it. That extra 45 gallons can make the difference in dumping every other day to once every 5 or 6 days.

[brenkco]

Thanks for your thoughts, Rick.


I have tried a few posts some time ago on this and the other forum. Not sure that there is much else that can be done...kinda one of those oh well.....and live with it!!


Ken

[Bill n Diana]

In reading through this whole string the only thing that I can think of given everyone's great input is that there is a joint that is not completely sealed between the two gate/knife valves.

Normally the stretch of drain pipe between the gate/knife valve does not have to hold water... the drain water runs through it but it does not hold water for any real period of time... When we add another valve at the end to make use of both holding tanks we now have more pipe that must be waterproof / sealed completely...

The kicker to all of this is finding where that one(?) spot might be that needs to be completely sealed... I am not sure I would ever consider undertaking that task given what is involved in gaining visibility to those underbelly areas... And I am not sure that all dealers would voluntarily do this work when we are using this system beyond its intended purpose...

Don't get me wrong, I think the manuafacuturer should have ensured that all joints were completely sealed; but I am also confident that they would not have added another gate/knife valve to test those seams below the original valves.

At some point we all have to determine whether the juice is worth the squeeze.

Happy Travels,

Bill n Diana

[mhs4771]

Ditto, Bill must have read my mind (a really short story) and beat me to the post.

[brenkco]

Originally Posted by Bill n Diana

And I am not sure that all dealers would voluntarily do this work when we are using this system beyond its intended purpose...

Bill n Diana

Bill,

This we can agree on as I tried. Truly beyond it's intended purpose! However, I have disproven your theory about the two valves. I regularly open both the grey tank valves and just use the secondary valve to dump the tanks when parked for a while.....no leaks whatsoever. Therefore, one can conclude that the drains from the factory valves to the secondary exit valve is secure.

I am currently traveling with a bunch of Montana owners, some of which have the old style frames where the tanks are mounted at the same horizontal level. The tanks equalize perfectly.

The consensus of this group is that drain pipes are not intended to take pressure. The full lower tank combined with the upper tank creating gravity feed pressure applies enough force not contemplated by the drains. I still suspect that it is probably the spin weld on the vent pipe of the galley tank......

But as you eloquently said,

Originally Posted by Bill n Diana

At some point we all have to determine whether the juice is worth the squeeze.


Bill n Diana

Thanks for your feed back and assist!

Ken

[Bill n Diana]

Ken,

While I thought there might be two different levels the tanks sat I didn't know as my 38FL has all the tanks at a single level...

As Sheldon Cooper once said, "Gravity..., thou art a heartless biotch..."

Happy Travels.

Bill n Diana

[atom ant]

Ken,
I would agree, it sounds like the vent collar - those are not very tight secure connections, and probably not worth pushing your luck. I think the collar is just glued on the tank.


Everything is a trade off on RV design and features for sure.