Gray water tanks advice

Talisker · 04-16-2018, 02:09 AM

Our 2018340 RL has two gray water tanks but tank 1 only connects to bathroom sink while shower and kitchen connect to tank 2. Looking at the pipes it appears to be an easy mod to connect the shower to the bathroom sink drain pipe thus “sharing” the tanks capacity between both tanks. Anyone done this or heard about it? Not sure designed the tank system but it would take us all summer to fill tank 1 with water from bathroom sink.

**piper guy** · 04-16-2018, 06:27 AM

Most of us add a Valterra Gate valve on the end of the sewer outlet. Then you can close that and open both grey valves and the tanks will self-equalize. Works like a champ.

RWJSIM2003 · 04-16-2018, 07:12 PM

We have done the same as Vaughn described above and it works great on our gray tanks.

https://www.amazon.com/Valterra-T58-...rra+gate+valve

Talisker · 04-16-2018, 09:43 PM

Thanks for the advice. Picked one up this morning in Page and will see how it works.

xtasee · 04-17-2018, 12:22 AM

I have the Wastemaster Cam lock system. I swear someone on here once had a link for a valve that would work at the drainpipe end for this system. I would like to install a valve without attaching the hose. The idea behind this is that when boon docking in the mountains I want to do the two holding tank thing then hook the hose up later when getting to the dump.

If someone has found a cam-lock valve without doing a cam-lock/twist-lock adapter then the valve I would appreciate the link. I thought it was at Drainmaster but could not find it.

mhs4771 · 04-17-2018, 01:27 AM

Larry, I don't have the Cam Lock system, but I actually cut the main drain line where it exits from the Drop Frame section and installed a valve there and don't have to worry that an external one might come off during travel. Works for me, especially since I have a Galley valve that doesn't always close all the way.

xtasee · 04-17-2018, 04:10 PM

Quote:

Originally Posted by mhs4771

Larry, I don't have the Cam Lock system, but I actually cut the main drain line where it exits from the Drop Frame section and installed a valve there and don't have to worry that an external one might come off during travel. Works for me, especially since I have a Galley valve that doesn't always close all the way.

That makes total sense! After reading several other posts related to this, I think most of us have the 3 cups of grey water drainage issue when opening the cap. Your solution would take care of both issues at the same time.

The only other thing would be to test the system to see if I am actually able to use both holding tanks first. Having the 31SL could be different.

Thanks so much for the alternative idea!

mhs4771 · 04-17-2018, 04:34 PM

I know it's different on the MB, as our Gray tank is in the drop frame section, while the Galley is above the axles so our Galley would tend to flow into the Gray filling it first.

Talisker · 04-19-2018, 02:08 AM

I installed the Valterra gate valve; opened both gray tank valves and voila, the two tanks equalized. Excellent advice form the veterans out there. Much appreciated!

RollsRoyce · 06-05-2018, 05:04 AM

Any pictures or videos on this system change?

wekirby · 06-09-2018, 05:19 PM

Quote:

Originally Posted by piper guy

Most of us add a Valterra Gate valve on the end of the sewer outlet. Then you can close that and open both grey valves and the tanks will self-equalize. Works like a champ.

Hi!
I have the same issue. How and where do you install that valve please?
Thank you!

atom ant · 06-09-2018, 06:48 PM

You install it on the discharge. That way you can close it, and then open the two gray tanks.

I normall just left it on, and stored the elbow and rubber grommet there as well. Called it my VTOL booster

It doesn't work on all models - as the tanks have to be level with each other. If they are stacked, it makes it worse because the bottom tank will fill up faster than it normally would because it is taking water intended for both tanks.

mhs4771 · 06-10-2018, 03:17 AM

I went a step further and cut the main discharge line where it exits the Drop Frame assembly, installed a knife valve there, and then attached the OEM section of pipe to that valve. Don't have to worry about the possibility of an external valve coming off going down the road.

wekirby · 06-16-2018, 02:24 PM

Hi!
Sorry if I'm a little daft, but when you open the 2 gray tanks, do they backfill each other or how do they both fill evevnly?
Thanks for the photo too!
Wekirby

johnboytoo · 06-16-2018, 02:40 PM

Water seeks it's own level, so as liquids go into one tank, gravity will push some of it into the other tank (IF the tanks are level as Brad stated)

Just remember which order to open and close

I did this on our 5'er and can do it on the motorhome since Momma takes LONG showers

if the rv is not too low to the ground when dumping air

Highcountrybarry · 06-16-2018, 06:33 PM

Caution, make sure your tanks are both on the same level or the highest will fill (read overfill) the lowest.

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COLJDM · 06-24-2018, 01:49 PM

Larry, I agree with Vaughn and Michelle. We have a sewer boom on our 2012 36FL and I cut the line and installed the valve. Works great. I can't understand why Redwood takes 45gal of grey capacity and only makes it available for the clothes washer, which is used once or twice a week, if you have one. That tank should handle the shower/bathroom and washer and the other grey tank should handle the kitchen. When I get a few extra dollars I still might have my local RV shop change the plumbing, however, it is not high on my priority list.

travelin' texans · 06-24-2018, 05:08 PM

Quote:

Originally Posted by COLJDM

Larry, I agree with Vaughn and Michelle. We have a sewer boom on our 2012 36FL and I cut the line and installed the valve. Works great. I can't understand why Redwood takes 45gal of grey capacity and only makes it available for the clothes washer, which is used once or twice a week, if you have one. That tank should handle the shower/bathroom and washer and the other grey tank should handle the kitchen. When I get a few extra dollars I still might have my local RV shop change the plumbing, however, it is not high on my priority list.

Mine is set up that way, shower, washer, & lavatory in one tank & galley in the other & have the same problem, the bath tank is always full. If hooked up to sewer I leave the bath grey valve open otherwise I'm draining every other day. We have the W/D & it gets desde 3-4 times a week.

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