Grey Tanks 1 & 2

[jgshake]

Hi All,
We are in our newly purchased 2016 337RLS for our first trip and are loving it so far. We were told that we have 2 grey tanks and they are labeled 1 & 2 on the control panel. How do we know which is for the bathroom and which is for the kitchen? I've looked all through the owner's manual and online but can't find that info anywhere.
Thanks!

[Cate&Rob]

Usually the kitchen gate valve is 2" and the bathroom gate valve is 4", so the bathroom handle pulls out farther than the kitchen handle. To be sure, drain both tanks and close the valves. Now, run the kitchen tap for a while or have a shower (not both ) and then see which gate valve releases water.

Rob

[JCZhome]

I don't have that model and I'm not sure which is which......on my 376TH they both come down the same pipe. I've always drained both at the same time. But one way would be to drain one of the tanks and leave the drain open. When it's empty and no longer draining, then turn on the water in your kitchen sink and see if it starts to drain again.

EDIT: I see Rob was replying at the same time that I was. My gates are above the coroplast and so I'm not able to see either valve.

[Greene728]

I did the above. When empty, close them off and I ran the kitchen faucet for about 10-15 min then opened one at a time till I got a good clear flow of water. If I remember correctly on my 303 number 1 was bath and 2 kitchen. After I figured it out I labeled them.

[jgshake]

Thank you all, very helpful, we'll use your suggestions and figure it out!

[memphisflyer]

FWIW, on my 384GK they go front to back numerically. Number 1 grey is forward (bathroom for us) and number 2 grey is aft which is our kitchen. I don’t know if front to back is a standard GD practice.


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[jgshake]

My husband also contacted Grand Design, they say that the bath is most likely #1 which matches what you said, memphisflyer. Also the kitchen holds 32 gallons and bath is 43 gallons. We're laughing because we got responses much faster from this Forum than from Grand Design, although they did respond quickly LOL. Thanks again!

[Second Chance]

Many of us who have two gray tanks (those on our 2016 337 are of equal size) have put an external gate valve (Valtera makes a good one - you can order it from Amazon) at the end of the waste water drain outside. With the black tank valve closed, we keep this external gate valve closed and both gray tanks open. This way, we don't have to worry about which gray tank fills up first - we have a combined capacity of 70 gallons (plus a couple of gallons for what's in the lower drain). When it comes time to drain tanks, I close the gray tanks, open the lower gate valve, and open the black tank to drain (along with turning on the flusher). When the black tank is empty, I close that and open the gray tank valves to drain the gray tanks and flush everything out. When everything is empty, I set things up as originally described (lower gate valve and black tank closed, gray tank valves open). The only time I vary this is when there's going to be a deep freeze. I then close all the OEM valves and drain the lower pipe(s) so the part that's outside the underbelly won't freeze and crack.

Rob

[gordofuchs]

Many of us who have two gray tanks (those on our 2016 337 are of equal size) have put an external gate valve (Valtera makes a good one - you can order it from Amazon) at the end of the waste water drain outside. With the black tank valve closed, we keep this external gate valve closed and both gray tanks open. This way, we don't have to worry about which gray tank fills up first - we have a combined capacity of 70 gallons (plus a couple of gallons for what's in the lower drain). When it comes time to drain tanks, I close the gray tanks, open the lower gate valve, and open the black tank to drain (along with turning on the flusher). When the black tank is empty, I close that and open the gray tank valves to drain the gray tanks and flush everything out. When everything is empty, I set things up as originally described (lower gate valve and black tank closed, gray tank valves open). The only time I vary this is when there's going to be a deep freeze. I then close all the OEM valves and drain the lower pipe(s) so the part that's outside the underbelly won't freeze and crack.

Rob

We do the exact same as above and have found this to work out very well. Prior to installing the external gate valve, the two tanks filled up at an unequal rate, which made for complicated dumping. When you couple that with the unreliability of the gages, it's too much of a guessing game of when to dump.

[Canyonlight]

jgshake - sounds like you got the information needed with regards to matching tank pull handles and which tank it is along with some other good points.

Another tidbit, with the 337 and with our 303 tanks and dump gate valves layout, emptying your kitchen sink tank last will help to clean any residue in the sewer pipe from the black tank. See post #50 from Patrick with drawing of tanks/valves/pipe showing why this would be the case: https://www.mygrandrv.com/fo...highlight=gate

Post #5 from Ben in this link has pictures of the three tanks from his 293 (same tanks/locations/etc. as 303/337/others) with valves/pipes/etc.: https://www.mygrandrv.com/fo...=holding+tanks

Dan