Newbie Questions on grey tanks

Kudu19 · 03-22-2021, 09:53 PM

Hi everyone,
We recently got an 8336BH bunkhouse with 4 tanks they each has its own dump valve... 2 Grey, 1 Galley and 1 Black. The 2 Grey and 1 Black are in the same location, the galley one is more in the back.
We've been camping a couple of times with it now and the first time we went we tested and filled about 3/4 all the tanks, mostly to test the sensors, or so I think I did maybe?
This last trip the Grey tank #2 didn't fill up when #1 overflowed a bit as I noticed from the bathroom sink as i was using it.
I thought it was automatic for each grey tank to switch from one to the other when the first one fills up.
Did i miss a switch maybe?

Any idea why #2 didn't start filling when #1 filled up completely?

Thank you all in advance!

NavyLCDR · 03-22-2021, 10:16 PM

Just a guess here, but I'll bet the grey tank #2 is for a washing machine only and is completely separate from grey tank #1 which is for bathroom sink and shower.

Kudu19 · 03-22-2021, 10:29 PM

Quote:

Originally Posted by NavyLCDR

Just a guess here, but I'll bet the grey tank #2 is for a washing machine only and is completely separate from grey tank #1 which is for bathroom sink and shower.

And you are probably right! There's a hook up for a washer/dryer too on the RV. Probably that's what it is then. Thanks!

dalford · 03-22-2021, 10:54 PM

Also, I don’t think you missed a switch. Most tanks grey or black are plumbed separate. They don’t automatically fill when one is full. FYI, galley is grey also. So looks like you have 3 grey tanks and 1 black tank....

ARhappycamper · 03-22-2021, 11:42 PM

Pretty sure that camper has 2 gray tanks, 1 black tank, and 1 fresh water tank. The kitchen sink is on 1 grey tank. Shower and bathroom sink on the other.

dalford · 03-22-2021, 11:47 PM

Quote:

Originally Posted by ARhappycamper

Pretty sure that camper has 2 gray tanks, 1 black tank, and 1 fresh water tank. The kitchen sink is on 1 grey tank. Shower and bathroom sink on the other.

Just going by his op that he has 4 valves..freshwater does not have a valve...your scenario matches what I have but I certainly don’t know all the different set ups on RVs... hopefully the op will come back and clarify

Kudu19 · 03-23-2021, 12:19 AM

Quote:

Originally Posted by dalford

Just going by his op that he has 4 valves..freshwater does not have a valve...your scenario matches what I have but I certainly don’t know all the different set ups on RVs... hopefully the op will come back and clarify

Correct, i have 4 valves plus the freshwater tank. 1 grey valve is in the back and labeled "galley tank", so i assume it's for just the one kitchen sink, then i have two more Grey valves and 1 Black one coming out of 3/4 to the front, under the bathroom area, of these, one valve labeled "Grey Tank #2", one labeled "Black Tank" the other grey valve (that works) had no label, but i know it's #1 from emptying and verifying the inside control panel. In addition there a fresh water tank with its own flushing outlet all the way in the rear under the outside kitchen (no sink).

dalford · 03-23-2021, 12:35 AM

Quote:

Originally Posted by Kudu19

Correct, i have 4 valves plus the freshwater tank. 1 grey valve is in the back and labeled "galley tank", so i assume it's for just the one kitchen sink, then i have two more Grey valves and 1 Black one coming out of 3/4 to the front, under the bathroom area, of these, one valve labeled "Grey Tank #2", one labeled "Black Tank" the other grey valve (that works) had no label, but i know it's #1 from emptying and verifying the inside control panel. In addition there a fresh water tank with its own flushing outlet all the way in the rear under the outside kitchen (no sink).

Thanks for clarifying your tank setup. One f your original questions was about the tank filling and not automatically overflowing to another tank. I’ve never heard of this and usually all tanks are plumbed separately.

I assume all the tanks empty out one outlet? If that is the case some folks add one of these to that outlet and then can open two grey tanks and let the share the grey water. If one fills and another is not then if you added this extra valve you can do this without grey water spilling out when you remove the sewer cap.

It is also just good practice to add one of these as there are times when a valve may not seat correctly. Nothing worse than removing that cap and black or grey water gushes out..

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Kudu19 · 03-23-2021, 12:50 AM

Quote:

Originally Posted by dalford

Thanks for clarifying your tank setup. One f your original questions was about the tank filling and not automatically overflowing to another tank. I’ve never heard of this and usually all tanks are plumbed separately.

I assume all the tanks empty out one outlet? If that is the case some folks add one of these to that outlet and then can open two grey tanks and let the share the grey water. If one fills and another is not then if you added this extra valve you can do this without grey water spilling out when you remove the sewer cap.

It is also just good practice to add one of these as there are times when a valve may not seat correctly. Nothing worse than removing that cap and black or grey water gushes out..

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Fantastic thank you! That's exactly what I was looking for. I was going to buy that add-on valve to avoid messes but now I see how it can help me maximize the use of both my grey tanks. Much appreciated, love this community, everyone always so helpful, here and at the campgrounds

ARhappycamper · 03-23-2021, 05:34 AM

Quote:

Originally Posted by dalford

Just going by his op that he has 4 valves..freshwater does not have a valve...your scenario matches what I have but I certainly don’t know all the different set ups on RVs... hopefully the op will come back and clarify

Well my freshwater tank has a dump valve !

dalford · 03-23-2021, 02:15 PM

Quote:

Originally Posted by ARhappycamper

Well my freshwater tank has a dump valve !

Going to start calling you lucky...lol.. I did not know fresh water tanks have knife blade valves like the the sewer and grey valves. Mine has a small 45 degree twist valve under RV but not a knife blade valve. Learn something new on this forum everyday. I wish it did have a large dump valve like yours...trink39:

CHICKDOE · 03-23-2021, 02:59 PM

We have two grey tanks but 1 is dedicated to the washer that we don’t have. This may be similar to your setup. We use that screw on valterra valve at the sewer hose connection. Close the screw on valve and open the two grey valves. This will connect the two grey tanks and give you increased grey tank capacity. Keep the black tank valve closed while you do this.

To drain the tanks close the two grey tank valves. Then open the twist on valve and it will drain the grey water in the connecting pipes. The proceed as normal. Drain black the the greys.

llr · 03-23-2021, 03:10 PM

Quote:

Originally Posted by dalford

Going to start calling you lucky...lol.. I did not know fresh water tanks have knife blade valves like the the sewer and grey valves. Mine has a small 45 degree twist valve under RV but not a knife blade valve. Learn something new on this forum everyday. I wish it did have a large dump valve like yours...trink39:

I didn't know any Forest river products had this but I know Grand Design does. Slightly smaller, I believe 2".

I agree those small almost drip drains are a pain.

**bikendan** · 03-23-2021, 03:28 PM

Quote:

Originally Posted by ARhappycamper

Well my freshwater tank has a dump valve !

Please provide a pic of that. I've never heard of any Rockwood with this.

KEN9XL · 03-23-2021, 04:39 PM

Quote:

Originally Posted by Kudu19

Fantastic thank you! That's exactly what I was looking for. I was going to buy that add-on valve to avoid messes but now I see how it can help me maximize the use of both my grey tanks. Much appreciated, love this community, everyone always so helpful, here and at the campgrounds

You have the same set up as myself. (4 levers, 3 grey & 1 black)
One grey is at the rear and two at center with black tank.

The two grey tanks Do Not Overflow into one another. Nice thought!

My rear grey tank goes only to the outside kitchen sink.
The two grey tanks at center split. One is for the interior kitchen only and the other is for the bathroom sink & shower. The black tank goes to the bathroom toilet, but I understand that is not true in all models. Puzzling!

Good Luck - Stay Safe
Happy Camping

ARhappycamper · 03-23-2021, 10:19 PM

Quote:

Originally Posted by bikendan

Please provide a pic of that. I've never heard of any Rockwood with this.

Is that just a sneaky way of calling me a liar ?

**bikendan** · 03-23-2021, 11:24 PM

Quote:

Originally Posted by ARhappycamper

Is that just a sneaky way of calling me a liar ?

Nope, would like to see what changes Rockwood is making since I used to own a Rockwood.
I think Rockwood/Flagstaff make the best trailers for the pricepoint.

phurth · 03-26-2021, 06:28 PM

We currently have the 8336BH on order and I had asked Forest River about the tanks. Here's their response:

Black 1 (Toilet) - 50 gal
Gray 1 (Shower, Lav) - 50 gal
Gray 2 (Washer) - 40 gal
Galley (Kitchen) - 40 gal

We plan on doing the blade valve trick to combine the washer and bathroom gray tanks for longer trips. A total of 130 gallons of gray capacity is pretty cool even if it's not all one tank.

CHICKDOE · 03-26-2021, 06:52 PM

that only works if the tanks drain out a common sewer connection. i'm not sure that all four tanks will drain out a common sewer connection. you need to find out how many actual sewer hose connections you will have and what tank drains into each sewer connection.

phurth · 03-26-2021, 07:04 PM

Quote:

Originally Posted by CHICKDOE

that only works if the tanks drain out a common sewer connection. i'm not sure that all four tanks will drain out a common sewer connection. you need to find out how many actual sewer hose connections you will have and what tank drains into each sewer connection.

Yep - on the 8336BH, the 2 forward gray tanks drain out a common outlet with the black tank. The 3rd gray tank is by itself toward the rear. At least that's what Forest River indicates.

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