3761 Grey Tank - Montana Owners Club

bwright · 07-06-2021, 08:20 PM

We have a brand new 3761 and the Grey 1 tank, kitchen sink and 1/2 bath, appears to fill up quickly. Anyone know how big this tank is?

RMcNeal · 07-07-2021, 04:00 AM

I have a 3791RD. Our grey tanks are 44 gallons each. I assume yours would be the same? Specs on Keystone's site says 88 gallons grey water and88 gallons waste water so I guess you also have 2 black tanks?
Other than flushing it, I don't think I have ever completely filled my grey galley tank, but I don't have a 1/2 bath either. That seems like a lot of water from just a couple sinks. Do you have a washer/dryer?

**DQDick** · 07-07-2021, 05:56 PM

If you do have a washer/dryer you will have to dump the tank it drains into frequently. Two wash loads and ours is completely full w;ithout much of anything else.

bwright · 07-07-2021, 06:04 PM

No washer/dryer. Could it be a clogged vent? If I drain the tank, the sink drains too. In no way was there 44 gals in the grey tank when it stops up and like I said, this is a brand new unit, second trip out.

Mikendebbie · 07-07-2021, 06:06 PM

Question on washer and dryers and the gray tank…I generally leave the gray tanks open in camp. We are getting a washer and dryer next week. With the washer - do you leave the gray tank open? If not - why?

RMcNeal · 07-08-2021, 04:07 AM

Mike, I don't have the washer/dryer yet, but I would definitely leave the the gray tank open when washing, if on full hookups, for two reasons. 1. I'm not sure to which tank the washer is plumbed. I have heard of some that are straight to the drain itself, not going into a tank. 2. Why not? There's no reason to store that water if I have full hookups. I usually keep them closed near the end of the trip to use shower water to flush the black tank, but I don't want anything backing up during the washing cycle.

RMcNeal · 07-08-2021, 04:10 AM

Quote:

Originally Posted by bwright

No washer/dryer. Could it be a clogged vent? If I drain the tank, the sink drains too. In no way was there 44 gals in the grey tank when it stops up and like I said, this is a brand new unit, second trip out.

A clogged vent would make the drain slow, but it shouldn't back things up. If you fill your sink, then pull the stopper, does it gurgle and drain into the tank slowly, or just drain normally. The gurgling and slow drain could indicate the vent is blocked. The easiest way to check is to get on the roof with a water hose and run it down into the grey tank. Could be a critter nest in the pipe or something, I suppose.

DutchmenSport · 07-08-2021, 11:32 AM

As stated above, according to Keystone's web site, you probably have 44 gallon tanks.

Are you hooked up to city water and running water in the camper from the garden hose, or are you running water from your fresh water tank via your on-board water pump?

If you are using water straight from the garden hose, then you are most likely using much more water than you realize and the tanks are simply filling up. If you forced yourself to run you water from your fresh water tank, you'll learn and be able to track much easier how much water you are actually using.

I've run many, many tests on my Montana attempting to figure out how much water is actually being used, and where.

It turns out, the highest water volume consumption is the kitchen sink. We use twice as much water in the kitchen sink (grey tank) than we do in the shower and bathroom sink, and that's for 2 people.

Second highest usage is the bathroom shower and sink, which uses about twice as much or more than the black tank.

How do I know this? First I fill my fresh water tank full. I know how much it holds. Then I dump my tanks into a Blue Tote. We very, very seldom camp with full hook-ups. We (sometimes) have water on site, but very, very seldom do we have sewer hook-ups. When we do, it's really a treat!

So, I can calculate how much water is being used by the amount being dumped into the blue tote to hall to the dump station.

If the black tank (1 toilet only) = 1
The shower and bathroom sink = 2
The kitchen sink = 4

Now that we have installed a washing machine and dryer (Splendid stackable), I've measured .... very carefully ... how much discharge is coming out of the bathroom grey tank for a given load of wash. It's slightly more than 8 gallons of water.

Well, that changes the usage. Bathroom shower-sink-washing machine is the highest usage. On that same scale, as often as we do laundry, that puts the bathroom grey tank at about 16.

That's right. For ever 1 gallon of water in the toilet, there is 16 gallons of water going into the bathroom grey tank, and the kitchen is still 4 gallons. When you have a 50 gallon fresh water tank and you monitor it for fill ups and catch your sewage as you discard it, you learn real fast, that Navy showers are still a must.

I think you are simply using more water than you realize. It's just that simple.

Now, about leaving those tanks open....

Do an experiment. Wash dishes in your kitchen sink. When you are done, pull the drain and let it drain completely out. What happens? The water drains and takes most of solids with it. But it still leaves behind streaks of grease, BBQ sauce, spaghetti sauce, crumbs, bits of noodles, bits of corn, bits of carrots, bits of meat that stick to the sink.

If that stuff sticks to the sink and you've pulled the plug and let the water "swoosh" out.... um ... how much of the stuff is sticking to the bottom of your kitchen grey water tank when it doesn't have water to "swoosh" it on down. Unlike a 2 inch pipe in your house where tons and tons of water push everything down a very narrow passage, the bottom of your grey tank is pretty flat! All that stuff that goes down there, will stick down there too! The more water you have in the tank to flush it out, the more likely you'll get that crud out of there.

We are able to dump our tanks on the ground at home. We have a septic system, so the black tank always goes into the septic tank, but the grey water in both the kitchen and bathroom often get dumped on the ground. And believe me .... if you've ever dumped your kitchen water on the ground.... IT STINKS! I quit dumping the kitchen water on the ground for this very reason. The crud that stick inside the tanks is worse than you think.

lewy64 · 07-14-2021, 01:31 PM

I have a 2019 3761 and have a washer and dryer. My setup is this - kitchen sink = grey 1, half bath sink and toilet + washer drain = black 1, shower and main sinks grey 2, main bath toilet = black 2. Now that does not mean that yours will be the same I have heard the half sink and the washer drain being switched to main sink. It all depends on the installers mood that day.

When you wash immediatly open that tank it goes into, you dont want to forget and do what i did, flood the kitchen area. I have a smaller load machine and 2 washes is definitely too much. I put a picture of my drain levers and noted what to open when washing, on the washer itself as a reminder.

I also have a Reverse Osmosis on the kitchen sink and leave that one open always, except when dumping, Will have to fill it up and flush on occasion.

I am fultiming so the reason for the RO. I also run a portable water softener in the water closet (the new meaning not the old).

oh thats right it is called the convenience center

oh here is link to the brochures with all the info - https://www.keystonerv.com/brochures

BuckandTeresa · 07-14-2021, 02:20 PM

We have a 2019 MHC 330RL. We had ours installed before delivery by the dealer. Disaster! They left the high pressure water lines not even finger tight, leaked all down through the trailer bottom and out the crack between the sheet metal pieces. Luckily, no water damage I can find. The dealer also dented the front of the dryer during install and had to force them to replace it with another new one. All my sink drains and water connections and black tank flush airlock were less than finger tight and leaked. Make sure you check all this thoroughly.

We are really glad to have the washer dryer!

When we plan on using the washer on a trip, I always open the gray #1 tank drain. It will fill up pretty rapidly, and my bathroom sinks and shower fill this same tank, I think. I think the Gray#2 tank is only for the kitchen sink. I usually leave that closed to help after-flush the main drain line after I drain the black tank.

ShaneGreen · 07-14-2021, 05:37 PM

2018 331RL and our washing machine is in the bedroom closet / front cap. It drains to the bathroom sink & shower gray tank. So I got busy and forgot to pull the valve on that tank and we did two loads of laundry. By the 3rd load the tank was full and started backing up. I would have thought it would back up into the shower, but apparently there is some sort of back-flow valve on there. Instead, it backed up to the laundry service panel, ran down the inside of the cap and filled the area above the pinbox.

Had soapy water pouring out of every seam under the cap. Lots of fun to open it up and dry it all out.

More fun a month later when someone who shall not be named put way to much detergent in the machine. Bubbles need a way out. They decided the dryer vent was the quickest path to freedom (it's a combo unit). Ended up with a giant mound of linty bubbles in my lawn chair.

CaptnJohn · 07-14-2021, 06:21 PM

I have a 3761 FL and installed a washer and a dryer. Washer drains into the half bath black tank with the toilet and sink. Only a 44 gallon tank.

Tom0329 · 07-14-2021, 07:10 PM

Quote:

Originally Posted by Mikendebbie

Question on washer and dryers and the gray tank…I generally leave the gray tanks open in camp. We are getting a washer and dryer next week. With the washer - do you leave the gray tank open? If not - why?

When we are doing laundry I open the rear gray tank. I close it afterwards so I have gray water to flush the hose after I dump the 2 block tanks.

mhs4771 · 07-14-2021, 07:18 PM

I was leaving the Gray open one Winter and ended up the a Cockroach making a home in our Washer. I have to believe that he came up through the drain line, but then couldn't get out of the Washer until I finally caught and killed him. Don't leave any valves open any more.

Montana Bob · 12-29-2021, 06:44 PM

I know it is late to the party,but we are having the same problems with our 3761FL. OP,did you fix it?

Mikendebbie · 12-29-2021, 08:03 PM

Quote:

Originally Posted by Mikendebbie

Question on washer and dryers and the gray tank…I generally leave the gray tanks open in camp. We are getting a washer and dryer next week. With the washer - do you leave the gray tank open? If not - why?

Our washer is plumbed to the front black tank. I leave valves closed until we have run a couple of loads - then dump the tank.

bwright · 12-29-2021, 08:14 PM

I was never able to get the Dealer to get a fix from Keystone, however, it burped on me one day and I believe it fixed itself

Tree Top Turkeys · 01-02-2022, 12:58 PM

Wonder if Keystone ever considered installing a cross over pipe from both gray tanks. That way if one filled quicker it would balance the capacity

RMcNeal · 01-02-2022, 01:38 PM

I doubt it. You. An accomplish that with a twist on valve at the outlet though. Close the outlet and open both gray tanks to balance them out somewhat.

mhs4771 · 01-02-2022, 03:13 PM

All depends on the locations of the two Gray tanks. Our Bath/Laundry tank is in the Drop Down frame section next to the Black, our Galley is above the axles, at least a 10 inch difference. So if we tried that everything from the Galley would flow into the Bath/Laundry tank, with no way to push water uphill into the Galley tank.

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