2020 Momentum 25G Fresh water tank emptys

**rcarrell** · 09-14-2019, 04:10 PM

Originally Posted by 29roadster

I would like to route the vent line up to the fill port on the side of the trailer like my Starcraft. Just run it next to the fill hose. Then you can fill the tank completely, no way for it to siphon out

That's what I'm thinking of doing is going over and looking at my son's Outdoors RV Creekside and see if I can figure out how to do the fresh water like it with a gravity fill outlet since most of our camping is dry camping a should have gravity fill on it anyways. I know it works because I used to own it...LOL So yours has gravity fill I didn't know Grand Design put it on selected models.

**offtohavasu** · 09-16-2019, 09:16 AM

Originally Posted by boyscout

The outlet for the overflow is on the side of the tank below the top, leaving in a factory installation at least several thousand cubic inches of air at the top of the tank when it's filled to the overflow. Do you guys not think that air would sufficiently buffer altitude changes?

If not, I guess stopping occasionally during steep altitude changes to quickly open / close the valve to equalize pressure would.

Air is what is expanding and contracting...So no.

**offtohavasu** · 09-16-2019, 09:17 AM

Originally Posted by rcarrell

Okay, here's the deal , if Grand Design, in their infinite wisdom would have put a gravity fill on their trailers like everybody else, which in the case of my other RVs have had, they serve as the overflow as well as the fill when not hooked up to city water. My Momentum 25g has 2 fresh water tanks, supposedly 100 gallons, when they are full and its running out of both overflows it empties, and I measured it, 35 gallons on the ground. Now when I go down the road it will empty out all but enough water, that if we use as little as possible, I will run out in 2 days. That's going 100 miles to where we camp. This has happened 3 times before and after dealer repairs, or should I say non repairs and if you research this problem you will find Grand Design has had this issue for years. I'm at a loss to understand why they don't fix the problem when they're standing there with the water tanks and plumbing staring them in the face. I guess because they don't have to. I put a valve on mine yesterday and T'ed it so both overflows drain out of one line since I have to crawl under and between the axles to get at one of the drain tubes so I can use the trailer, which I haven't done much because of lack of water. I know I could of carried extra water but I kept hoping the dealer and Grand Design could fix it. Ha,Ha!! Don't get me wrong I like the trailer but stuff like this drives me to distraction. I think I'm going with bass mechanics fix unless I see something different because I have 2 tanks. Thanks again for all the replies and ideas.

Nooooooo, Grand Design is not the only company not using gravity fill. So the next question is, what are the other manufacturers doing? Same thing or...

**29roadster** · 09-16-2019, 10:01 AM

Originally Posted by rcarrell

That's what I'm thinking of doing is going over and looking at my son's Outdoors RV Creekside and see if I can figure out how to do the fresh water like it with a gravity fill outlet since most of our camping is dry camping a should have gravity fill on it anyways. I know it works because I used to own it...LOL So yours has gravity fill I didn't know Grand Design put it on selected models.

I like having a gravity fill, good way to add bleach to sanitize the tank and water system. Not sure how you would do otherwise. I can also fill the tank with containers of water if a hose is not available.

This is like mine. Vent is in lower left.

Link to one at Etrailer. https://www.etrailer.com/RV-Fresh-Wa...01-2003VP.html

Click image for larger version.

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**boyscout** · 09-16-2019, 01:42 PM

Originally Posted by offtohavasu

Air is what is expanding and contracting...So no.

Duh. Yeah, wisdom arrived sometime after I posted my question. Thx.

**offtohavasu** · 09-16-2019, 01:43 PM

Originally Posted by boyscout

Duh. Yeah, wisdom arrived sometime after I posted my question. Thx.

As Alf would say, "No problem!"

**offtohavasu** · 09-16-2019, 01:45 PM

Originally Posted by 29roadster

I like having a gravity fill, good way to add bleach to sanitize the tank and water system. Not sure how you would do otherwise. I can also fill the tank with containers of water if a hose is not available.

This is like mine. Vent is in lower left.

Link to one at Etrailer. https://www.etrailer.com/RV-Fresh-Wa...01-2003VP.html

Same way you fill the tanks from a bottle. You make a solution in a bottle, turn on the pump and let it fill the system. Even has a little diagram for "Sanitize" on the panel.

**29roadster** · 09-16-2019, 03:21 PM

Originally Posted by offtohavasu

Same way you fill the tanks from a bottle. You make a solution in a bottle, turn on the pump and let it fill the system. Even has a little diagram for "Sanitize" on the panel.

I like to put the chlorine/water mixture in the fresh water tank as well as thru the plumbing lines.

I have an Imagine 21BHE with a gravity fill so it may be different than other models.

On page 104 of the Imagine Operators Manual, it shows a Fresh Water Gravity Fill Inlet.

On page 105 under Sanitizing:
1. Turn winterizing valve back to open
2. Pour chlorine/water mixture into the "Fresh Tank Gravity Fill".
3. Turn ON water pump.
4. Open all faucet fixtures to circulate.

It sounds like some models don't have a gravity fill. Is the only way to fill the tank thru the Fresh Water Connection on the docking station in these?

**boyscout** · 09-17-2019, 08:08 AM

Originally Posted by 29roadster

It sounds like some models don't have a gravity fill. Is the only way to fill the tank thru the Fresh Water Connection on the docking station in these?

I've owned a Reflection and a Solitude - yes, the city water connection has been the only way to fill the fresh tank on both of them, no gravity feed.

**sgrol60** · 09-18-2019, 02:46 PM

I have tied my two fresh water dump lines together and run a PEX line from both dumps to the mid drivers side leveling jack. I can now bypass the nautilus system and fill the fresh water tanks from the bottom up. Can also shut the line and leave both dump valves open and pull water from both tanks at the same time. Never could figure out how GD plumbed the two tanks but I know the second tank doesn't fill until the first is full. And, I use the valves on the overflow vents as I lost my water supply one too many times too.