Fresh Water Tank Capacity 297RSTS 2021

[DavidBarnes792]

Thank you for the feedback. Yes, I used a "hose end" meter to measure the capacity of the fresh water tank. I checked the acuracy of the meter and it's right on. I do have a tank style water heater so I suppose I have to add that 6 gallons to the capacity, which is still only 37. I will use the fresh water tank until it runs dry and just carry a couple of jerry cans as a backup. Adapt and overcome.

[howson]

I understand that we lose a few gallons bc of the overflow, but this is ridiculous... I own an Imagine XLS 22MLE and discovered today that the 47 gallon fresh water tank will only hold 31 gallons. 16 gallons short of the stated capacity?? If any other members have the same model I am interested to know if this is normal for the 47 gallon tank.

The specs on the 22MLE on Grand Design's website shows 43 gallons. https://www.granddesignrv.com/showro...ns/22mle#specs

The fresh water tank itself has a capacity of 37 gallons (according to information I can access as a moderator). The difference (6 gallons) historically was because of the water heater capacity. With today's tankless (if that's what your Imagine has) then there's no extra 6 gallons. If there's a traditional water heater, then you will have the extra 6 gallons, or 43 total.

That your Imagine holds 31 gallons instead of 37 gallons (I assume you had a meter of some sort) is not terribly unusual. Due to the vent and overflow there is some "head room" in the tank that won't get filled.

BTW--welcome to the forum, David.

Howard

[Country Campers]

I understand that we lose a few gallons bc of the overflow, but this is ridiculous... I own an Imagine XLS 22MLE and discovered today that the 47 gallon fresh water tank will only hold 31 gallons. 16 gallons short of the stated capacity?? If any other members have the same model I am interested to know if this is normal for the 47 gallon tank.

If you are filling the tank until it water comes out of the overflow tube then it will cause a syphoning effect that will drain your tank to some kind of level until it quits. The manuals state to fill until the tank sensors say it is full and then stop filling, this will leave about a 1" air gap at the top of the tank and should not introduce the syphoning effect. Some owners have installed a shut off valve on the overflow tube to be able to fill the tank full and not lose any water to the syphoning effect, do this at your own risk as there is plenty risk involved.

Brian

[DavidBarnes792]

I understand that we lose a few gallons bc of the overflow, but this is ridiculous... I own an Imagine XLS 22MLE and discovered today that the 47 gallon fresh water tank will only hold 31 gallons. 16 gallons short of the stated capacity?? If any other members have the same model I am interested to know if this is normal for the 47 gallon tank.

[PineconeNW]

If the water tank is 36" x 60" and the vent port is 1" below the top, you would lose about 9 gallons. 54 - 9 = 45.

I just read through the thread again and I think I missed this post.
The vent is on the side and your math explains the issue.
Thank you.

[Mwestall]

It’s a shame but I understand that all the fresh water capacities are calculated on the tank measurements and not on the actual amounts they will hold. The overflow drain causes an area in the top of the tank that will not stay filled and several gallons will always drain out. I boondock a lot and bring extra water in bladders placed it the bed of the truck. Luckily you now know the issue and you can plan around the actual capacity. It would have been nice if the company brochures actually were correct.

[PineconeNW]

Fantastic!
And look at those straps and the angle supports. It should drain well. Maybe I will put my Beech Lane Camper Leveler under the other side next time.
Great picture.
Thank you!

[TucsonJim]

Both drawings above indicate a lowered ramp feature for the drain.
Wish I could find a picture of the undercarriage of a 297rsts.
Some day when I am retired and bored I am going to drop that coroplast and have a look around.

Here's a photo of the water tank on my 2017 297.

[PineconeNW]

Both drawings above indicate a lowered ramp feature for the drain.
Wish I could find a picture of the undercarriage of a 297rsts.
Some day when I am retired and bored I am going to drop that coroplast and have a look around.

[Cate&Rob]

TedS
I was just doing the same calculation . . . but, you beat me to it.

To the OP . . . not really a “defect in the design” . . . but a valid comment that Grand Design should allow for the 1” air space at the top of the tank when specifying usable volume.

Rob

[TedS]

If the water tank is 36" x 60" and the vent port is 1" below the top, you would lose about 9 gallons. 54 - 9 = 45.

[PineconeNW]

Another email came from GD Friday. I now have two GD people
confirming the trailer is built with a 54 gallon tank. Is it
worth dropping the coroplast to confirm?

Since others in this thread say they too have the 54 and it will only
take 45 I will assume it is a defect in the design. Perhaps
belly sag on the tank?

[Country Campers]

My paper says the same thing but I have only been able to get 47 gallons in the fresh tank. The over flow tube on the fresh tank is set about 1" or so below the top of the tank. The full level indicator is located at about the bottom of the over flow tube outlet. Grand Design recommends that the fresh tank be only filled until the full indicator lights on the control panel. The tank may be built to the 54 gallon capacity but whether it holds that much is another story. I have always filled my tank until it just starts to trickle out of the over flow tube and the inline water meter usually reads around 47 gallons, depends on the slope of the RV while filling, I have not tried to fill while leveled on a site.

Brian

[PineconeNW]

Went to the trailer this morning, found this in the papers that came with it.
"Fresh Water (w/o HWH): 54"

[PineconeNW]

The lowered wedge on the end should allow the tank to empty completely.