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Fresh water issue.

MaxMax Member Posts: 6
in Heating/Plumbing & Winterizing
I have a new 400. When I fill the fresh water tank, the overflow runs and empties the tank to 3/4 full rather than allowing me to fill the tank, completely. Any idea what might be the issue? Thank you. 
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Comments

  • Sharon_is_SAMSharon_is_SAM Administrator Posts: 9,739
    How do you know that the tank is only 3/4 full - the tank monitor?  They can be inaccurate.  You can fill the tank, then measure the output to have something objective.  
    Sharon / 2017 T@B CSS / 2015 Toyota Sienna Minivan / Westlake, Ohio
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  • manyman297manyman297 Member Posts: 1,357
    If your camper isn't level you can get false readings. The sensors are on the left side of the tank. So if your camper is leaning to the right then one side of the tank is more full than the other. BUT since you have water coming from your overflow you might have an issue with the sensor. Or they installed them too high in the tank.
    2021 400 BD
    2020 Tacoma TRD Off-Road 
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  • BridgerSunsetBridgerSunset Member Posts: 101
    A few years ago while we had our 5th wheel, we followed the Jayco forum.  There were numerous complaints of this same nature - and I believe it stemmed from having a siphon effect from the overflow.  There was significant water loss in some cases.

    You might try a search over there.  I don't  remember the fix, but there was a solution put forth.
    2021 T@B 400 Boondock  - Chev Silverado 3500HD 6.6L - Toyota 4Runner 4.0L
    SW Montana USA


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  • stp2136stp2136 Member Posts: 16
    We have a 2022 T@B 320s and the nominal fresh water capacity is 19 gal. but I suspected it held less.  So I measured the quantity when filling and the tank started overflowing at 17 gal.  I am guessing the 19 gal nominal capacity comes from measuring the outside tank dimensions (I have seen that on previous trailers) and the sides of the tank may be a bit concave.  Also the overflow may be high on the side of the tank rather than on top.  Can't prove either of these things as I haven't pulled down the cover to look.
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  • MaxMax Member Posts: 6
    Well, it’s certainly not critical, but certainly irritating. Thank you all for your input. 
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  • Denny16Denny16 Member Posts: 5,431
    The water tanks hold more water, than you are able to pump out or drain out, due to the location of the hoses.  So a 1.5-2 gal difference is normal.  OP didn’t mention which year his TaB is, but most overflow vents are in the top of the tank, so no siphon effect is possible from the overflow vent.
     Cheers 

    2018 TaB400 Custom Boondock,  Jeep Gladiator truck, Northern California Coast.
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  • MaxMax Member Posts: 6
    Our TAB is a 2022, just took delivery. Thanks for your information. Max
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