Water overflow before tank is full

[sanstead]

My Jayco Eagle Ht starts to spill water out of the overflow tube before the tank is full.
Water capacity is 42 gallons. 6 is hot water. Doing the math I should be able to put in 36 gallons. I would estimate on the low side 32 gallons at least. My water meter says 28 and the overflow starts. It drains out approximately 6 gallons.
My water gauge inside the trailer says the tank never gets fuller than 1/3 so that is obviously not working right.
Any thoughts?
Maybe at 28 gallons it is full. I have only drained the tank with the little white valve not the whole system using the low point valves.

[Joan617]

Hot water is not normally listed as part of your freshwater capacity so you should have 42 gals to play with.

We've seen it before on this forum where Jayco has installed tanks smaller than listed in the brochure ("specifications subject to change...")

You are correct that most users do not regard the OEM fluid level meters as accurate. Somehow even freshwater tanks with no flotsam get spoofed.

Was your rig level at the time? A lot have rigs have trouble with siphoning from the overflow vent, but it has to reach that level for siphon to start.

Hard to say.

[sanstead]

Thanks!! We will be upset if the tank is smaller than specified!