City Fill not working (I think)

[jdux999]

Hello All. I have a 2018 Redhawk and I filled my tank yesterday but I'm down to 1/3 full now and I haven't used much water. Is there something I'm doing wrong when filling? Does that little filter have to be in a certain position (cone facing in - cone facing out)? I have a water monitor that counts the gallons going in that I will use next time I fill up, but if I'm doing something wrong, I'd rather know before I fill up. Is the only way to tell if the tanks are full is when the overflow tubes start to flush? Thanks again.

[WinnieView]

Did you drive the Redhawk in between fill ups?

[jdux999]

I have driven between full ups. I don't see any obvious leaks and my water pump isn't coming on every few minutes so I don't think I'm losing water internally. I will use the gauge next time to see if water is actually going in.

[Berjr]

Originally Posted by jdux999

I have driven between full ups. I don't see any obvious leaks and my water pump isn't coming on every few minutes so I don't think I'm losing water internally. I will use the gauge next time to see if water is actually going in.

Most likely the vent lines are siphoning out the tank

[Camper_bob]

Originally Posted by Berjr

Most likely the vent lines are siphoning out the tank

Yup. A known issue with virtually all RVs

Lots of people put ball valves on the vent lines. Just need to make sure you open them if you're using the pump, or filling the tank.

Somewhere on here a user posted a dealer bulletin detailing Jayco's fix. It involves replacing one of the vent fittings on top of the tank with a 45 degree fitting instead of a 90 degree fitting in an effort to break the vacuum by sending one vent hose upward.

Another user created a manifold out of PVC that does the same thing but better.

Bottom line is that when you're moving, you're losing water out the vent lines, and sometimes you can lose A LOT.