The dreaded gurgle
I had a sort of similar experience this weekend. First time using the fresh water tank. Our one previous trip we used water hookup.
Tank full, pump on....no water, heater would not fill. Bypass valves all correct. Long story short, I noticed a valve on the backside of the line going to the electric pump (after 10 minutes of head scratching) Hard to see the darn thing. Turned it on and all was well.
My old trailer did not require this and I assume I should turn it back when I next go to a water site.
Harv & Deb
2015 Flagstaff 27RLWS
2010 Ram 2500 4x4 crew 5.7 Hemi, 3.73
Equalizer 1200 4 pt. Tekonsha controller