Fresh Water Tank Vent`

[Randall42]

I have a 12 390BH. The fresh water tank acts like it has no air vent or its closed or blocked.
Tank pilows up when filling and colapses when its draining. I see three lines near the top of the tank One is fill, the other 2 go someplace unknown.
All 3 have crimp end fitting so cant just unscrew those. The tank is near emplty and collapsing. I removed the fitting going to the pump and it vented there and the tank went back into close to normal shape.
Can someone tell me where the vent line is and if there is an on and off valve there?
THX in advance
Randy
Salt Lake City

[Eric B FR Diesel]

Originally Posted by Randall42

I have a 12 390BH. The fresh water tank acts like it has no air vent or its closed or blocked.
Tank pilows up when filling and colapses when its draining. I see three lines near the top of the tank One is fill, the other 2 go someplace unknown.
All 3 have crimp end fitting so cant just unscrew those. The tank is near emplty and collapsing. I removed the fitting going to the pump and it vented there and the tank went back into close to normal shape.
Can someone tell me where the vent line is and if there is an on and off valve there?
THX in advance
Randy
Salt Lake City

Hey Randy,

the fresh water tank is usually vented using the over flow valves... check to make sure they are not blocked, should be two of them coming off the fresh water tank.

[edgewant]

I have the same problem. I have located one overflow hose and have verified it’s not blocked. Tank billows up and touches bottom of black and gray tanks. I’ve never been able to get water to come out of the overflow line.

I just have to open the pump access door and monitor when filling or sanitizing.