Dry Camping Setting back flow

[Bauernfeind]

I use my 5th wheel during the winter months in my backyard for overflow guests and I fill the fresh water tank so I don't have to worry about hose freezing for those not acquainted with any RV life. Anyway, when I filled it this time and set it to dry-camping, turned the pump on, water flowed out of the city water connection. Any ideas why?

[RoadrunnerII]

There's a screen inside that connection did you possibly turn it around? Behind it is a check valve
If screen is cone shaped and in backwards it can hold the check valve open. Otherwise you could have debris in the check valve

RoadrunnerII

[Bauernfeind]

As soon as I read your reply to my post the light went on and somewhere in the recesses of this old brain I remember this happening to me once before -- on another RV but the same problem. Sure enough, I checked and the screen was installed upside down pushing the valve to the constant open position. Thanks so much!