What's this for?????

[ROBERT CROSS]

Found this manifold and shut-off valve assembly leaking during Spring get ready this season. The leak has been repaired but Winter shut down is approaching and I still don't know the purpose of the unit. The brass fitting is a one way valve. It's located under the bathroom sink between the cabinet and skin. I found it in the plumbing schematic but no mention of it's function.

HELP

[HowieE]

Boy you got me on that one.

Can you give us an idea of where the pipe goes on either side?

Never seen a check valve that did not have a hinged clapper in it.

[biggoofball]

I've seen check valves like that before, but never as a bypass of a shut off valve.

I cannot come up with a reason to do it, however.

[finalcutjoe]

Robert,

this looks suspicously like my city water shut-off and inline backflow preventer... check out this thread:

City water inlet shut-off valve?

basically, keep it closed, except when winterizing

-J

[ROBERT CROSS]

The line runs from the city water connection to the crapper.

Thanks for the link Joe, the shut-off valve has been in the pictured position, (open), since we got the trailer. We have never been hooked to city water, dockers at heart, nor have I done anything with it for winterizing.

SO WHAT DOES IT DO???

[HowieE]

The way it is drawn on the Airstream diagram it is a backflow preventer and the hand valve should be CLOSED to keep your pump from backflowing to the city if the city pressure drops.

[ROBERT CROSS]

Thanks Howie,

We have never been "hooked-up" so that wouldn't be a problem.

But what a PITA to get to for those who go both ways.

It's always been open, any reason to change for Winterizing?