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.

[boondockdad]

Robert,

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

http://www.airforums.com/forums/show...ferrerid=16139

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?

[HowieE]

No, in fact it wants to be open for winterizing to make sure antifreeze gets back to the city connection. If you do not blow out the system from the city connection side water would be trapped in the pipe and most likely freeze.

As far as switching back and forth during the year depending on how you are hooked up there is no reason to do that, just leave the valve closed.

Thinking about it I can't come up with a reason for the valve at all. It doesn't isolate anything for service except the city connection. Then again I can't come up with a reason for the check valve as all city connection have always had a check valve in it. Looks like a solution to a problem that doesn't exist.

[ROBERT CROSS]

Originally Posted by HowieE

Looks like a solution to a problem that doesn't exist.

I'm smiling on that one Howie......now if we could only get some solutions that do.....

[2airishuman]

Originally Posted by ROBERT CROSS

...Winter shut down is approaching and I still don't know the purpose of the unit. The brass fitting is a one way valve...

hi rc

it goes something like this...

there is an external faucet on the classics, which can use water from the tank or shore connection.

to 'winterize this faucet a shutOFF handle ( below the brass section in your pic ) is turned to CLOSE,

then the outside faucet opened to drain the remaining 3 feet of water in the line.

(( i leave THAT external faucet OPEN during the winter once the shutoff valve is turned)) EXCEPT when connected to shore water.

should a camper wish to USE the freshwater SHORE connector after winterizing the external faucet/fresh tank connection...

THAT brass section lets it happen, connecting the shore water source to the main internal plumbing.

ken (w7ts) posted a thread last month on this and got the 411 from the mothership here, see post #12...

http://www.airforums.com/forums/f443...lve-55224.html

typically winter camping is simplest just FILLING the tank and NOT leaving ANY outside hoses connected,

but THAT brass gizmo lets folks use a shore hose for water... after winterizing the outside faucet

IF one does use shore water, the outside faucet needs to be OFF while connected,

but after UNhooking the shore hose, just open the outside faucet again and 3 feet of water will drain out.

cheers
2air'