mystery plumbing fixture?

[Tree]

Hi. I've discovered the attached brass thing under the sink in our 28 C/B Argosy. Any ideas what function it serves and if it is necessary (it currently leaks under the round part at the top.

[Trnpk Crsr]

It's vaccum breaker/back flow preventer. What is it attached to?

John

[A W Warn]

It is a pressure relief valve.
If water pressure exceeds a set pressure point it discharges water through the flexible hose.
Excess water pressure can occur either from the water supply or from a malfunctioning water heater. There must be a pressure relief valve somewhere in the fresh water system. In both of my trailers the pressure relief is on the water heater.

This is similar
http://www.wholesalepumpsdirect.com/...ief-valve.html

[HowieE]

I vote for back flow preventer.

It would be interesting to know what it is hooked up to. They are normally at the city supply connection not within the trailer serving one function.

[A W Warn]

Some examples:

http://www.airforums.com/forums/f227...uet-69335.html

http://www.airforums.com/forums/f163...ter-94760.html

http://www.airforums.com/forums/f44/...ak-153941.html

If you can get a photo of the top of the device, there should be information there.

[Shacksman]

Originally Posted by Tree

Hi. I've discovered the attached brass thing under the sink in our 28 C/B Argosy. Any ideas what function it serves and if it is necessary (it currently leaks under the round part at the top.

It's a vacuum break usually attached to the toilet to keep water from feeding back into the system.

[A W Warn]

Originally Posted by Shacksman

It's a vacuum break usually attached to the toilet to keep water from feeding back into the system.

It sure looks like this one!
Maybe I'll have to admit I'm wrong :-0

http://www.shopbackflow.com/watts/wa...vb/watts-288a/

[Tree]

It is high up under the counter top so without disassembly we can't see the top. The plastic line attached to it goes to a spray handle (for use in the toilet?). The plumbing system ends in the bathroom - so vacuum break makes some sense. But then so does a pressure reducer if the spray is in the toilet. I have to do some plumbing on the trailer next week so we may be able to solve the mystery.

[Zil]

It is incorrectly called a back-flow preventer. It is a anti-siphon valve, or what is called a vacuum breaker. It prevents a low pressure event from drawing water back into the system. It will not stop higher pressure from feeding back.