Can anyone tell me what this is

[alain h]

It’s under the sink cabinet in the bathroom on my Vibe

[fonzie]

It is a vacuum break valve for your black tank flush ....

[alain h]

Is there a maximum water pressure that will open the valve
I can’t get nothing in with our campsite water
I’m not using a restrictor
The plumbing all looks good
But no water going in ????

[fonzie]

Follow the lines and make sure it is plumbed properly as picture shows. There has been many of these that were plumbed in reverse and water will not flow.

[alain h]

Already mention that the plumbing is all good

[alain h]

We check all the lines

[Flybob]

Check that the back flow prevention valve is not installed backward. It has happened.

[SailorSam20500]

Are you saying the black tank flush doesn't work, or that you aren't getting water flowing via the city water connection?

[Scrapper]

What others have said, take a better look at the picture fonzie posted. The check valve/vacuum breaker is directional, meaning the water can only go one direction through it.

[Mr Towed]

Originally Posted by alain h

Already mention that the plumbing is all good

I think if that was the case you wouldn't be asking this question.

[alain h]

Originally Posted by SailorSam20500

Are you saying the black tank flush doesn't work, or that you aren't getting water flowing via the city water connection?

Yep you got it

[alain h]

Originally Posted by Mr Towed

I think if that was the case you wouldn't be asking this question.

Thanks

[alain h]

My original question was
Is their a maximum water needed to open the valve
The plumbing is all good

[alain h]

Opps pressure that is

[dbledan]

Originally Posted by alain h

Opps pressure that is

Mine has worked as low as 35psi because I had my compressor set that low on accident once. I never tested how low they go.

Typically if they don't pass water they are backwards or broken.

They tend to fail between being plastic, and freezing the first winter they don't last long. Lots of folks don't winterize them because they are not hooked to city plumbing. Sometimes you get lucky because they are not pressurized but I still blow mine out. Had a larger metal version one on old sticks and bricks for sprinkler and had to rebuild it every 3-4yrs even when I blew that out every year.

Since you are sure plumbing is right then would be a well spent $40ish to get a replacement.

[Krazo]

if you look closely on the valve it has an arrow for the direction of flow. Mine was installed backwards and I had to flip it to get my black tank flush to work properly. what I would do is hook water up to the black tank inlet, open water valve and you will notice (if valve is installed backward) that the water hose will quickly build up pressure. Go to the location of the valve in your picture and squeeze on both sides of the valve. One will have pressure and the outher side will not. You should be able to tell if it’s installed wrong. If it’s wrong, Mark the lines, use a pair of snips to cut the clamps off, and switch the hoses around. Make sure that the valve stays zip tied up and above the water level of the toilet.
I have a post on this with pictures. I believe the thread is “black tank flush not working”

[alain h]

The lines are installed properly

[Krazo]

Forgot to mention, this valve is actually two things. It is a one way check valve and a anti syphion valve/ vacuum break.

[Krazo]

If you get pressure on one side then the check valv is bad and you will need a new on. If the anti syphion part was bad it would be spraying under the cabinet.

[Krazo]

I have used my black tank flush a a camp site that had a premanent 15# reg and worked fine just didn’t sound like it was spraying very hard.