quick isolator/doubles question

[booth22]

Setting up some doubles, I have the isolator open and a reg on each tank. If I only have one tank open (along with the isolator) I was under the assumption the one open tank would provide air to either reg. However, with the isolator open, as soon as I shut down one post, I lose pressure on that reg/spg.

When I had the tanks filled, the isolator was open and both tanks were filled off one post, so at least the isolator worked at that point, but no luck now? Am I confused here or just not doing something right? I'll be taking them into the shop on Monday, but thought some SBers might help in the meantime....

 

[Ben_ca]

It's the other way.... The valve controls the post(reg).... The valves just stop the gas from entering that particular reg.

Here's a visual

http://www.cavediving.com/how/manifold/index.htm

Does that help?

 

[booth22]

awesome thanks!

 

[Dive-aholic]

As long as the isolator valve is open, regardless of what position the post valves are in, air will mix between the two tanks. Shutting down a post is only done if you have a 1st stage failure. Any other type of failure requires the isolator to be shut down otherwise you'll lose all your air from both tanks.