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Discussion of diving methods and equipment available prior to the development of BCDs beyond the horse collar. This forum is dedicated to the pre-1970 diving.
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EHowe
Master Diver
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Joined: Sun Aug 28, 2011 2:59 pm
First Name: Edward
Location: Chicago

DW Mistral free flow at low tank pressures

Sun Aug 17, 2014 8:17 pm

Took my trusty Mistral for a dive yesterday to test my rebuilt J valve. I started with approx. 1700 psi. I noticed as pressure dropped, even before the J valve closed, a constant air flow that could only be stopped when going into a head down position. I'm not talking about a huge free flow, just a steady air flow strong enough to bypass mouth piece valve and DBE. It does not seem to happen at higher pressures. Maybe spring getting weak? I did replace seat and spring when I rebuilt reg a couple of years ago and it has a handful of dives since.

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Ron
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Re: DW Mistral free flow at low tank pressures

Sun Aug 17, 2014 10:10 pm

There are a few things that can cause this:

-weak HP seat spring
-Seat has been sanded too many times (deprecated due to Bryan making seats)
-Using a new, thin first stage filter without a washer (I've done this)
-Levers set too high


Work your way through those and keep us posted on what you find :) The two most common, in my opinion, are the lever height and using a thin filter with no washer.
The impossible missions are the only ones which succeed. -JYC

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