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  1. #11
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    Jun 2011
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    St Petersburg, FL
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    Quote Originally Posted by Dsix36 View Post
    I have found that running a needle valve on a eccr unit is absolutely the best of both worlds and is by far my personal preference. It will leave the unit stock with the exception of swapping the O2 MAV for one with a needle valve built into it. Chris Kenneday down u der is the go to man for these. He will build exactly what you want at a good price.

    You can run it manually with a low setpoint for a parachute but not have any depth limit caused by a cmf type unit.

    For the rEvo guys who might argue, there is no messing around with having to convert to eccr for deep deep dives or have rich dil plumbed in for it.

    It was the first mod I did in my Defender and I still think it was awesome. Tuning the flow between scooter dives and fighting flow turned out to be just a small twist of the needle and the placement never bumped it to change adjustment.

    Needle valve is a no brainer for me and I am amazed that more people, and even manufacturers, do not utilize them.

    Sent from my LG-M150 using Tapatalk

    Pardon my ignorance but how does a needle valve work on an eCCR. I thought flow was controlled by the solenoid. How does the needle valve effect flow through the solenoid?


  2. #12

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    Quote Originally Posted by rddvet View Post
    Pardon my ignorance but how does a needle valve work on an eCCR. I thought flow was controlled by the solenoid. How does the needle valve effect flow through the solenoid?
    It does not control flow through the solenoid. By replaceing the stock MAV with one that has a needle valve built into it. The needle valve lets the O2 bypass the button and flow into the loop. The button still works for addition. Setting the setpoint low and running manually works like cmf but adjustable. Thus no depth limit either.

    Sent from my LG-M150 using Tapatalk

    No naked pictures, just dive stuff. Click Here

  3. #13
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    Jun 2011
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    St Petersburg, FL
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    Quote Originally Posted by Dsix36 View Post
    It does not control flow through the solenoid. By replaceing the stock MAV with one that has a needle valve built into it. The needle valve lets the O2 bypass the button and flow into the loop. The button still works for addition. Setting the setpoint low and running manually works like cmf but adjustable. Thus no depth limit either.

    Sent from my LG-M150 using Tapatalk



    Figured it was something simple I was overthinking. Thanks for the lesson.


  4. #14
    Member
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    Sep 2009
    Location
    Gainesville, FL
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    186

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    Quote Originally Posted by Dsix36 View Post
    Why bother blocking the first stage? If you just leave it compensating then you will not have any depth limit and not have worry about adjusting the IP.
    Because blocking the first stage eliminates the need to adjust the needle valve with depth changes. Once the needle valve is dialed in to the diver's metabolic needs, it only needs to be adjusted when those needs change, such as swimming versus scootering. In the several years that I've been diving a needle valve I haven't had the need to go below 400 ffw so haven't touched the IP.

    J. Charles Roberson
    FATHOM Dive Systems, LLC
    jcr@fathomdive.com

  5. #15

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    Does any of the needle valves close completely shut? I have a buddy on a Pelagian, and his needle valve always has some flow through it even when closed to minimum. I'm asking because I would not like to have to close the O2 valve on the cylinder while on the boat or land before and after the dive to avoid having it fill the loop constantly and also wasting O2, especially if you leave it open for a long time. I know this practice is the standard for any mCCR or hybrid. I do close the cylinder valves when I'm not wearing the unit, but whenever it is strapped on to me everything is on and operational so having to close the O2 if wearing the unit on a longer boat ride or something similar is not something I would appreciate if I ever was to try a needle valve.


  6. #16
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    Apr 2015
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    Arizona or traveling
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    I don’t know of any needle valve that closes to zero. If it did, it would damage the orifice. My pre-jump checklist includes checking all valves, so I’ve never had an issue with it.


  7. #17

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    I played with a couple. Charlie designed the Fathom CCR around his with a fixed IP. It is the nicest I've seen and with the needle between the inlet and outlet it does not get bumped, and half turns can be measured and dialed in.


  8. #18
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    Sep 2009
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    Gainesville, FL
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    Quote Originally Posted by Raptor^ View Post
    Does any of the needle valves close completely shut? I have a buddy on a Pelagian, and his needle valve always has some flow through it even when closed to minimum. I'm asking because I would not like to have to close the O2 valve on the cylinder while on the boat or land before and after the dive to avoid having it fill the loop constantly and also wasting O2, especially if you leave it open for a long time. I know this practice is the standard for any mCCR or hybrid. I do close the cylinder valves when I'm not wearing the unit, but whenever it is strapped on to me everything is on and operational so having to close the O2 if wearing the unit on a longer boat ride or something similar is not something I would appreciate if I ever was to try a needle valve.
    Most needle valves are not designed for shut-off service since they are fragile and this could potentially damage the needle. I use the handle stop to set the minimum flow to < 0.1 lpm, which will eventually fill the counterlungs. If I end up waiting on the surface geared up for any length of time, I just open the bov momentarily to vent the loop as needed. No big deal and wastes very little oxygen.

    J. Charles Roberson
    FATHOM Dive Systems, LLC
    jcr@fathomdive.com


 

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