Question about SCBA valves

Forums Air Tanks, Pumps, & Compressors Question about SCBA valves

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    LTU-013
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    Does anyone use SCBA tank with MSA valve:

    Do you have to press knob to open?

    I have Scott valve:

    In order to open valve you have to press in that black knob, it has stoppers you can't just turn to open

    I guess it's a good safety feature if you are a firefighter, but I'm not running with this tank to a burning house.

    If you are trying to hold your rifle with one hand to see gauge and operate 4000+ psi tank with another – it's bit annoying, when you have to press that knob, tank slides, hose kinks, rifle falls…

     

     

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    Jonah
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    You can remove the spring.  Search the forum, its been discussed before.  Don't have the link.

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    Eaglebeak
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    If you have the valve, of the bottle, like in the photo. It's a good idea to remove that snorkel from the bottom. It prevents purging of any unwanted moisture. It's only there to prevent moisture from being inhaled when the bottle is mounted valve side down on the SCBA backpack.

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    Tominco
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    Remove the locking nut from the center of the black knob. Pull it off. Remove the spring. Re-install. That's all there is to it. 👍

    You can do this with the bottle full or empty, it makes no difference.

    The MSA's I've seen did not have the "push to open" feature like the Scott's.

    Happy Shooting,

    Tom

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    LTU-013
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    Thanks a lot, I didn't know it's possible, will do that tonight.

    Eaglebeak, for that I guess I'll have to wait for end of the season to completely empty tank

    Do you just pull that with pliers or cut?

    Thanks

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    sagen
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    My MSA doesn't have the "push to close" feature that we dont want. 

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    spysir
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    I have the Scott valve, on mine I did not need to take anything apart to defeat this feature I was able to simply turn the nut in – recall less than 1 full turn?-  and it now works just like a scuba valve. Perhaps there is a reason I shouldn't have? And or maybe they are not all the same? Haven't had any issue in over a year.

     

    John

    • This reply was modified 1 week ago by spysir.
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    Eaglebeak
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    You should be able to remove it with pliers. It's not a big deal and you shouldn't have any moisture unless you get a bad fill. I thought that while you had the valve out, you might as well remove it. It can definitely wait until you need to remove the valve for a more important issue.

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    duster_360
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    I just received a 2012 Interspiro 45 min SCBA tank with the Scott valve and the on/off does not "push to open". The spring is still there, so it must have defeated it in some other way – turn the nut as mentioned above? 

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    LTU-013
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    Thanks a lot. It took just 5 minutes and it really works, now I can open and close tank with one hand, don't have to push.

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    porkey
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    Fill adapter/Scott valve leaks??? somebody please help……I have a SCBA Scott tank and Scott valve 4500 psi, the problem is my fill adapter will hold about 2000psi when I fill my PCP rifle and then starts to LEAK from around the threads of the valve …….You can see a picture of this valve posted Aug. 9, 2018 …….What I don’t understand is if you look closely at the threads for the fill adapter there is a small hole drilled into the thread, this is what appears to be leaking……. I purchased a new fill adapter from pyramid air and I have the exact same problem …….What is this hole for…..how do I stop the leak???

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    Centercut
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    The pressure boundary is between the nipple the goes inside the threaded portion of the valve assembly and the seat inside the threads. The threaded portion and hole are not part of the pressure boundary. 

    Ensure both your fittings are CGA 347. If one is CGA 346 the nipple could be shorter and not be long enough to seal the pressure boundary. The Scott valve in the upper photo is the correct fitting. Perhaps a photo of what you are trying to join would help.  

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    porkey
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    Hi Centercut and everyone on the forum……I think you solved my problem……..I think I have a cga347 fill adapter on a cga 346 valve. Do you know for sure if the Scott valve in the lower picture is a cga346 or cga347….I can also check with the dive shop who fills my tank…….Thanks for the help you have me on the right track to solve my problem……Porkey

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    Centercut
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    The Scott valve above is CGA 347. What does your fill rig look like?

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    porkey
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    Hi Centercut and everyone on the forum……..here is the picture cga347 fill adapter and tank valve……I was thinking maybe I should try a new fill adapter that you tighten with a wrench and one that does NOT use a rubber o-ring……..I have seen pictures of that type on e-bay??? 

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    Centercut
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    So the gage on the tank valve goes up past 40 and then a yellow line that says “full” correct. 

    On the fill nipple, I’ve never seen them with a rubber oring. The hand tight ones usually have a delrin (hard plastic) type gasket. Orings must be “captured” in some way as in a groove or by the use of a dowty seal. They’re usually white or orange. 

    When you insert the nipple can you feel it seat inside before you tighten the knurled knob? 

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    Eaglebeak
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    Are you certain that it is leaking from the bottle to adaptor joint? If your Oring is good and the mating surface isn't damaged, it can't leak from there. Check where the shaft enters the gauge block. There is an Oring in there that can leak if it has been under or over tightened. Also on that type of adaptor, the bleed valve needs to be nipped up quite firmly or it may leak at higher pressures as well.

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    porkey
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    Hi Centercut and Eaglebeak, It looks like the black rubber o-ring seats in the valve with a very slight taper……I just don’t like this hand tight design I even tried to tighten it with a large pair of pliers and it still leaks…….Maybe this valve is not designed for o-ring???  I hope the guy in the dive shop who filled the tank has some idea…….the only problem is he only open part time……no regular hours!! If I cannot catch him in the shop soon I am just going to order the type with a solid nipple and tighten with a wrench…..Thanks to both of you for your help and sharing your knowledge with me and everyone on this great forum……I will post a update when I figure this thing out…..Thanks again…..Porkey

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    jking
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    Looks like the gauge on your tank only hoes to 3000 or so, couldn’t really see it that well. If it’s a CGA 347 it ought to be able to go as high as 4500. You might have a lower pressure tank. 

    Jimmy

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    jking
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    Refer to the valve at the top of the thread for comparison. Just a thought..

    jk

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