Hissing sound when valve is open (I changed the o-ring already)

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Kairoos

Contributor
Messages
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Location
West Palm Beach, Florida
# of dives
100 - 199
I changed the 014 o-ring that goes between the first stage and the valve and it's still hissing. I also tried a different 1st stage and it still hisses. The valve is a Sherwood valve, and is one of the convertible ones with the insert for yoke cylinders.

The one thing I did recently is leave the reg set pressurized for a while, but I figured if anything that would be a negative to the 1st stage, not the valve, and I checked the IP on the 1st stage and it's around 150psi, which seems a bit over spec, but that's something else.

I'd assume this part here is the issue:
s9G2wPI.png

I don't know the names, and the diagrams I've looked at don't have names. Ideas?
 
#17 o-ring is bad. Don't have to depressurize tank. Take the knob off, pull the stem out, change/lube the o-ring, reassemble. try again. If #12 was the problem, which should be the burst disc assembly, it would have bled off. Only way for it to leak when open but not closed is that #17 o-ring which seals the chamber when it is opened

tn
 
#17 o-ring is bad. Don't have to depressurize tank. Take the knob off, pull the stem out, change/lube the o-ring, reassemble. try again.

tn

Do you happen to know what size that o-ring is? 010?
 
If it is hissing from between the regulator and the valve then it is quite possibly the O-ring on the back (inside) of the convertible plug (25) If it is coming from the handle - then it is probably the o-ring described above.
 
If it is hissing from between the regulator and the valve then it is quite possibly the O-ring on the back (inside) of the convertible plug (25) If it is coming from the handle - then it is probably the o-ring described above.
It does sound like it's coming from that side. I'm going to have to find a hex key big enough to remove it and check that too.
 
Bathtub. Put a towel in the bottom of the tub to protect it, first. Then lay the tank on it. Fill with water and be sure.

Plan to rebuild the valve next inspection.
 
it all depends on your valve unfortunately. You can take the o-ring out and take it to your LDS and they should be able to swap it for you. You will need a screwdriver with a notch cut out of the center to get the knob off though. If you are going down to Fort Lauderdale, Add Helium will likely do it for free for you. It takes 3 minutes to swap out. That said, the valve probably needs a proper rebuild. While that o-ring is the first to go, it is usually the valve telling you that it's time to give it some TLC. Should be done every hydro cycle but is often overlooked
 
I'd lay odds on the insert oring. Easy to replace and worth a try before you start taking the value apart.
 
sorry, what they said. didn't realize you had a convertible valve. Check the DIN side O-ring first. Should be a 111 or 112, not sure. Again LDS will have them if yo udon't
 
it all depends on your valve unfortunately. You can take the o-ring out and take it to your LDS and they should be able to swap it for you. You will need a screwdriver with a notch cut out of the center to get the knob off though. If you are going down to Fort Lauderdale, Add Helium will likely do it for free for you. It takes 3 minutes to swap out. That said, the valve probably needs a proper rebuild. While that o-ring is the first to go, it is usually the valve telling you that it's time to give it some TLC. Should be done every hydro cycle but is often overlooked
The valve is actually new. The tank is less than a year old! I will definitely check the DIN side.



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