DIN fitting Air Leak

[Abcdavidson]

Hi all.

This problem has me stumped so any advice would be greatly received!

I've been using Scubapro Mk25 and Faber 12ltr for the last 8 months and never had any problems. A couple of weeks ago I decided to buy a 15 as an extra. Now, every time I connect my 1st stage I get a massive leak at the connection.

What have I done so far? I have tested my regs (although I was pretty sure anyway) on other cylinders to see if they were at fault. I have tested a few sets of club regs on my new cylinder and they are fine too! it just seems to be a compatibility issue with this one cylinder and one set of regs!

I have cleaned the 1st stage threads and inspected the cylinder threads, again both are fine. Then I changed the 1st stage 'o' ring, this is were the fun starts. After cleaning and setting the new 'o'ring I put it all together and ' 'voila' it looks like I'm good to go. I dismantle it and do it again to be sure, the leak has returned! I gave it another go, this time slightly wetting the 'o' ring and the leak is still there...

My regs continue to work fine on my 12 & my 15ltr is currently a very expensive door stop! :eek:


any ideas?

Thanks in advance

Adam

[Edward]

Hi,

Are you using the same pressure rated DIN fittings.

There is one for 232 bar and another for 300 Bar.

The 300 DV will fit a 232 cylinder, but for safety reasons a 232 DV will not fit a 300 cylinder (Its too short and leaks).

Just a though.

Regards

Edward

[Abcdavidson]

Hi Edward,

The 15 is a 232 the same as my 12

but thanks for the reply! I reckon this is just a real odd case!

Adam

[Gordon]

Its not something daft like a 300 bar valve in a 232 bar cylinder?

G

[Abcdavidson]

Its not something daft like a 300 bar valve in a 232 bar cylinder?

G

Thanks for the reply Gordon but, no. All 232 kit

Adam

[Twinsetmad]

I've come across this too..... but for me its been an intermittant fault... sometimes just taking it off and putting it back on solved the leaks... in the end I put an MDE valve on the cylinder and its been ok since. The one I replaced was an SOS valve...

My advice would be to get the shop to change to valve.... or if you have a spare swap it out yourself.

[Abcdavidson]

I've come across this too..... but for me its been an intermittant fault... sometimes just taking it off and putting it back on solved the leaks... in the end I put an MDE valve on the cylinder and its been ok since. The one I replaced was an SOS valve...

My advice would be to get the shop to change to valve.... or if you have a spare swap it out yourself.

Thanks for your help, it appears that mine is intermittent too. I just wouldn't trust it until is was 100% all the time. Looks like it's off to the shop for me!

Adam

[Ian@1904]

Looking at the O ring you will see a hole where an allen key can be fitted, tighten this up, it may be a bit slack

[Abcdavidson]

Looking at the O ring you will see a hole where an allen key can be fitted, tighten this up, it may be a bit slack

In the 1st Stage?

[Ian@1904]

In the 1st Stage?
http://i26.tinypic.com/2dirul5.jpg

[Abcdavidson]

Gotcha Ian, I'll try that.

Adam

[Abcdavidson]

http://i26.tinypic.com/2dirul5.jpg

Thanks again Ian, but it's tight as be damned. Still no joy..:confused:

[Twinsetmad]

I recon the problem is with the valve rather than the 1st stage.... as you haven't had a problem ever, using your 12ltr.:)

[Abcdavidson]

I recon the problem is with the valve rather than the 1st stage.... as you haven't had a problem ever, using your 12ltr.:)

But... I've tried a few other sets of regs on the new cylinder and they've been fine! :confused:

[ChristianG]

What have I done so far? I have tested my regs (although I was pretty sure anyway) on other cylinders to see if they were at fault. I have tested a few sets of club regs on my new cylinder and they are fine too! it just seems to be a compatibility issue with this one cylinder and one set of regs!

I have cleaned the 1st stage threads and inspected the cylinder threads, again both are fine. Then I changed the 1st stage 'o' ring, this is were the fun starts. After cleaning and setting the new 'o'ring I put it all together and ' 'voila' it looks like I'm good to go. I dismantle it and do it again to be sure, the leak has returned! I gave it another go, this time slightly wetting the 'o' ring and the leak is still there...
Intriguing.

The valve threads have absolutely nothing to do with leaking. It is the O Ring, and solely that, which stops leaks. Fingertight (no more than that) is perfectly adequate.

You've carefully inspected the channel in which the O Ring sits? Ditto the face of the tank against which it will rest? If either of these is "out" then there is the (highly unlikely) possibility of an intermittent leak.

[Nigel Hewitt]

OK I'll have a guess.
The central core is not fitting the cylinder.
Compare these two pictures
http://www.nigelhewitt.co.uk/diving/din7.jpg
http://www.nigelhewitt.co.uk/diving/din8.jpg
The top one, big core, is a 232bar din and the bottom one is 300bar.
The cylinder valves have matching holes in them. You will notice that Ian has a 232bar version in his picture.

The idea is that you can't screw a 232bar reg into a 300bar cylinder (big core into small hole) because it might be over pressurised and break but you can screw a 300bar reg into either.

I'm guessing that because of slop, damage or a manufacturing error the bits sometimes go together or sometimes don't. When they don't the system doesn't screw right down, the o-ring never reaches the bottom and it leaks. When the alignment works the core goes into the hole and the o-ring seals.

I'm going to guess you have a 232bar fitting in a 232bar cylinder and they are both on the limits. Try another cylinder or another reg and it's a better fit and works. Look for marks round the edge of the core or in the cylinder to indicate metal-to-metal contact.

Solution? Short term give it a wiggle before it tightens to get the central peg into the hole.
Long term find out if your regs will do 300bar and, if so, change the core. Most DIN regs do.

It's a guess. Nothing more.

[Abcdavidson]

Thanks for all the help guys. I think I'll have to make the trip to the dive shop and let them sort it. :)

Adam

[ChristianG]

Thanks for all the help guys. I think I'll have to make the trip to the dive shop and let them sort it. :)
Do let us know how it goes?

[Abcdavidson]

Do let us know how it goes?

I will for sure, it's being checked out tomorrow evening.

[GaryC]

I will for sure, it's being checked out tomorrow evening.
Would be interested on the result. Had a similar issue down at the pool tonight for one of the trainees who has just bought 300Bar DIN Apeks reg. It hisses on our brand new 10l 232 Faber bottle.
Changed the o ring no avail. Then it works ok. Then it doesnt. The reg worked ok on another bottle. The new bottle worked ok on another reg.

Very odd indeed.

Am I correct in thinking that there is no problem connecting a 300Bar reg to a 232Bar Bottle. (it is only the other way round that it wont work.)

Gary

[Michael Purcell]

OK so this is not the same problem but since it is fresh on my mind I thought I would say it. On the weekend a girl showed up with a brand new Cressi set. (A-CLAMP) Every bottle we tried it on it leaked. She was really mad because apparently she had the same problem the previous week and had taken back to the shop and they put it on several bottles and couldn't duplicate the problem.

It presented as a bent A clamp or bad o-ring (on the tanks of course) but was neither. It appeared to be the part of the reg that seats against the o-ring was an odd thickness and wasn't compatible with a lot of tanks.

I have seen this with some older ali tanks but these were standard tanks used by most dive shops. Anyone come across this sort of thing? Do you think it was just shoddy quality control or poor design? I can't imagine an entire line of regs suffering from this so I would imagine the former rather than the latter. Or perhaps something else?

[Gordon]

Am I correct in thinking that there is no problem connecting a 300Bar reg to a 232Bar Bottle. (it is only the other way round that it wont work.)



Shouldn't be any problems the sensible way round (300bar reg) - I've never had any.

G

[Ben Panter]

Hi Michael,

I've seen this before with a DIN insert - is that the scenario you're having problems with? Try changing the insert to one from another manufacturer.

A similar problem that sometimes occurs is when the frame section of the a-clamp is tapered and is too small for the converted DIN valve to fit in. This would probably be obvious though...

Cheers,

Ben

[Turtle Dude]

I appreciate this is not fixing the problem (which it is important to do); however, you may want to consider keeping a DIN to A-Clamp adapter handy if you are going on boat or holiday and using their cylinders.

Then if you find the issue again, one short term option, would be to swap to a 232 A-clamp tank and use the adaptor.

They are about £25-30 - better than losing a days diving.

http://www.divepursuits.com/prodimages/apeks_din_2_aclamp_l1.jpg

[Abcdavidson]

OK folks, I had the tank and regs inspected. a little taste of silicon gel on another new 'o'ring and a real good tighten up. It sealed fine :D The guy I was talking to said he had the same problem with his new cylinder initially. So when I disconnected and reconnected it was fine. Magically it appears to be fixed, I just have to tighten it up a little more than my other cylinder. Have to say I felt a wee bit stupid! :rolleyes:

[ChristianG]

OK folks, I had the tank and regs inspected. a little taste of silicon gel on another new 'o'ring and a real good tighten up. It sealed fine :D The guy I was talking to said he had the same problem with his new cylinder initially. So when I disconnected and reconnected it was fine. Magically it appears to be fixed, I just have to tighten it up a little more than my other cylinder. Have to say I felt a wee bit stupid! :rolleyes:
No, you're not stupid at all.

This leads me to think that the tap shank on your tank is a tad long. There is no way that you should have to grease this O Ring or tighten down the shank unnecessarily. No way at all. To my way of thinking this is not a solution, it is a work-around and I simply detest work-arounds, especially on life support equipment. Besides, grease does precisely nothing, note how I said that, to aid the integrity of any O Ring. All it does is come to the aid of O rings that have to move, as in shutter buttons on cameras. There is simply no point in adding grease to any O Ring that doesn't have to move, including these. Your LDS, therefore, has little idea of how these work.

Does your 1st stage work properly on other tanks with this tap configuration? Without the O Ring having to be greased or the shank unduly tightened? If yes, your (new) tank tap is the problem, simple as that. If your 1st Stage male shank is designed for 232 Bar tanks only (the short one) the tank tap's shank is too long (by a margin of rather less than 1mm) and needs to be replaced with the offending item tossed into the WPB.

If I'm right your LDS needs a proper talking to. If I'm wrong your LDS still needs a proper talking to - they have no idea about O Rings which to my way of thinking is just a tad towards criminal!

Whatever, your quest to fix the problem has not ended. Not no way, not no how.

[Adam Hunt]

Adam

How much air is in the tank, a full fill or is the tank near empty? I had a problem with a leaky valve at low pressure (new tank first fill). Pumped it right up and has been fine since.

Adam

[Abcdavidson]

No, you're not stupid at all.

This leads me to think that the tap shank on your tank is a tad long. There is no way that you should have to grease this O Ring or tighten down the shank unnecessarily. No way at all. To my way of thinking this is not a solution, it is a work-around and I simply detest work-arounds, especially on life support equipment. Besides, grease does precisely nothing, note how I said that, to aid the integrity of any O Ring. All it does is come to the aid of O rings that have to move, as in shutter buttons on cameras. There is simply no point in adding grease to any O Ring that doesn't have to move, including these. Your LDS, therefore, has little idea of how these work.

Does your 1st stage work properly on other tanks with this tap configuration? Without the O Ring having to be greased or the shank unduly tightened? If yes, your (new) tank tap is the problem, simple as that. If your 1st Stage male shank is designed for 232 Bar tanks only (the short one) the tank tap's shank is too long (by a margin of rather less than 1mm) and needs to be replaced with the offending item tossed into the WPB.

If I'm right your LDS needs a proper talking to. If I'm wrong your LDS still needs a proper talking to - they have no idea about O Rings which to my way of thinking is just a tad towards criminal!

Whatever, your quest to fix the problem has not ended. Not no way, not no how.

Thanks for the reply Christian, it wasn't my LDS that came up with the fix, it was a club member. Also the cylinder is interweb bought, so I can't really rant! But you are right, I have no problems on any other cylinders. Also, no other regs have a problem with my cylinder! :rolleyes: I'll speak to the retailer and suggest to them that they replace the tap. I was always pretty sure that I didn't need to horse the life out of it to get it sealed.

I will keep you updated!

Adam

[one_tc]

OK I'll have a guess.
The central core is not fitting the cylinder.
Compare these two pictures
http://www.nigelhewitt.co.uk/diving/din7.jpg
http://www.nigelhewitt.co.uk/diving/din8.jpg
The top one, big core, is a 232bar din and the bottom one is 300bar.
The cylinder valves have matching holes in them. You will notice that Ian has a 232bar version in his picture.



I can't quite see the top image, but they both look like they are 7 threads on the DIN. Is this the case or has the top one (232 bar) only 5?

:)
Tim

[one_tc]

I appreciate this is not fixing the problem (which it is important to do); however, you may want to consider keeping a DIN to A-Clamp adapter handy if you are going on boat or holiday and using their cylinders.

Then if you find the issue again, one short term option, would be to swap to a 232 A-clamp tank and use the adaptor.

They are about £25-30 - better than losing a days diving.

http://www.divepursuits.com/prodimages/apeks_din_2_aclamp_l1.jpg


From my experience Apeks yoke connectors are very prone to leaking when attached over cheap foreign DIN inserts. I now take my own inserts on holiday with me. If you look at an Apeks or MDE insert the face is pretty much flush, but alot of the cheap inserts the O ring is recessed.


Does anyone know what make the valve was that was causing the problems?
:)
Tim

[Twinsetmad]

On the top picture the 232bar din fitting.. the center bit inside the O ring is larger and flatter than the the 300 bar fitting below.

Look inside your cylinder valve and you will see a hole or orifice at the back of the valve that this bit fits in...

300bar din has 7 turn threads.
232bar din has 5 turn threads.

I think the suggestions are that this part of the din fit is not locating properly in the valve and bottoming out before it seals on the O ring.

[Nigel Hewitt]

I can't quite see the top image, but they both look like they are 7 threads on the DIN. Is this the case or has the top one (232 bar) only 5?
A 7 thread din wheel works well with a 5 thread pillar valve but the key here is the center core which is wider on a 232 bar DIN fitting. Both the fittings in the photographs happen to have seven thread wheels.

I believe the 7 turn body of the 300bar fitting was an improvement while the narrower but deeper core is the actual interlock key. Most people seem to assume that the fact that a five thread wheel of the 232 won't screw down and seal in a 7 turn 300 is the key while in fact it is just a structural feature as the standards body recognised that wheels are just too easy to change.

[Twinsetmad]

http://i26.tinypic.com/2dirul5.jpg
This picture is a 232bar din fitting... the center of the din fit is bigger and flatter than that of a 300bar din.