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EHowe
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Leaking Sel Pac manifold

Sat Feb 03, 2018 2:17 pm

My current dive rig consists of Faber steel mini doubles (50’s) with a Sherwood Sel Pac dual outlet manifold, VDH BP/W, Hot DAAM (cyclone,HPR the works) and a Conshelf IV that runs SPG & inflator. Love this setup. Works awesome with a DH, offers some redundancy and is great for testing different regs since I always have a backup. Got a message yesterday from an LDS that have my tanks into for hydro/vis stating that my valve is leaking. I rebuilt both valves 3 years ago when I originally bought tanks and have never had any problems. Guy that called won’t be in until Monday so I don’t know specifics yet, but it sounds fishy. Any leak in the valves them selves should be an easy fix. The cross bar connections are what worry me. Any ideas on what I should be on the lookout for?

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luis
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Re: Leaking Sel Pac manifold

Sat Feb 03, 2018 6:19 pm

Any kind of lubricant or any other contaminants in the metal to metal seals (in the cross bar) can cause a small leak, even some silicone spray can do it. You have to make certain that both surfaces are very clean and dry.

After I get a good seal in that joint I actually avoid ever taking that joint apart. To do VIP or any service I just remove the cylinders just like if it was a solid manifold. It is actually quick and easy to just spin the cylinders off from the manifold without breaking apart the manifold.

Good luck
Luis

Buceador con escafandra autónoma clásica.

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antique diver
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Re: Leaking Sel Pac manifold

Mon Feb 05, 2018 9:31 pm

I'm seldom surprised when a dive shop can't get a manifold to seal. If it is at the union sometimes described as "ball and socket" type seal, there could be slight damage to some part of the metal-to-metal seal. I have dealt with that frustrating issue on one that I could not get to seal by shaping thin copper washers to fit into the ball and socket unions. If you have an issue with that and can't resolve as Luis suggests, I have these available, pre-shaped as shown:
IMG_3038.JPG
If you are handy with tools, I would bet that you could do a better job of assembling your own manifold.
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"I get plenty of excercise just pushing my luck!"

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EHowe
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Re: Leaking Sel Pac manifold

Tue Feb 06, 2018 10:29 pm

Thanks for the replies. I finally spoke to the guy at the shop and he states it is the cross bar leaking. When I get it home I'll investigate a little closer. Before using copper washers would it be advisable to try resurfacing ball with ultra fine sandpaper?

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antique diver
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Re: Leaking Sel Pac manifold

Wed Feb 07, 2018 1:19 am

EHowe wrote: Thanks for the replies. I finally spoke to the guy at the shop and he states it is the cross bar leaking. When I get it home I'll investigate a little closer. Before using copper washers would it be advisable to try resurfacing ball with ultra fine sandpaper?
I'm concerned that may make uneven spots and worsen things. Try cleaning the ball and socket joints real well with soap and water mix, and look for gouges or scratches. You may have better luck with the assembly than the shop did, so give it another try. If all else fails, as was the case with one of mine, the copper washers are soft and can't damage anything.

Also, I am not familiar with the connecting parts on the Sherwood manifold, and don't know if it's like the USD ones I was thinking of. Some use oring seals in the ends instead. Open yours up and check that out, then try a careful reassembly. Snug them up with the bands loose with tanks on a flat and level surface. Snug the bands a little then tighten the manifold more.

Email me for phone number if you want to discuss in detail when you get ready to assemble.
"I get plenty of excercise just pushing my luck!"

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luis
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Re: Leaking Sel Pac manifold

Wed Feb 07, 2018 11:20 am

I agree with not using any sand paper. I can only see that making it worse.

As mentioned, I would clean it very well. You could use alcohol on your final whipping.

The connection design on the Sherwood is the same as the US Divers, but it is just a different size. One uses the CGA (Compress Gas Association) oxygen standard fitting and the other uses the CGA air standard fitting (the same fitting used on fire fittings SCBA).

I am pretty sure that US Divers uses the CGA oxygen fitting and Sherwood uses the CGA air fitting, but I may have it backwards.

The Sherwood fitting is a bit bigger than the US Divers fitting.

The SCBA fittings has actually evolved were they have added an O-ring groove onto the male nipple side of the fitting. So the same exact fitting will work in a metal-to-metal seal or you can find the newer ones incorporating a groove for an O-ring seal, in what is almost a face seal. The two types of seal are interchangeable. But you can hand tighten the O-ring seal nipple versus needing a wrench for the metal-to-metal seal.

Actually the SCBA fittings also now comes with two different length of nipples. The two variations are designed to prevent the newer high pressure systems to be mixed with low pressure bottles. The new high pressure bottles are 4500 psi. The older bottles are 3000 psi.

I have often though about asking a machinist to add an O-ring groove to the male nipples on my Sherwood manifolds. It should not be that hard and it would make the connection much easier to seal.

BTW, this is one of those few connections that you can try tighten it as much as you can, and that can. Unless you are a huge gorilla, you can’t hurt it (if the joint was clean) by over-tightening it, but it can help.
Luis

Buceador con escafandra autónoma clásica.

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luis
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Re: Leaking Sel Pac manifold

Wed Feb 07, 2018 7:19 pm

I believe that Sherwood uses CGA 346 and US Divers uses CGA 540, but I have not confirmed it.

The CGA 346 is the air fitting and CGA 540 is the O2 fitting (shown second).
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Luis

Buceador con escafandra autónoma clásica.

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EHowe
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Re: Leaking Sel Pac manifold

Wed Feb 07, 2018 8:50 pm

I’m no gorilla that is for sure. :D I like the idea of losining the bands before tightening the manifold, didn’t think of that and I can see how having tanks slightly out of alignment would cause a problem. I brought them home today along with my new drysuit. I’ll head out to the garage tomorrow and try your suggestions and let you know if I have any luck.

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EHowe
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Re: Leaking Sel Pac manifold

Fri Feb 09, 2018 8:35 am

I loosened tank bands, cleaned the connections real good and cranked it down as tight as I could. I was able to transfill to around 1800 PSI with no leaks. I usually pump these tanks to 3000 so I will see what happens when I get a chance to fill them all the way. But, as of now it seems good. I don't think the guy at the shop put put much effort into it. I think he reassembled the tanks and found the leak when he tried to fill them and that was it. I will probably give Bill a call and see about a couple of those copper seals just to have them on hand. Thanks for all your advice :D

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antique diver
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Re: Leaking Sel Pac manifold

Fri Feb 09, 2018 9:52 am

Good job, Ed!
"I get plenty of excercise just pushing my luck!"

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