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namabiru
07-13-2008, 00:32
So last weekend I hooked my kit up and turned the air on, only to discover that my SPG hose is leaking. This is a fairly new Tusa SCA 240-T gauge bought from ST in April, and only used on perhaps 20 or 30 dives. I figured out, by trial and error, that the leak is coming from where the SPG connects to the hose. Last weekend I was able to take a crescent wrench and tighten the connection; however, 2 days ago I had the same problem but was unable to tighten the connection. Needless to say the SPG got swapped out and hasn't been in the water since.

Is this just maybe an O-Ring that's gone off and needs switching? Or is it evidence of a faulty gauge or a faulty hose?

For the record, the SPG has never been dropped, or banged off any surfaces underwater. It's been rinsed after each dive day. There were no precursors warning me of impending doom, such as dodgy air reading or gauge going off the charts.

What concerns me, I suppose, is that this *is* a fairly new gauge.

navyhmc
07-13-2008, 05:04
Take the SPG off the HP hose. There should be a small tube with two small o-rings on it. IF you have access to o-rings of that size, switch those out and see what happens from there. IF you can't do this, I hate to say it, you will have to send it off for service.

namabiru
07-13-2008, 05:32
Yeah, it's what I figured. We'll see what happens.

keyshunter
07-13-2008, 07:09
The most frequent cause of leaks in that area is the o-rings on the HP spool which resides in the connection between the hose and spg. Replacing these small o-rings (most use 003) usually solves the problem. Be sure to lubricate the o-rings.

awap
07-13-2008, 08:39
Over tightening a scuba gear connection is probably one of the best ways to cause expensive damage. And it is ineffective as even finger tight connections are sufficient to allow o-rings to seal. You probably just repositioned a bad o-ring enough to temporarily make the seal.

The o-rings on that connection are size 2-003. I prefer duro 70 as they are easier to install. Viton is probably the material of choice but EPDM or even nitrile should work fine. I'd look carefully for corrosion or a salt deposit that may be causing the premature damage to that o-ring. And you do need to lube those o-ring and the associated surfaces pretty good as the o-rings are dynamic and the surfaces are vulnerable to corrosion. Hours of soaking after SW dives are required to dilute the salt.

cummings66
07-13-2008, 16:22
Plus the easy way to change the O ring is to take the spool and set the O ring on a soft surface, I use a place mat my daughter eats on, lube the O ring and set it on there. Then I take the spool and place on it and push down, it snaps right in place with absolutely no fuss.

awap
07-13-2008, 16:31
Plus the easy way to change the O ring is to take the spool and set the O ring on a soft surface, I use a place mat my daughter eats on, lube the O ring and set it on there. Then I take the spool and place on it and push down, it snaps right in place with absolutely no fuss.

I use my other hand. Key is a cushioned readily available surface. Just stab it right on.

Black-Gorrilla
07-13-2008, 21:25
Plus the easy way to change the O ring is to take the spool and set the O ring on a soft surface, I use a place mat my daughter eats on, lube the O ring and set it on there. Then I take the spool and place on it and push down, it snaps right in place with absolutely no fuss.

i used to play paintball alot and was a tech at a local well know shop (there are some pieces with similar design as that spool and some even smaller) and have never thought to do it that way... it's just so obvious that it would work that i always took the hard way of doing it with one hand holding the spool and one hand putting the o-ring on... Thanks for sharing the easier way :)

namabiru
07-13-2008, 23:35
Everything sounds good here! We should assemble our own fix-it-yourself guide on here.

In this case, as I don't have any lubricant for o-rings, and I have business in the proximity of a dive shop, I may just take my SPG in and give the techie 20 riyal to do it for me.

namabiru
07-16-2008, 10:39
Well, as it turns out, it is the hose itself that is faulty. The dive shop tried replacing all 3 O-rings, but same same.

navyhmc
07-16-2008, 17:37
Sorry to hear that. At least now you know. Hope you geta new HP hose soon.

awap
07-16-2008, 18:18
Well, as it turns out, it is the hose itself that is faulty. The dive shop tried replacing all 3 O-rings, but same same.

Exactly where was the leak coming from. Was it coming from the rubber hose, from between the rubber hose and the crimped metal connection, or from between two metal parts on SPG connection? I suggest you retrieve the 'bad' hose also. It may well be salvageable with a little careful cleaning.

namabiru
07-17-2008, 00:57
It was at the hose to gauge connection.

I've e-mailed ST about this, and asked about the cost of a replacement hose since I didn't see one on their website. Joe agreed that a hose going wonky after 35 dives max isn't right. So the gauge is going back to the States. Either the hose will be replaced and sent, or the whole gauge.

Nice!

awap
07-17-2008, 08:59
It was at the hose to gauge connection.

I've e-mailed ST about this, and asked about the cost of a replacement hose since I didn't see one on their website. Joe agreed that a hose going wonky after 35 dives max isn't right. So the gauge is going back to the States. Either the hose will be replaced and sent, or the whole gauge.

Nice!

That connection leaks because gas is leaking by one or both the o-rings that make the seal. If the fault is not with the o-rings, then the next suspect is the seating surfaces. A good cleaning and inspection of the spool, and the hose and SPG seating surfaces would likely fix the problem. There could always be some defect in the seating surfaces which may require replacement of the spool, hose or SPG. Spools are cheap. By a process of elimination, a shop should be able to work their way to the defective component if it is the hose or SPG.

namabiru
07-18-2008, 06:01
Makes good sense. At least I know the problem wasn't anything I did wrong, and that it can be fixed without me having to purchase another gauge.