DIN o-ring question

[ScubaSloan]

I just did a dive this weekend where I had a slight burst of air leak from the first stage when I turned the tank on. On my DIN regulator, I did a quick check of the o-ring, looked fine, then when I turned on the air, there was a quick pop but then nothing. Reg breathed fine, no further leaks. When I pulled the o-ring out it had a crease in it. Looked to me like the o-ring was not sitting properly and when it pressurizing a seal was formed but part of the o-ring was caught. My gut is this would have breathed fine under water but I changed it to be safe. Did I just not check it well enough? Has anyone else had this happen?

 

[ScubaDocER]

It can and does happen a bit. My DIN regs have done the same thing. If the o ring is not seated properly or comes out a bit, then there is not a good seal between it and the valve and you get a leak. You did the right thing in checking the o ring and detecting the crease. Replace any questionable o rings and remember to check the o ring before securing it to the valve on future dives. I have had that happen to me and after positioning the o ring in the DIN connector, the problem resolves pretty quickly. You did well. Take it as a learning lesson to always check that o ring.

 

[uksub]

I once had an o-ring 'pop' on my DIN regs, but it was the internal one that blew, and it just kept pi~~ing out air.....good job I was only pool training, and not at depth!!

 

[GrandpaScuba]

You should also check the DIN fitting. Most regs, the DIN fitting is screwed into the reg body after the yoke nut and yoke have been removed. While the DIN handwheel turns freely while you are attaching the reg to the tank, once the tank has been turned on and the reg presurized, the DIN handwheel and fitting are "locked" by pressure.

If you or someone lifts your unit by the reg, at this point, and maybe twists just a little, the strength of this pressure lock can provide enough leverage that you can loosen the DIN fitting from the reg. Do this enough times, and one day, when you turn on your tank, suddenly you will have air escaping from the 1st stage. When this happens, you need to get the propper wrench and tighten it back up.

If you have a DIN regulator, it's a good idea to carry this wrench with you in your save-a-dive kit. For many DIN regulators, it's a 6mm allen wrench. For Scubapro, it's a smaller allen wrench, but I can't remember the size, but I think it's like 3mm.

It's a good idea, if you dive DIN, to check that the DIN fitting is correctly tightened on the reg at the start of each day of diving.

 

[Gombessa]

I used to have this happen as well. Everything was seated properly so I think it had to do with having the wrong o-ring size on the first stage - there are a couple of "REALLY SIMILAR but different" o-rings and regs use one or the other. After replacing the o-rings, it hasn't happened since.

 

[String]

Happens a lot with some first stages. Ive seen lots of Mares ones hiss for 1/2 second then seal. All is fine on the dive then (although id quit diving before being forced to dive with Mares regs myself!).

 

[DA Aquamaster]

If you have a DIN regulator, it's a good idea to carry this wrench with you in your save-a-dive kit. For many DIN regulators, it's a 6mm allen wrench. For Scubapro, it's a smaller allen wrench, but I can't remember the size, but I think it's like 3mm.

Scubapro also uses a 6mm allen wrench. To torque it properly you need a torque wrench and a long reach 6mm allen head socket.

In the field an allen wrech would be fine as an emergency measure and you'd be hard pressed to greatly exceed the 22 ft pound torque specification for the DIN retainer.

The Scubapro reg looks like it needs a smaller wrech for the retainer as a standard 1/8" allen wrench (the same one you use for LP and HP ports) is needed to remove the part that retains the o-ring and the filter underneath it. Once those are removed, you can access the 6mm fitting in the DIN retainer.

Using the separate part to retain the o-ring is nice as it is deeply grooved to hold the o-ring in place around the fitting, and when you install it in the DIN retainer, it is very difficult for the o-ring to become unseated - helping to prevent the problem that can occur in other designs.

 

[ScubaSloan]

This is an apeks XTX50. Just got it serviced and had never had it happen before.