Pony freeflow

[ZenDiver]

Yes, I already know about the causes of freeflows, and that is why I didn't ask about them, or how to handle them, or which mounting method was better. I was asking about the frequency of freeflows for those using backmounted ponies, without judgment or criticism.

Over 200 dives with a back mounted 19 ft3 pony and only had a free flow once from a second stage problem. I noticed the failure mid way through dive and aborted the dive. The problem was the the cracking pressure was too sensitive although I had not changed it for the last 50 dives which leads me to believe that it was just something that came out of adjustment over time and since then have checked cracking pressure on every dive since with pony bottle. I place the pony second stage in the triangle so that I can notice a freeflow.

If you have a tank oring go while underwater I would be surprised if you dont hear it. Usually makes alot of racket and most everyone within a 20 foot radius will notice as well. In over 700 dives I have never had this happen to me and with the 1000 plus divers I have dived with and taught over the years I can only recall this happening once underwater. Usually happens at first pressure up on the surface before dive. This has happened several times that I can think of. This is why I advocate pressurizing your tank at the dock or within 15 to 20 minutes of a dive.

I have witnessed three 1st stage failures with divers. Two failed in the open position releasing pressure through the second stage with tremedus force, easily noticeable from a simple second stage failure due to cracking pressure or other problem. One failed in a closed position completly shutting down and did not deliver any air. Diver had to make a ESA from approx 60 feet and survived with no injuries. I was not close enough to him to assist and his buddy followed closely behind. There was 2600 psi in his tank and his reg completly siezed up. Not sure what happened as I did not work on it after the dive. The two that failed in the open position were related to a broken oring in the inner body. Not common but a remote possibilty.

So if you take in to account my own personal dives (over 700) and that of the divers diving with me (probably in the thousands) the failures seem to be remote. 1 personal failure related to second stage failure, 1 tank oring failure, 3 first stage failures and 4 or 5 HP hoses bursting either at the 1st stage connection or where the SPG and hose connect, or the hose itself. These numbers reflect warm water diving and not necessarilly with a pony bottle when I referred to the tank oring problems, 1st stage problems and HP hose failures.

 

[Dive Junky]

To answer your question simply. I have over 200 dives in cold water with a backmounted pony and have never had a free flow. Just treat it like your main reg as far as quality and maintenance and it won't act any different as your primary.

Also in addition to mounting it on your chest try attaching a SPG and wire tie it to your back-up. This way you can check it periodically for any slow leaks that you might not notice in the first stage and if you have the same reg for your back-up and primary you won't suck your pony dry before you realize you have the wrong one in your mouth.

Dive safe have fun