TSandM:
Thanks, DA Aquamaster. If there is a regulation that says this burst disc is the wrong one, then I understand the dive shop wanting me to change it, and I feel a little better. I wonder about having it come with the wrong disc, though . . .
A 5250 psi burst disc would work for a 3AA or 3AL tank with a service pressure of 3300 psi or 3441 psi. and would be ideally suited for an exempt tank with a 3500 psi service pressure and a 150% test pressure.
When tank valves are shipped by the manufacturer they come equipped with a particular burst disc matching the particular service pressure the valve is ordered for. My guess is that whoever assembled the order at Scubatoys packaged the tank with a valve intended for a 3300 psi, 3441 psi, or 3500 psi pressure tank and figured it would be close enough. In some cases, it would pass unnoticed as not every dive shop or end user would dissasemble the assembly and check it, unless the valve itself is marked for something other than a 3000 psi service pressure (and some valves are).
It is surprising though as it is very un-Larry like for that to happen.
1_T_Submariner:
Sounds like they are being overly picky. Wonder what the tolerance on the burst disk rupture pressure is? 5250 +/- ???Psi
The 10% under test pressure range exists so that the burst disc will fail between the test pressure minus 10% up to but not exceeding the test pressure.
So for a 3000 psi service burst disc, the disc will fail in a range between 4500 and 5000 psi (when new anyway.) and for a 5250 psi burst disc intended for a 3500 psi service pressure tank, it will rupture between 4725 and 5250 psi.
Would it make a difference? Probably not, but it is not technically legal.
lamont:
sounds like you are being punished for buying it from scubatoys...
That is possibly true, but would still not be all of the problem. It is not uncommon at all for local dive shops to get picky about stuff not purchased in their shop and the reasons are not all related to just being miffed that the customer bought the item elsewhere.
When a customer comes in with an internet/ebay purchase or even wit an item purchased from another dive shop, the shop does not really know what may have happened with the items since they left the factory or wholesaler and it is just prudent to check to see that things are properly configured.
In this case from the shop's perspective, the valve could have come with a burst disc designed for 2250 or even 1800 psi. and a burst disc designed for an 1800 psi tank would rupture at 2700 to 3000 psi. creating a potential out of air situation for the customer if the valve was used on the 3000 psi pony bottle. Consequently it would have created a liability issue for the shop if they did not check to ensure it was correct. Once they checked the disc and discovered it was incorrect, they would then have had liability and DOT compliance issues if they let the tank out of their shop and placed it in service with a burst disc that was known to be incorrect. Either way they would have been hanging out there liability wise if they had not checked and something had happened.
It is after all life support equipment and our tendency as divers to be very comfortable with it, and as a result more than a little complacent, does not change that fact.
