Hi All - my recently purchased Scubapro Mark25 Evo reg still says in the manual to gently purge the second stage when opening the cylinder. I thought that practice was now obsolete - would appreciate any guidance. Thanks
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I thought the reason to gently purge while turning on the gas was to prevent a pressure wave (like a water hammer) from harming the seat.You'll get lots of advice here on SB about a thing called IP, or Intermediate Pressure. It's the pressure delivered to your second stage by your first stage, which steps down 3000 psi to about 135 psi.
Since most divers don't check their IP regularly, they don't have advance warning of an oring failure which would allow IP to go way past safe limits for your hoses and second stage mechanism. Checking IP stability can help you see some problems in advance.
That being the case, Scubapro's advice vents the first stage, so that if there were a catastrophic internal failure, it would be suggested by abnormal air flow during those initial moments of venting, allowing you to turn the tank back off before you blew a hose or broke apart the parts inside the second stage.
Pretty conservative advice, given the general safety of well maintained gear. But not bad advice.
Better advice? Read and follow @couv 's checklist here:
Regulator Inspection and Checklist (Rev-8)
Many thanks allHi All - my recently purchased Scubapro Mark25 Evo reg still says in the manual to gently purge the second stage when opening the cylinder. I thought that practice was now obsolete - would appreciate any guidance. Thanks
I thought the reason to gently purge while turning on the gas was to prevent a pressure wave (like a water hammer) from harming the seat.