Reg flow adjustment

[grf88]

Is this for those new-fangled first stages with an external adjustment for IP? I'm not clear on what 'correct' IP is. Actually, I'm not sure what correct cracking pressure is either. Optimal cracking, yes, largely a matter of preference and conditions. I use my IP gauge to determine the working order of my first stages, things like instant return and possible creep. As long as the IP falls in the proper range for a specific reg and stays there, no problem.

As you well know the IP is not adjusted by the 2nd. stage but why set the cracking pressure if the IP is not set to factory recommended setting. His regs have just been serviced and are freeflowing, what is the chance they didn't cycle the 1st. stage after service. Handy to know that the 1st. stage is set to the correct IP, which for the record is within the range recommended by the manufacturer. Some like to measure the cracking pressure at the exact point where the IP drops and the gauge is helpful for that. To my mind mind correct cracking pressure is that which is suitable for the conditions but that is just semantics, are you in need a hug or something.

 

[Lorenzoid]

While setting up for a dive, I had a second stage that refused to stop free-flowing. My first inclination was to disconnect the second stage and turn the adjustment screw in a tiny bit. I had a multi-tool with the correct size hex key for that. But I didn't have an IP gauge with me. I reconnected the second stage, but it was still free-flowing. After another try I realized it must be that the IP had risen too high, and no amount of second stage adjustment was going to stop the free flow. Back home, I connected an IP gauge, and sure enough I saw that the IP climbed and climbed--way above the manufacturer's specified IP--until the second stage free-flowed. A sign the reg needed servicing.

 

[agilis]

As you well know the IP is not adjusted by the 2nd. stage but why set the cracking pressure if the IP is not set to factory recommended setting. His regs have just been serviced and are freeflowing, what is the chance they didn't cycle the 1st. stage after service. Handy to know that the 1st. stage is set to the correct IP, which for the record is within the range recommended by the manufacturer. Some like to measure the cracking pressure at the exact point where the IP drops and the gauge is helpful for that. To my mind mind correct cracking pressure is that which is suitable for the conditions but that is just semantics, are you in need a hug or something.

Hugs were out before I got my second Moderna shot, so I've learned to do without. Have people even begun shaking hands again?
If the first stage IP is off, that is a far more serious issue than cracking pressure, a relatively simple adjustment, and not a serious problem like an IP off specs. Too inclined to free flow or too high a WOB are about it for second stage adjustments of that sort. As I just wrote, cracking pressure is a matter of personal preference and conditions, but IP is not. In any case the exact IP is not too important, as long as it's within the parameters appropriate for that first stage. What, btw, is the difference between the exact point where the IP drops and the cracking pressure? I'm always interested in learning new stuff. The only adjustment to IP that I know how to do involves shims.

 

[Open Ocean Diver]

Hugs were out before I got my second Moderna shot, so I've learned to do without. Have people even begun shaking hands again?
If the first stage IP is off, that is a far more serious issue than cracking pressure, a relatively simple adjustment, and not a serious problem like an IP off specs. Too inclined to free flow or too high a WOB are about it for second stage adjustments of that sort. As I just wrote, cracking pressure is a matter of personal preference and conditions, but IP is not. In any case the exact IP is not too important, as long as it's within the parameters appropriate for that first stage. What, btw, is the difference between the exact point where the IP drops and the cracking pressure? I'm always interested in learning new stuff.

Cracking pressure is the effort it takes to open up the second stage valve one way to measure is by monitoring the IP at the same time your reading the pressure, when the IP dips that’s where you take your measurement... when the valve opens the IP will drop or not as precise you can listen for the valve to open and take your measurement then.

 

[agilis]

While setting up for a dive, I had a second stage that refused to stop free-flowing. My first inclination was to disconnect the second stage and turn the adjustment screw in a tiny bit. I had a multi-tool with the correct size hex key for that. But I didn't have an IP gauge with me. I reconnected the second stage, but it was still free-flowing. After another try I realized it must be that the IP had risen too high, and no amount of second stage adjustment was going to stop the free flow. Back home, I connected an IP gauge, and sure enough I saw that the IP climbed and climbed--way above the manufacturer's specified IP--until the second stage free-flowed. A sign the reg needed servicing.

I recently bought $10 IP gauge that instantly attaches to and detaches from the BC air hose. A 20 second check. It reads the same as my more elaborate IP gauge.

 

[grf88]

The OP has just had his regs serviced and they are free flowing. Maybe it is just me but before doing anything else I would check the IP to make sure it is correctly set. If they did not cycle the 1st. stage after service it it quite likely that the IP is wrong. I probably do not know much about piston 1st's but I m sure they can be out after service if not cycled but maybe I am wrong as my experience is with diaphragm 1st. stages which do not use shims to set IP. If it is not between parameters setting the cracking pressure is not that much help. Some people like to see the moment the IP drops when setting the cracking pressure to get a better idea of the exact setting. I suggested a hug as you seem to be unnecessarily confrontational today. No I don't think handshakes will be returning anytime soon.

 

[agilis]

Cracking pressure is the effort it takes to open up the second stage valve one way to measure is by monitoring the IP at the same time your reading the pressure, when the IP dips that’s where you take your measurement... when the valve opens the IP will drop or not as precise you can listen for the valve to open and take your measurement then.

I see. I always thought the IP dropped when the second stage valve opened. Pressing the purge is obviously not the same as inhaling against a closed valve, and the work of breathing to open that valve is difficult to measure with precision, various measuring devices not being quite the same thing. Different regs with the same cracking pressure can have a very different subjective feel. Consider the wondrous Scubapro D series. I've spent many hours on my back under ledges with my D350, something I would not have done with a more conventional second stage with an equivalent cracking point.

 

[Raphus]

I am sure it's the cracking pressure, because it's not free-flowing on its own by just leaving it attached.
It needs a "trigger" like water flow.
It just breaths way to easy even in predive and adjustment knob all the way to minus.

I will get the ip gauge, planned to do it anyway and the I line adjustment tool with the ip gauge seems like a good investment

 

[agilis]

The OP has just had his regs serviced and they are free flowing. Maybe it is just me but before doing anything else I would check the IP to make sure it is correctly set. If they did not cycle the 1st. stage after service it it quite likely that the IP is wrong. I probably do not know much about piston 1st's but I m sure they can be out after service if not cycled but maybe I am wrong as my experience is with diaphragm 1st. stages which do not use shims to set IP. If it is not between parameters setting the cracking pressure is not that much help. Some people like to see the moment the IP drops when setting the cracking pressure to get a better idea of the exact setting. I suggested a hug as you seem to be unnecessarily confrontational today. No I don't think handshakes will be returning anytime soon.

There is a problem, not mine, when a question is considered confrontational. I mean, we're not in church here. This is not a transubstantiation versus consubstantiation theological argument. I only asked what the purpose of the IP gauge was on a second stage adjustment tool, and inexplicable defenses arose. Are you selling these things? Constantly using the 'hugs' imagery is an an attempt to ridicule, to demean. I suspect you ate the wrong things for lunch and are suffering from unpleasant bowel issues. Don't take it out on me.

 

[grf88]

There is a problem, not mine, when a question is considered confrontational. I mean, we're not in church here. This is not a transubstantiation versus consubstantiation theological argument. I only asked what the purpose of the IP gauge was on a second stage adjustment tool, and inexplicable defenses arose. Are you selling these things? Constantly using the 'hugs' imagery is an an attempt to ridicule, to demean. I suspect you ate the wrong things for lunch and are suffering from unpleasant bowel issues. Don't take it out on me.

Try re-reading this:

Is this for those new-fangled first stages with an external adjustment for IP? I'm not clear on what 'correct' IP is. Actually, I'm not sure what correct cracking pressure is either. Optimal cracking, yes, largely a matter of preference and conditions. I use my IP gauge to determine the working order of my first stages, things like instant return and possible creep. As long as the IP falls in the proper range for a specific reg and stays there, no problem.