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Post by mackintoshman on Apr 7, 2023 6:56:54 GMT -8
So my question is. What IP pressure at what tank PSI. 500, 2250 or 300 and the PI for each. Mac.
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Post by nikeajax on Apr 7, 2023 7:37:31 GMT -8
It's my understanding, you want to set your IP with 500-psi in your tank, for best end result, and 135 for best efficiency/performance characteristics JB
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Post by artc on Apr 7, 2023 8:24:00 GMT -8
Hi mackintoshman. Here’s what I go by.
500. - 135psi
300 - 138psi
2250 - 110psi
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Post by SeaRat on Apr 7, 2023 8:38:26 GMT -8
So my question is. What IP pressure at what tank PSI. 500, 2250 or 300 and the PI for each. Mac. The U.S. Navy Diving Manual, March 1970, states: "Full cylinder pressure" for the Navy at that time with the Navy AL 90 tanks was 3000 psi. This would lead to a IP when the pressure was down to 500 psi on the tanks to somewhere around 130-140 psi. Now, at the U.S. Navy School for Underwater Swimmers, we were taught an alternate method which doesn't use a pressure gauge. That was to put the DA Aquamaster onto a set of tanks at 500 psi, and adjust the pressure until a slight leakage occurred. That back it off about 1/4 turn with the Allen wrench. If it held, then that would allow the diver the easiest breathing over the full range of the tank pressure. John
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Post by herman on Apr 8, 2023 3:36:10 GMT -8
Being an unbalanced diaphragm first stage, you set the IP with a low tank pressure (300-500) and take whatever you get with a full tank- it will be lower. Counter to what you would think, as tank pressure drops, the IP actually rises, this is NORMAL for an unbalanced diaphragm reg (the opposite of a piston reg). So if you set the IP with a full tank, odds are pretty good it will free flow when the tank gets low due to higher than expected IP (since it went up as tank pressure fell). The older manuals say to set the IP with a 300psi tank to 110psi, personally, I set IP around 135 just to keep consistent with all my other regs. The exact number is not really critical, what is important is you set up the second stage to handle the max IP it will see (which will be at low tank pressures).
If you are working on a RAM, then things change a little since it is a balanced diaphragm first stage. While the IP stays a lot closer to the same as tank pressure chances, it none the less does change some, balancing is never perfect. YOU should see less swing on a RAM but still some so setting one up with a low tank is still the best since the IP will move upwards as tank pressure changes, just not as much due to the effects of balancing the first stage.
One more thing to keep in mind. When you are adjusting the second stage, one of the 3 holes in it MUST face the horn, otherwise the venturi will not work properly and the reg will not breath anywhere near as good....it will work, just not well. The proper way to start setting it is to install the second stage screwed in fully, NOT with a wrench-hand tight, then back out to align the first hole you come to. This is your starting place, you may have to tweek IP down if it free flows or back to another hole to get the setting to it's best setting. This is more experience than anything so setting it a little tight is the best option when learning to adjust them.
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Post by mackintoshman on Apr 8, 2023 5:56:56 GMT -8
thanks everyone, This is great info. Herman, I thought you adjusted the second stage by turning the nut, this is not correct?
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Post by james1979 on Apr 8, 2023 6:52:14 GMT -8
thanks everyone, This is great info. Herman, I thought you adjusted the second stage by turning the nut, this is not correct? I'm not herman, but the second stage nut is used to set lever height. Adjusting the second stage body out reduces the spring pressure (lightening the cracking pressure).
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Post by vance on Apr 8, 2023 7:56:15 GMT -8
thanks everyone, This is great info. Herman, I thought you adjusted the second stage by turning the nut, this is not correct? I'm not herman, but the second stage nut is used to set lever height. Adjusting the second stage body out reduces the spring pressure (lightening the cracking pressure). OK, I'm jumping in. Some of this has already been mentioned. The second stage body is not supposed to be screwed down tight, and one of the 3 holes must point down the intake horn. You want the second stage backed out as much as possible without leaking in order to achieve the least cracking effort. You may need to tighten it slightly if you get freeflow in the water.The small 5-40 nut on top of the second stage lever should be screwed down so the lever does not have any slop, but does not cause the poppet to leak. Lever height should be correct without slop. It might require bending, but usually not. Make sure the retaining ears do not get torqued when tightened. The lever should move very easily. You don't need to twist the ear tops or use thread lock on the ear screws. If the ears are twisted, carefully straighten them so they don't inhibit the lever movement. If the lever tips and/or diaphragm tabs show wear, clean them up with a file and/or fine emery cloth. Be sure your diaphragm is square to the tips when installing. Sometimes the lever will drop a bit when put on the tank and pressurized. Take up the slack while it's under pressure. Be sure to use a locknut, or use nail polish on the nut after adjustment. Also, glue your soft seat in the poppet. I have had the blue ones come out and get stuck in the volcano!
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Post by herman on Apr 8, 2023 17:44:46 GMT -8
The second stage is screwed down completely (finger not wrench tight) then backed out as necessary for correct cracking pressure (after IP is set). I screw it in completely, set IP with a low tank, back the second stage out until it starts to free flow then back in to the next hole. Don't be too skimpy going back in since the seat will take a set after a while and start leaking if you do. The lever height is set using the nut. I prefer to leave about 1/8 between the diaphragm and the lever, as the diaphragm will close the gap some when it is clamped down and the lever will rise some as the LP seat takes a set. The lever height MUST be set with the reg pressurized since it drops a fare amount when the reg pressurizes. The setup of a second stage is as much art as it is science. It's a balancing act between IP, spring pressure and lever height with some leeway for the parts settling in.
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Post by SeaRat on Apr 8, 2023 19:21:25 GMT -8
One thing a lot of people don’t realize is the screwing in and out the second stage nut will not influence the seat as the seat is in a round hole, and not a square hole like some other second stages. Therefore there is no danger of damaging the seat by this process, as it doesn’t turn much at all with the screwing in and out.
John
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DAAM IP
Aug 28, 2023 4:47:22 GMT -8
Post by snark3 on Aug 28, 2023 4:47:22 GMT -8
I'm not herman, but the second stage nut is used to set lever height. Adjusting the second stage body out reduces the spring pressure (lightening the cracking pressure). OK, I'm jumping in. Some of this has already been mentioned. The second stage body is not supposed to be screwed down tight, and one of the 3 holes must point down the intake horn. You want the second stage backed out as much as possible without leaking in order to achieve the least cracking effort. You may need to tighten it slightly if you get freeflow in the water.The small 5-40 nut on top of the second stage lever should be screwed down so the lever does not have any slop, but does not cause the poppet to leak. Lever height should be correct without slop. It might require bending, but usually not. Make sure the retaining ears do not get torqued when tightened. The lever should move very easily. You don't need to twist the ear tops or use thread lock on the ear screws. If the ears are twisted, carefully straighten them so they don't inhibit the lever movement. If the lever tips and/or diaphragm tabs show wear, clean them up with a file and/or fine emery cloth. Be sure your diaphragm is square to the tips when installing. Sometimes the lever will drop a bit when put on the tank and pressurized. Take up the slack while it's under pressure. Be sure to use a locknut, or use nail polish on the nut after adjustment. Also, glue your soft seat in the poppet. I have had the blue ones come out and get stuck in the volcano! Phil, Do I understand you correctly that the tabs that support the lever for the second stage do not need the tops twisted? Is that for adjustment or can they be left untwisted? Thanks
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DAAM IP
Aug 28, 2023 15:08:52 GMT -8
Post by vance on Aug 28, 2023 15:08:52 GMT -8
Yes you understand correctly. Do not twist the ears. If your ears are twisted, straighten them. This was an over-kill retaining policy that made things worse, rather than better. You want a very floppy lever.
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DAAM IP
Aug 28, 2023 15:35:18 GMT -8
Post by snark3 on Aug 28, 2023 15:35:18 GMT -8
Yes you understand correctly. Do not twist the ears. If your ears are twisted, straighten them. This was an over-kill retaining policy that made things worse, rather than better. You want a very floppy lever. Thanks Phil. I'm doing a RAM- among the last of them - and I bought new tabs.
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DAAM IP
Aug 28, 2023 17:20:18 GMT -8
Post by SeaRat on Aug 28, 2023 17:20:18 GMT -8
Okay, let me give some perspective on the twisting on the ears of the of the horseshoe "Support, Lock" (left and right). This is not mentioned in the U.S. Navy Diving Manual, March of 1970. However, it was a practice I saw during our instruction at the U.S. Naval School for Underwater Swimmers. Under normal conditions, the twisting does not need to be done. But the U.S. Navy divers did not alway work under normal conditions. They sometimes worked under combat conditions, and the equipment was potentially subjected to rather rigorous trauma (like explosions underwater) which could really rattly the regulator. To prevent the horseshoe from being dislodged under these conditions, the instructors recommended the twisting of the ears of this support after assembly. Because the diaphragm holds the horseshoe in position on the extreme end, and the nut holding seat on the other, there is little possibility of the horseshoe coming out from the ears of the Lock Support. But under combat conditions, all bets are off. So far as making things worse, if done correctly the twist doesn't affect the movement of the horseshoe; but not all people did it correctly.
John
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Post by luis on Aug 29, 2023 12:37:59 GMT -8
Okay, let me give some perspective on the twisting on the ears of the of the horseshoe "Support, Lock" (left and right). This is not mentioned in the U.S. Navy Diving Manual, March of 1970. However, it was a practice I saw during our instruction at the U.S. Naval School for Underwater Swimmers. Under normal conditions, the twisting does not need to be done. But the U.S. Navy divers did not alway work under normal conditions. They sometimes worked under combat conditions, and the equipment was potentially subjected to rather rigorous trauma (like explosions underwater) which could really rattly the regulator. To prevent the horseshoe from being dislodged under these conditions, the instructors recommended the twisting of the ears of this support after assembly. Because the diaphragm holds the horseshoe in position on the extreme end, and the nut holding seat on the other, there is little possibility of the horseshoe coming out from the ears of the Lock Support. But under combat conditions, all bets are off. So far as making things worse, if done correctly the twist doesn't affect the movement of the horseshoe; but not all people did it correctly. John Hi John, I am not sure I am following this concept. I am sure that you are aware that any underwater explosion capable of rattling a regulator that much, will more than certainly kill the diver. There are lots of information about the effects of underwater explosion on the human body, without needing to dig deep (no pun intended) ... This is not classified information... science.howstuffworks.com/explosion-land-water1.htmSo, what was the idea? that under combat condition, if they recover the body, another diver could use that same regulator without first servicing it? Maybe the instructor was being way too optimistic...
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