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Post by antique diver on Sept 9, 2023 10:50:38 GMT -8
If you can, push the IP as high as 135. Please let me know how it's going so I can consult with you. Just a reminder about the IP. The 135 figure has pretty much stuck in most peoples mind, and has become the "norm". It's true that 135 psi works well with most regs. I tend to use that as a starting pressure too, but vary it as needed. Other factors, such as lever height, second stage spring tension, venturi changes, etc., can be adjusted to cause that 135 IP to work to satisfaction.... but that's not the real limit of the design. The Dacor, Mares, US Divers and some other diaphragm first stages are all built on the same basic design of the first Aqualungs. With that in mind there is a service bulletin from USD/Aqualung, dated August 28, 1985 that should be of interest to all who tinker with these regulators. The notice states "The recommended acceptable intermediate pressure for diaphragm-operated first-stage regulator is 130 to 160 psig." Then, on the next page they back off a little when they concede IP directly affects the flow characteristics of the regulator "at depth (in excess of 100 ft.)" Then they temper the psi range a little, saying "USD has established an optimum window for the intermediate pressure of its factory made and adjusted regulators to be 140 +/- 5 psig. This [IP range] gives optimum regulator performance for the standard sport diving environment."So that's a little confusing as they dance around the IP numbers, but it does point out that the regs will be ok at up to 160 if necessary to meet performance needs (but not below 100' ??). I have only used 160 IP when using a Poseidon Cyklon second stage. Here's a list of the regulators to which they specifically refer. By reg part number: 1047, 1048, 1014, 1015, 1019, 1020, 1016,1017,1035,1036,1081,1088,1011,1012,1028,1029 |
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Post by SeaRat on Sept 9, 2023 11:40:03 GMT -8
If you can, push the IP as high as 135. Please let me know how it's going so I can consult with you. Just a reminder about the IP. The 135 figure has pretty much stuck in most peoples mind, and has become the "norm". It's true that 135 psi works well with most regs. I tend to use that as a starting pressure too, but vary it as needed. Other factors, such as lever height, second stage spring tension, venturi changes, etc., can be adjusted to cause that 135 IP to work to satisfaction.... but that's not the real limit of the design. The Dacor, Mares, US Divers and some other diaphragm first stages are all built on the same basic design of the first Aqualungs. With that in mind there is a service bulletin from USD/Aqualung, dated August 28, 1985 that should be of interest to all who tinker with these regulators. The notice states "The recommended acceptable intermediate pressure for diaphragm-operated first-stage regulator is 130 to 160 psig." Then, on the next page they back off a little when they concede IP directly affects the flow characteristics of the regulator "at depth (in excess of 100 ft.)" Then they temper the psi range a little, saying "USD has established an optimum window for the intermediate pressure of its factory made and adjusted regulators to be 140 +/- 5 psig. This [IP range] gives optimum regulator performance for the standard sport diving environment."So that's a little confusing as they dance around the IP numbers, but it does point out that the regs will be ok at up to 160 if necessary to meet performance needs (but not below 100' ??). I have only used 160 IP when using a Poseidon Cyklon second stage. Here's a list of the regulators to which they specifically refer. By reg part number: 1047, 1048, 1014, 1015, 1019, 1020, 1016,1017,1035,1036,1081,1088,1011,1012,1028,1029 This is interesting to me, as I just pulled out my Aqua-Lung Repair Manual, June 1, 1971 edition, and for the "Aqua-Master Regulator No. 1010.00" it states "NOTE: The intermediate pressure of this regulator is to be set at 110 pounds per square inch (psi)." I believe that is for a full tank at 3000 psi tank pressure. Now, if so, it would equate to about 130-140 psi at 500 psi, as this is an unbalance diaphragm regulator. But when I go to the last section, about the "Royal Aqua Master" No. 1046.00" it states "...Screw test gauge (Ref 1116-00, TOOLS) with adapter (Ref 1125-00, TOOLS) into 2nd stage seat of body (18). Open bleeder valve of test gauge. Raise air supply to 2000 pounds per squared inch (psi). After flow begins, slowly close bleeder valve on test gauge off. Adjust adjustment screw (28) until test gauge indicates approximately 100 psi. Bleed air and repeat check two or three times to check stability of setting..." It doesn't go back and say to re-adjust the IP up to 130-140 psi, whcih is critical as this regulator is balanced, and the IP won't change with tank pressure. So it appears that Aqualung actually de-tuned this regulator so as to make it breath harder, at least in this publication! I just checked with Basic Scuba, Fred Roberts, and he mentions in trouble shooting the DA Aquamaster that the IP is set to 110 psi too, but doesn't mention whether that's on a full or 500 psig tank. My way of tuning these regulators is to turn on the air, adjust them until they leak (at 500 psi tank pressure for the DA Aquamaster), and back it off 1/4 turn. For the DA Aquamaster at 500 psi tank pressure, that's about 140+ psi (sometimes up to 160 psi). John |
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Post by nikeajax on Sept 9, 2023 13:14:21 GMT -8
It's always been my finding that, yes, you can go a lot higher, but it will cut down on your economy, ie, your time underwater. Also, the higher the IP, the more likely you are to experience discomfort from too much air rushing in all at once  Just a thought  JB |
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Post by antique diver on Sept 9, 2023 14:36:03 GMT -8
It's always been my finding that, yes, you can go a lot higher, but it will cut down on your economy, ie, your time underwater. Also, the higher the IP, the more likely you are to experience discomfort from too much air rushing in all at once Just a thought JB I'm not suggesting that all regulators be subjected to 160 psi IP. But, that may be applicable to a reg that just won't breathe well at 135 IP, and all other tuning tricks have been tried. My Poseidon Cyklon's behave quite well at 160 (and I think that's similar to what the specs call for), but my MR12's or TKR-hotrod Trieste would probably try to inflate me on a heavy breath.  |
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Post by antique diver on Sept 9, 2023 14:44:13 GMT -8
John, Thanks for the input, and reminder in the last part about the simplest way to tune the IP. Lots of us do it that way.
Keep in mind that the bulletin on IP numbers was issued in 1985,
and I am pretty darn certain that all the diaphragm USD/Aqualung first stages were balanced well before then, so there's not much variation in IP over the range of input psi's. We aren't talking about the DAAM and its predecessors, and that may be a whole different story.
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Post by nikeajax on Sept 9, 2023 16:20:02 GMT -8
Bill, I totally agree with you my friend! I thought I would add my comment just in case someone doesn't understand the implications of doing so: I should have stated that in the first place--sorry! Sleep deprivation does bad things to the brain  Kinda turns you into a zombie...  JB |
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Post by SeaRat on Sept 9, 2023 17:14:16 GMT -8
John, Thanks for the input, and reminder in the last part about the simplest way to tune the IP. Lots of us do it that way. Keep in mind that the bulletin on IP numbers was issued in 1985, and I am pretty darn certain that all the diaphragm USD/Aqualung first stages were balanced well before then, so there's not much variation in IP over the range of input psi's. We aren't talking about the DAAM and its predecessors, and that may be a whole different story. That's why I put in the part number for the DA Aquamaster, as it was before the part numbers you listed. Also, the Royal Aquamaster was one number before your stated numbers. John |
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Post by vance on Sept 10, 2023 16:07:58 GMT -8
This discussion has been moved to a new thread. We are the most goin' off-topic group ever! Not a bad thing, since it produces discussion. But, someone (one of us moderators) has to wrangle it all to make it searchable.
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