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Post by Jim Perdway on Sept 18, 2021 6:38:45 GMT -8
Overall this reg is in nice condition and I've done a few really shallow dives near my dock with it. I'd like to make sure it's tuned properly and truly dive-ready. This will be relatively new territory for me, but it seems that there is a lot of information available and parts for servicing these if needed. I've read that the first stage is identical to the conshelf, but I don't have experience with those either. I figured my first step should be the forum to help me get on the right track. The primary problem right now is a very slight leak. When I push the lever down and release, it will naturally seal up completely for 2 seconds, and then the flow starts. It happens pretty consistently this way, regardless of how much I press lever down
Any recommendations on how to proceed and good resources to use in addition to the service manual are much appreciated
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Post by james1979 on Sept 18, 2021 7:10:06 GMT -8
That description makes me suspect you have IP creep. That would suggest rebuilding the first stage (most likely seat or balance chamber O-ring causing the creep). If you have a hookah port adapter, you can use an LPI hose and IP gauge to check. If you can't find one, I can loan you one, or you can do what I've done on some.... liberal use of teflon tape with a splitter block (https://www.divegearexpress.com/dgx-lp-y-block-2-port-3-8-inch-f-1-port-9-16-inch-f) on the hookah port (it can be a bear to get sealed well, but will let you run an octo and LPI.
I would start with checking IP for creep, and if I'm right about that, rebuild the nozzle (1st stage).
Respectfully,
James
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Post by Jim Perdway on Sept 18, 2021 7:31:51 GMT -8
Thanks James, that’s kind of what I was suspecting without really even understanding what IP creep even is, I’ve just heard about it being a thing lol
I’ll get an adapter if there are any out there. How do I even access that hookah port? I’m guessing I take off the cap by unscrewing the 11/16 hex part (#17 in manual). It seems like it’s on there really good so I want to confirm before F-ing anything up
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Post by james1979 on Sept 18, 2021 7:58:41 GMT -8
Yep, item 17 is the hookah port cap. The port is actually an oxygen fitting, oddly enough.
IP creep is when the HP section isn't fully locking up, so on an IP gauge you'll see a fast recovery to approximately the IP set point, the a slower continuous increase (leading to the second stage being driven open).
I'm not an expert, but feel free to call if you need anything.
Best,
James
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Post by herman on Sept 18, 2021 8:54:32 GMT -8
I agree, classic description of IP creep. It will (likely) be one of 2 things, a defective HP seat and/or a bad balance chamber oring. Both parts are easy to get (used in darn near all USD/AL regs to this day). If you intend to dive the reg, it needs to be rebuilt anyway, including all the old rubber parts. First thing is to make sure you have a RAM, can't tell from this side, they look very close to a DAAM but use different parts.
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Post by SeaRat on Sept 18, 2021 8:59:32 GMT -8
Jimperedway, You need to go over to VintageDoublehose and download the Aqua-Lung Repair Manual.pdf. It is the one which is 31.6 MB in size. You can sign in here: personal.filesanywhere.com/fs/v.aspx?v=8d6d638a5f6075b5a46aOnce in (you have to sign in saying you agree to their terms), click the "Show All" button, scroll down until you find: "US Divers manuals,testing, parts drawings, all years covered" Click on it and download it. The RAM is on page 22. It has detailed instructions for the rebuild. The Royal Aquamaster has O-rings in the balance chamber and some may be leaking. If it holds for a few seconds, it probably isn't the seat itself. John |
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Post by luis on Sept 18, 2021 10:28:07 GMT -8
Based on what I read, maybe there is a need for some basic definition and information. I hope this is not too basic, but I will try to keep it simple. IP is Intermediate Pressure. It is the pressure delivered by the “pressure reducing” first stage. The job of the first stage is to reduce any tank pressure to a relatively constant Intermediate Pressure. The IP can vary, but the more consistent the easier it is for the second stage “demand valve” to operate and deliver a consistent performance. The term “balanced first stage” describes a pressure reducing first stage that the pneumatic forces are balanced and not affected by the changing tank pressure: resulting in a consistent “Intermediate Pressure” output, not affected by the changing tank pressure. A not-balanced first stage can have an IP change of 20 psi or more from a full to a close to empty cylinder. IP values typically range from about 110 psi to about 145 psi, but this is just rough typical numbers. From that view it is not possible to tell if that is a DA Aqua Master (non-balanced first stage) or a Royal Aqua Master (balanced first stage). If you show a side view, I can tell you what it is. I have to disagree with Herman on this one.  The first stage body of a Royal Aqua Master is about 1/8” longer than the DAAM. The easiest way to tell the difference is by the gap between the yoke and the main body.
The DAAM has very little gap (almost none) and with the yoke loose it barely moves up and down. The RAM will have a visible 1/8” gap between the yoke and the main body and the yoke will easily move up and down when it is loose. The internal first stage parts in these regulators are very different and they cannot be interchanged. So the first step is to determine what you have. With a side picture is not hard to tell. OK, I just talked to Herman. He meant from this view you can't tell what it is, which we can all agree. We would normally refer to this as the front view not the side... that was my miss-understanding of what he wrote.  |
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Post by herman on Sept 18, 2021 11:30:18 GMT -8
Luis just doesn't speak Southern, I had to translate for him. |
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Post by Jim Perdway on Sept 18, 2021 11:54:19 GMT -8
Thanks guys! I’m out of town for the weekend but I will check when I get home to confirm. When loosened, I remember the yoke moving as Luis described. I’m sure hoping someone didn’t just put a RAM cover on it  |
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Post by luis on Sept 18, 2021 12:04:04 GMT -8
If the cover said RAM that is a good indicator. But it is not always a guaranty. It does look like the parts are original (not a Frankenstein regulator). The loose yoke due to the longer first stage body is a definite indicator that it is a RAM and not a DAAM. Added: Yes, looking closer, I can see that the tabs on the second stage lever pivot have the factory twist (bend) and the threads on the second stage seat poppet has the factory thread spike. That regulator looks like it has never been serviced. Even back in the 70's, when we serviced one of these regulators, we quit doing that metal deformation. It had no advantage, even when we had "unlimited" replacement parts, there is no need and it damage the parts. So, since it has not been serviced, the original High Pressure (HP) seat would be made out of hard black rubber that tended to be somewhat reliable (not always) for a while, but eventually it would allow a small leak or IP creep. The new blue seats from Aqua Lung (and some of the after market ones) are much better. Actually, Aqua Lung new blue seats are just amazingly reliable. |
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Post by SeaRat on Sept 18, 2021 12:58:31 GMT -8
If the cover said RAM that is a good indicator. But it is not always a guaranty. It does look like the parts are original (not a Frankenstein regulator). The loose yoke due to the longer first stage body is a definite indicator that it is a RAM and not a DAAM. Added: Yes, looking closer, I can see that the tabs on the second stage lever pivot have the factory twist (bend) and the threads on the second stage seat poppet has the factory thread spike. That regulator looks like it has never been serviced. Even back in the 70's, when we serviced one of these regulators, we quit doing that metal deformation. It had no advantage, even when we had "unlimited" replacement parts, there is no need and it damage the parts.So, since it has not been serviced, the original High Pressure (HP) seat would be made out of hard black rubber that tended to be somewhat reliable (not always) for a while, but eventually it would allow a small leak or IP creep. The new blue seats from Aqua Lung (and some of the after market ones) are much better. Actually, Aqua Lung new blue seats are just amazingly reliable. I think from the U.S. Navy point of view, that metal deformation was put in there because some Navy divers jumped off a high deck or out of a helicopter into the water, and there was quite a lot of force applied by the subsequent splash onto the diaphragm. They wanted to ensure that the main lever did not leave that pivot, as the Aquamaster/RAM would then become non-functional. John |
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Post by Jim Perdway on Sept 18, 2021 14:05:41 GMT -8
Thank you for the insight, Luis. Seeing how caked on and destroyed the duckbill was, it seemed that the cover wasn’t even off in years. I don’t quite follow the factory bend concept being an indicator of service history. Did it come from factory this way, and you guys would eventually come to straighten them upon servicing?
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Post by luis on Sept 18, 2021 14:06:42 GMT -8
If the cover said RAM that is a good indicator. But it is not always a guaranty. It does look like the parts are original (not a Frankenstein regulator). The loose yoke due to the longer first stage body is a definite indicator that it is a RAM and not a DAAM. Added: Yes, looking closer, I can see that the tabs on the second stage lever pivot have the factory twist (bend) and the threads on the second stage seat poppet has the factory thread spike. That regulator looks like it has never been serviced. Even back in the 70's, when we serviced one of these regulators, we quit doing that metal deformation. It had no advantage, even when we had "unlimited" replacement parts, there is no need and it damage the parts.So, since it has not been serviced, the original High Pressure (HP) seat would be made out of hard black rubber that tended to be somewhat reliable (not always) for a while, but eventually it would allow a small leak or IP creep. The new blue seats from Aqua Lung (and some of the after market ones) are much better. Actually, Aqua Lung new blue seats are just amazingly reliable. I think from the U.S. Navy point of view, that metal deformation was put in there because some Navy divers jumped off a high deck or out of a helicopter into the water, and there was quite a lot of force applied by the subsequent splash onto the diaphragm. They wanted to ensure that the main lever did not leave that pivot, as the Aquamaster/RAM would then become non-functional. John Someone might have thought that, but that lever can't really jump off. Try it and you will see what I am talking about. The seat poppet will not let it pop-off. You actually have to deform something to make that happen. With the amount of force to lift a lever... the least of your concerns is the regulator... you already kill the diver. I know young sailors used to think they are bullet-proof, but they are not. It is interesting. I am not officially an HSI (Human System Integration) engineer, but I have had to play the part many time. One of the areas I deal a lot with is fall protection... or better described as fall arrest. There is a lot of interesting data (ASTM, OSHA, etc) about the maximum force that a human can survive even with a well fitted fall arrest harness. Warning: As a previous EMT and wilderness rescue I may have a sense of humor that may be a bit macabre. So, I always say that the design of some fall arrest anchors is not just to avoid the human from splatting on the deck, but also to contain the body to return it to the family. The point is that some fall protection anchors far exceed the possible survival of the human it is intended to protect. The anchors are not intended to absorb or attenuate energy, the rigging is supposed to do that.
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Post by herman on Sept 18, 2021 14:07:39 GMT -8
If the brass nut does not come off easily, don't put any pressure one it. The seat holder is brass and will break. Instead, remove the entire LP assembly, hold the LP seat with pliers and turn the nut IN slightly, rocking it back and forth until you loosen the staking. If you do break it, all is not lost, reproductions exist.
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Post by luis on Sept 18, 2021 14:24:07 GMT -8
Thank you for the insight, Luis. Seeing how caked on and destroyed the duckbill was, it seemed that the cover wasn’t even off in years. I don’t quite follow the factory bend concept being an indicator of service history. Did it come from factory this way, and you guys would eventually come to straighten them upon servicing? Correct. We always straighten the two tabs. Bending them for security was an extreme over kill and most important is that the bend could cause some binding and extra friction on the lever motion. Instead of staking the nut we used a dab of nail polish to keep it from backing out. Silicone would work, Locktite would a bit of an overkill making harder to service the next time... |
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