Thank you for the simple and clear explanations of the dos and don'ts of setting the IP on one's regulator first stage. These tech tips are some of the best scuba tube content.
This is such good stuff to understand. I feel much more comfortable knowing how and why something is done. I really enjoy learning these things. I may not want to service my equipment, but I do like knowing how the pro's do it. Thanks.
G'day Alex,just want to thankyou for this video-i had a leaking secondary oceanic but,after watching your video,fixed the problem myself much to the disgust of greedy technicians here in Sabang on Mindoro,the Philippines. Again,many thanks mate.
Mr. Peirce, my utmost respect to you Sir. Your videos are invaluable and always with something to learn. Can you please point me to the parts of this IP measurement tool on this video (with the lever)? Although I like to support my LDS I also enjoy knowing how to do my own basic maintenance and, with your instructional videos makes it even more enjoyable. Thanks for sharing your knowledge, Salud!
I'm trying to adjust IP, i have a SEAC 1st stage, the pressure is in 12 bar, but i cannot reach 10 bars ... The 2nd stage id free flowing, i should adjust first 2nd stage for stop free flowing and then adjust IP, and then finally again 2nd stage?
Nice information on IP adjustment on common first stages. Ever thought about showing IP adjustment on environmentally sealed 1st stages, like Apeks FSR/FST? Keep up the good work.
Sure. It's exactly the same process except you have to get past that cap first. I think we just did a video on that. It should be out soon. The adjustment process is identical. Alec.
Late to the party, but i'd like to add one important caveat: some 1st stages have an adjuster that changes the height of the high pressure valve seat, rather than the preload of the IP spring. Even though these have an externally accessable adjustment point, they must NOT be adjusted when their is primary pressure applied to the stage, ie when the cylinder is turned on! This is because adjustment under pressure means the HP seat is in contact with the HP orrifice, and that turning force can cut the soft seat material! To adjust these, your check the pressure, turn off the cylinder valve, bleed the pressure down, turn the adjuster slightly, then turn the cyl valve back on and reject, repeating as necessary till the IP is within spec. Case in point here is the very popular Scubapro Mk25 piston 1st stage. So in all cases, checl the service manual before you twiddle stuff!!!! ;-)
Your comments are correct but for many divers, everything past your second sentence lost them. My intent was to give divers an understanding of the general process, not to argue individual brand differences. You sound like an experienced service pro so thanks for the feedback. Alec
@@AlecPeirceScuba_SeaHunter Absolutely with you on that one Alec! It's good to give everyone an idea of how things work, whatever their skill or knowledge level, but i just wanted to add in that there are some circumstances (actually quite rare tbh) where twiddling things can damage your kit if you don't follow certain procedures! BTW i'm not a scuba tech pro, but i do design and develop Formula 1 cars for a living, so "twiddling things" is certainly in my blood lol! Keep up the good work on your great channel :-)
Hey, my wife says I can talk about anything! That's actually not true but I do have a reputation for being an expert on many things and also for being successful in many areas. Let me tell you my secret. Shhhh. 1. I only address subjects with which I'm very familiar. 2. I only try things which I'm pretty sure I can do with success. That doesn't mean I don't try new stuff nor that I have never failed but I've become successful at analyzing things using these 2 rules. Now everybody thinks I know everything and can do anything. Shhh. I have used a pony system many times. In fact, I started using a type of pony system before it was called pony or even a redundant air system. We didn't use those fancy terms in the 60's/70's. We just called it extra air! I have a picture of myself with a beautiful pony system that I made in the early 70's. It's a steel 72 tank with a smaller pony tank beside it, all chrome plated! It gleams in the sun! I made a custom backpack with a long chrome plated band to hold both tanks and used it with a chrome 2 hose regulator on the main tank and a chrome single hose on the pony. Chrome plating was the big thing in the 70's. Anyway, to your question, assuming you're using a regular full sized tank as the main source, I usually suggest the 19 cubic foot pony as the best choice. It's not too big to carry around or to cause attitude problems (the larger 30 or 40 cf tanks tend to flop over) but it has enough to air to actually be useful. Even at 100' a 19cf will last for 5 minutes which should be enough for you to figure out what to do next. At 30' it will give 10-12 minutes of air - good for checking props or recovering dropped things. So it's the most useful size. A simple regulator, no SPG, BCD inflator or Safe Second needed, on a 19cf tank clamped to the side of your main tanks is the simplest, easiest to deploy and most affordable set-up I can suggest. XS Scuba has a system called 'XTR Extra Air - Complete Backup Rescue System' that is as close to perfect as I've seen for less than $500 - tank, reg, mini gauge and pony mount too. It even comes with a DIN valve for you DIN lovers and a flex hose. Hope that helps. Alec
Oh wow.. thank you so much for the reply, I really did not expect such a detailed answer. Since I live in Europe I was thinking of a 3ltr tank and carry it as a stage strap. Let's hope I will never need it but nevertheless better safe than sorry. Anyway, great answer and thank you for taking the time to reply. Keep up the good work..
Interesting video. I just got a cheap IP gauge. I found it interesting my wife’s Aqualung Minton reg was running 10psi higher than mine. Mine was 135. We’ve only got a half a dozen dives in them. I was surprised they’d come out of production with that much difference.
Most IP's have a +/- variance of 5 to 7 psi from the service manuals. It's not a big difference as long as the 2nd stage is tuned properly. Keep on diving.
Hi Alec, I have been a big fan of your series for a while now, not only as a diver, an instructor but also as an ASSET certified Dive Industry Technician. I have recently open a dive center in Indonesia and opted for Apeks regulators. I have access to splitted view and technician manuals and also can rely on my experience with other regulator brands to perform decent overall/service of these but I feel like I would (like the rest of your followers) benefit from your extended experience servicing first and second stages, and particularly Apeks ones. Would you be ready to make a video describing best practices for these ? It would be greatly appreciated ;)
Apeks should supply you with all the service information you need, including videos, so that you can properly disassemble and reassemble and tune their regulators. All manufacturers do this. I'd love to help but for me to make a video showing the service process for a specific brand is not going to happen. Alec
Alec pierce scuba love the vids and everything been diving a year absolutely fell in love with it . Have you ever or will you do a tech tips video on the pros and cons of full face mask vs traditional mask. And I'd like yo know your thoughts on logging dives or if you even log them had 3 structors 1 told us absolutely and the other two said ehhhh you can but no harm no foul if you dont
I'm looking into a vid on full face. We'll see. I have a dozen or more full log books. With 5000+ dives I really have no more need to log but it sure is fun looking back at my dives from the 60's and 70's. The gear, the old dive sites, my buddies (many gone now) and the stuff we did is a hoot to recall. I like to see divers log their dives until they have several hundred at least. After that there's no practical benefit but sometimes you want to check on a dive site from years before - maybe it's location, condition, entry point, stuff like that. Hard to do without a detailed log. Realize that you need prove of 100 dives to become and instructor. A log book is the best and fastest proof. After Open Water & Advanced it's a personal choice but I vote yes! Alec
Great video!! THANK YOU so much for the information! Learning new things every time in your videos. This seems really complicated tho, rather take it to the dive store haha. but useful information as always!
If you are really mechanically inclined, most simple reg repairs are fairly easy. But, only a professional, trained service person can do a complete and safe overhaul of your reg. Take care. Alec
Excellent!!! My Goodness, I am learning a lot with you!!! God blessed you!! We would like to see Kevin, I am curious 😀. Hi Kevin!!! I am your fan too!! Greetings from Caribbean, Puerto Rico!!! Do you have a video or recomend a video that help me intruduce to the side mount driving? Which are the advantage and disadvantages? Or video that help me understand and learn about tecnical diving!!! Thnks!!!
Thanks for watching Ramon. I'll have to do a video on sidemount I guess. It's a very small portion of divers but there are lots of questions. I don't know of any videos. The most common source of info on sidemount or tech diving is the internet or an instructor. Take care. Alec
Alec as you mentioned when the first stage fails the reg will free flow. Now what will happen if a BCD Lp inflator fails? Will it fill the BCD with air or will it totally cut off your air to your BCD? Thanks in advance for the info and another great video
BCDs are remarkably reliable but there are 2 areas of concern. 1. The PIV (Power Inflator Valve on the end of the BCD big hose) will deteriorate over time if not fastidiously care for. If it fails it usually either leaks air to the water or leaks air into the BCD. In some cases it fails to provide air at all. None of these situations is good but, having become dependent on the ability of the BCD to maintain our buoyancy, divers faced with a BCD that slowly fills throughout the dive find it annoying at best and potentially dangerous at worst. While a BCD that won't fill sounds bad, assuming the diver is properly weighted, it's not usually life-threatening. These valves should be serviced as often as your regulator. If it is not cleaned regularly it can become so badly corroded that the only solution is replacement of the valve (not the BCD - just the valve for less than $100). 2. The LP hose can also be a source of problems although less often. Inside the end of the hose is a Schrader valve just like the one in a bicycle tire valve. These will also corrode if not rinsed and few people do that consciously. It's usually done while rinsing the regulator itself although if you're in the habit of rinsing your reg under a tap or hose rather than giving it a good soak, this valve doesn't get touched. If that little $0.10 valve fails you get no air. It should be replaced at every regulator service (less than $10). Also in the same spot, there is a small O-ring that seals the spigot on the BCD main hose into the LP inflator hose so the air won't leak out. I have never seen a dive store that regularly replaces that O-ring although it is even more subject to sun, heat and salt that the tank valve O-ring. The reason is simply that It's a real nuisance to replace. If not practiced at replacing it, service staff can find it frustratingly difficult to get to and to insert a new one. Insist that it be done with the Schrader valve change. Good question. This might be a good Tech Tip topic. Thanks. Alec
Hi Steve, Watch this video on how to service the LPI schrader valve, S06E05 Servicing Your Inflator Hose, th-cam.com/video/yaXyn4-cxKs/w-d-xo.html Thanks for the suggestion. I will add it to our ideas list.
One more question...how would you do the adjustment on a environmentally sealed 1st stage reg? As per one of your videos, I understand that the adjustment bolt would be under the rubber boot that is filled with liquid.
In this case you'd need to check the service manual where it will explain how to do this adjustment. That's assuming the manufacturer allows service manuals to be given or sold to customers... some do some don't.
Hi Alec, I'm having difficulty understanding regulators. Is the IP always Ambient + 150psi (approximately)? So in the shop the IP is 150psi, ambient is 0psi gauge pressure; At 30 meters/99ft, ambient is 3x15psi = 45psi; IP would auto adjust to 150psi + 45psi = 195psi? How can we safely breathe air that's 150psi higher than our surroundings? How does this affect our BCDs and drysuits? Presumably it must be something to do with the low flow rate? Really great videos by the way, I'm new to your channel and I'm a big fan! You have a great manner on camera, very engaging and knowledgeable. Thank you!
yes, IP is ~150psi+AP, that's why it has openings otherwise that wouldn't be necessary How can we safely breathe air that's 150psi higher than our surroundings? - 2nd stage reduces it to IP ambient. Diaphragm is "preloaded"with AP and then you create under-pressure by breathing in, which gets equalized by the lever opening and letting in air from IP pressured hose, because the diaphragm presses on that lever (Alec also has a video explaining that, prbly better) How can we safely breathe air that's 150psi higher than our surroundings? - higher IP would mean faster inflation, but you shouldn't have to full press the button anyway hope that clarified it, otherwise have a look here: www.thoughtco.com/how-does-a-regulator-work-2963185
Yep! IP is ambient +150 (or whatever the factory setting for IP at surface is supposed to be - 125psi to 160psi). You've answered your own question. The IP is balanced at ambient. That is, no air comes out of the reg at any pressure or any depth until you inhale. Then the air that comes out is the correct pressure to fill your lungs as you inhale. When you stop inhaling (lungs full?), the air flow stops. Your lungs will only accept air until the pressure inside equals the pressure outside. They will not overinflate - unless you block the windpipe somehow. If the air pressure was equal to ambient i.e. not 150psi above ambient, you would not be able to inhale. Your lungs have virtually no ability to suck air as you can prove by trying to breathe through a long tube (say, 4' long) while sitting on the bottom of the pool. Hopefully, this is clear. Thanks for your question. Alec
Yokes are pretty much universal in design and fit. However, how they attach to the regulator varies between manufacturers. Most attach by means of a yoke nut. The yoke slips over a threaded stem and a nut threads onto that stem to secure the yoke in place. Other combine the nut and the threaded stem into a single bolt that fits into the yoke and then tightens into the reg body. Another less common arrangement has a long threaded stem onto which the yoke, also threaded, screws. The yoke is not tightened down in this case but is held from unscrewing by a large C-Clip. I suspect this is the one you are looking at since in this style the threads are quite visible. I'm guessing it's a US Divers regulator. They used that system for a long time. Thanks for watching. Alec
Thanks Alec. Question: I feel that my newly bought overbalanced diaphragm regs release too much air. I run out a lot quicker than I used to with basic rental piston regs. Will it help if I reduce the ip on the first stage? My second stage comes with an flow adjustment lever and even at the lowest mark I feel theres still too much air flow with every breath.
There could be many factors affecting your air consumption, not just the regulators. As for reducing the IP, don't. The manufacturer set the IP range to be ideal for diving, changing it yourself without knowing the effects is not safe. Look for my video on setting breathing resistance # S08E01 as breathing effort is set at the 2nd stage, not the IP. Take your regs to your local dive store and discuss your concerns with them and have the adjust the 2nd stage breathing while your there for you to check until you find a setting you like. Thanks for watching. Alec
So what if you are mixing and matching first and second stages with different factory recommended IPs? Do you set the first stage to the factory IP and adjust the second accordingly, or do you set the first to match the factory IP for the second stage so it breathes well?
Always set the 1st stage as dictated by the manufacturer. It is determined by very specific requirements. Then simply adjust the 2nd stage to suit your breathing needs, light enough to provide air easily but not enough to create free flow. There is no "setting" for the 2nd stage, It is adjusted to the IP coming from the first. Alec
Hi Alec, I have a question for you: Now that I am an OWD thanks to your advice I got my mask and snorkel, but I am seriously considering buying a pair of fins, more precisely a pair of split fins, but I have 2 doubts the first one is the size of the foot pocket ( I am size 9.5 US) so do I need to buy it in a regular size or in a large size, the other doubt is about which fin is better I am deciding between the Scubapro twin jet, the mares raptor, and the oceanic vortex and the TUSA SF15 expert I saw some of your videos with some of that fins, so I want to know the quality of them, and what fin do you prefer. Thank you ( I had a good pair of aqualung splash jr split fins and I loved them but now they dont fit me, I also tested other normal fins but I still prefer the split ones) This time I dont care about the price once again thank you.
Hi Piolo! Awesome that you got your OWD now! I would buy a Large size when you have 9.5 us size, especially when you want to wear shoes with big soles. You also can look for at the Atomic split fins: www.atomicaquatics.com/splitfins.html
Hallo Alce , I have tow Scubapro First Stage MK20, the intermediate pressure is different between them , one of them is 9,6 bar and the other one is 10,4 bar , is that normal?
I found a good answer on www.scubaboard.com. I know a lot but unlike my wife who knows everything, I also have to do research. This is a great resource to ask questions to the global scuba community. DA Aquamaster posted this answer: It is a Mk 20 specific problem. The Mk 20 had three different piston designs depending on when it was made. 1. The early piston was a stainless steel piston with a knife edge seating surface. It worked great. 2. The mid production Mk 20 used a brass tipped piston that had a rounded seating edge. They were notorious for having a mushy lockup and IP creep and in fact have a much looser set of allowable specifications for IP creep. A "normal" piston is expected to lock up very solidly with little or no creep in the first 5 seconds and none after that. The Mk 20 was allowed about 5 psi of creep initially and a few more psi over the next minute. I pretty much replace them on site as it is a "when they fail" rather than "if they fail" issue. 3. The late production Mk 20 used the same composite piston used in the current Mk 25. It also has a knife edge and locks up very solidly. It is a direct replacement part and the dealer cost is about $25. I it also replaced free under warranty if the IP will not lock up. If you do not have a brass tipped piston, I suspect the seating surface is damaged so piston replacement is still the most likely fix. NOTE: read the full postings here: www.scubaboard.com/community/threads/scubapro-mk-20-pressure-creep.245312/
Does it play a tune you know? But seriously, a high pitched whistle while inhaling is a sign the 1st stage needs service as the o-ring around the piston is likely wearing. As tank pressure drops the noise drops due to the pressure on the piston reducing and the speed it moves up/down is slower. It's still usable but your buddy may get annoyed. Thanks Mike.
Thank you for the simple and clear explanations of the dos and don'ts of setting the IP on one's regulator first stage. These tech tips are some of the best scuba tube content.
Glad you enjoyed it!
A
You are the perfect teacher. Congratulations.
Thank you and thanks for watching.
Alec
Thanks once again Alec, I like these Tech Tips videos they are so informing, keep them coming..................................................
Thanks Bristol.
Alec
This is such good stuff to understand. I feel much more comfortable knowing how and why something is done. I really enjoy learning these things. I may not want to service my equipment, but I do like knowing how the pro's do it. Thanks.
I've always enjoyed knowing how something works and I'm guessing lots of others do too.
I'm glad you enjoyed it.
Alec
G'day Alex,just want to thankyou for this video-i had a leaking secondary oceanic but,after watching your video,fixed the problem myself much to the disgust of greedy technicians here in Sabang on Mindoro,the Philippines.
Again,many thanks mate.
Glad it helped
A
Mr. Peirce, my utmost respect to you Sir. Your videos are invaluable and always with something to learn. Can you please point me to the parts of this IP measurement tool on this video (with the lever)? Although I like to support my LDS I also enjoy knowing how to do my own basic maintenance and, with your instructional videos makes it even more enjoyable. Thanks for sharing your knowledge, Salud!
Amazing content, please dont stop
I won't. Lots more coming.
A
I'm trying to adjust IP, i have a SEAC 1st stage, the pressure is in 12 bar, but i cannot reach 10 bars ... The 2nd stage id free flowing, i should adjust first 2nd stage for stop free flowing and then adjust IP, and then finally again 2nd stage?
Nice information on IP adjustment on common first stages. Ever thought about showing IP adjustment on environmentally sealed 1st stages, like Apeks FSR/FST? Keep up the good work.
Sure. It's exactly the same process except you have to get past that cap first.
I think we just did a video on that. It should be out soon.
The adjustment process is identical.
Alec.
Late to the party, but i'd like to add one important caveat: some 1st stages have an adjuster that changes the height of the high pressure valve seat, rather than the preload of the IP spring. Even though these have an externally accessable adjustment point, they must NOT be adjusted when their is primary pressure applied to the stage, ie when the cylinder is turned on! This is because adjustment under pressure means the HP seat is in contact with the HP orrifice, and that turning force can cut the soft seat material! To adjust these, your check the pressure, turn off the cylinder valve, bleed the pressure down, turn the adjuster slightly, then turn the cyl valve back on and reject, repeating as necessary till the IP is within spec. Case in point here is the very popular Scubapro Mk25 piston 1st stage. So in all cases, checl the service manual before you twiddle stuff!!!! ;-)
Your comments are correct but for many divers, everything past your second sentence lost them. My intent was to give divers an understanding of the general process, not to argue individual brand differences. You sound like an experienced service pro so thanks for the feedback.
Alec
@@AlecPeirceScuba_SeaHunter Absolutely with you on that one Alec! It's good to give everyone an idea of how things work, whatever their skill or knowledge level, but i just wanted to add in that there are some circumstances (actually quite rare tbh) where twiddling things can damage your kit if you don't follow certain procedures! BTW i'm not a scuba tech pro, but i do design and develop Formula 1 cars for a living, so "twiddling things" is certainly in my blood lol! Keep up the good work on your great channel :-)
Hi Alec, great series. Love it. Can you talk about pony system tank sizes and possible adjustments?
Hey, my wife says I can talk about anything!
That's actually not true but I do have a reputation for being an expert on many things and also for being successful in many areas.
Let me tell you my secret. Shhhh.
1. I only address subjects with which I'm very familiar.
2. I only try things which I'm pretty sure I can do with success.
That doesn't mean I don't try new stuff nor that I have never failed but I've become successful at analyzing things using these 2 rules. Now everybody thinks I know everything and can do anything. Shhh.
I have used a pony system many times. In fact, I started using a type of pony system before it was called pony or even a redundant air system. We didn't use those fancy terms in the 60's/70's. We just called it extra air!
I have a picture of myself with a beautiful pony system that I made in the early 70's. It's a steel 72 tank with a smaller pony tank beside it, all chrome plated! It gleams in the sun! I made a custom backpack with a long chrome plated band to hold both tanks and used it with a chrome 2 hose regulator on the main tank and a chrome single hose on the pony. Chrome plating was the big thing in the 70's.
Anyway, to your question, assuming you're using a regular full sized tank as the main source, I usually suggest the 19 cubic foot pony as the best choice. It's not too big to carry around or to cause attitude problems (the larger 30 or 40 cf tanks tend to flop over) but it has enough to air to actually be useful. Even at 100' a 19cf will last for 5 minutes which should be enough for you to figure out what to do next. At 30' it will give 10-12 minutes of air - good for checking props or recovering dropped things. So it's the most useful size. A simple regulator, no SPG, BCD inflator or Safe Second needed, on a 19cf tank clamped to the side of your main tanks is the simplest, easiest to deploy and most affordable set-up I can suggest.
XS Scuba has a system called 'XTR Extra Air - Complete Backup Rescue System' that is as close to perfect as I've seen for less than $500 - tank, reg, mini gauge and pony mount too. It even comes with a DIN valve for you DIN lovers and a flex hose.
Hope that helps.
Alec
Oh wow.. thank you so much for the reply, I really did not expect such a detailed answer. Since I live in Europe I was thinking of a 3ltr tank and carry it as a stage strap. Let's hope I will never need it but nevertheless better safe than sorry. Anyway, great answer and thank you for taking the time to reply. Keep up the good work..
Brilliant advice as usual.
Thanks David.
Alec
Very interesting and absolutely correct.
Thanks Karl.
Alec
Interesting video. I just got a cheap IP gauge. I found it interesting my wife’s Aqualung Minton reg was running 10psi higher than mine. Mine was 135. We’ve only got a half a dozen dives in them. I was surprised they’d come out of production with that much difference.
Most IP's have a +/- variance of 5 to 7 psi from the service manuals. It's not a big difference as long as the 2nd stage is tuned properly. Keep on diving.
@@AlecPeirceScuba_SeaHunter thanks!
Hi Alec, I have been a big fan of your series for a while now, not only
as a diver, an instructor but also as an ASSET certified Dive Industry
Technician. I have recently open a dive center in Indonesia and opted
for Apeks regulators. I have access to splitted view and technician
manuals and also can rely on my experience with other regulator brands
to perform decent overall/service of these but I feel like I would (like
the rest of your followers) benefit from your extended experience
servicing first and second stages, and particularly Apeks ones. Would
you be ready to make a video describing best practices for these ? It
would be greatly appreciated ;)
Apeks should supply you with all the service information you need, including videos, so that you can properly disassemble and reassemble and tune their regulators. All manufacturers do this.
I'd love to help but for me to make a video showing the service process for a specific brand is not going to happen.
Alec
Thanks Alec.
You are welcome.
A
Alec pierce scuba love the vids and everything been diving a year absolutely fell in love with it . Have you ever or will you do a tech tips video on the pros and cons of full face mask vs traditional mask. And I'd like yo know your thoughts on logging dives or if you even log them had 3 structors 1 told us absolutely and the other two said ehhhh you can but no harm no foul if you dont
I'm looking into a vid on full face. We'll see.
I have a dozen or more full log books.
With 5000+ dives I really have no more need to log but it sure is fun looking back at my dives from the 60's and 70's. The gear, the old dive sites, my buddies (many gone now) and the stuff we did is a hoot to recall.
I like to see divers log their dives until they have several hundred at least.
After that there's no practical benefit but sometimes you want to check on a dive site from years before - maybe it's location, condition, entry point, stuff like that. Hard to do without a detailed log.
Realize that you need prove of 100 dives to become and instructor. A log book is the best and fastest proof.
After Open Water & Advanced it's a personal choice but I vote yes!
Alec
Great video!!
THANK YOU so much for the information! Learning new things every time in your videos. This seems really complicated tho, rather take it to the dive store haha. but useful information as always!
If you are really mechanically inclined, most simple reg repairs are fairly easy. But, only a professional, trained service person can do a complete and safe overhaul of your reg.
Take care.
Alec
Excellent!!! My Goodness, I am learning a lot with you!!! God blessed you!! We would like to see Kevin, I am curious 😀. Hi Kevin!!! I am your fan too!! Greetings from Caribbean, Puerto Rico!!!
Do you have a video or recomend a video that help me intruduce to the side mount driving? Which are the advantage and disadvantages? Or video that help me understand and learn about tecnical diving!!! Thnks!!!
Thanks for watching Ramon.
I'll have to do a video on sidemount I guess. It's a very small portion of divers but there are lots of questions.
I don't know of any videos. The most common source of info on sidemount or tech diving is the internet or an instructor.
Take care.
Alec
Alec as you mentioned when the first stage fails the reg will free flow. Now what will happen if a BCD Lp inflator fails? Will it fill the BCD with air or will it totally cut off your air to your BCD? Thanks in advance for the info and another great video
BCDs are remarkably reliable but there are 2 areas of concern.
1. The PIV (Power Inflator Valve on the end of the BCD big hose) will deteriorate over time if not fastidiously care for. If it fails it usually either leaks air to the water or leaks air into the BCD. In some cases it fails to provide air at all. None of these situations is good but, having become dependent on the ability of the BCD to maintain our buoyancy, divers faced with a BCD that slowly fills throughout the dive find it annoying at best and potentially dangerous at worst. While a BCD that won't fill sounds bad, assuming the diver is properly weighted, it's not usually life-threatening. These valves should be serviced as often as your regulator. If it is not cleaned regularly it can become so badly corroded that the only solution is replacement of the valve (not the BCD - just the valve for less than $100).
2. The LP hose can also be a source of problems although less often. Inside the end of the hose is a Schrader valve just like the one in a bicycle tire valve. These will also corrode if not rinsed and few people do that consciously. It's usually done while rinsing the regulator itself although if you're in the habit of rinsing your reg under a tap or hose rather than giving it a good soak, this valve doesn't get touched. If that little $0.10 valve fails you get no air. It should be replaced at every regulator service (less than $10). Also in the same spot, there is a small O-ring that seals the spigot on the BCD main hose into the LP inflator hose so the air won't leak out. I have never seen a dive store that regularly replaces that O-ring although it is even more subject to sun, heat and salt that the tank valve O-ring. The reason is simply that It's a real nuisance to replace. If not practiced at replacing it, service staff can find it frustratingly difficult to get to and to insert a new one. Insist that it be done with the Schrader valve change.
Good question. This might be a good Tech Tip topic.
Thanks.
Alec
Hi Scuba steve, usually a BCD will leak before something will happen to your bcd. As Alec Peirce scuba says it needs yearly service.
Hi Steve, Watch this video on how to service the LPI schrader valve, S06E05 Servicing Your Inflator Hose, th-cam.com/video/yaXyn4-cxKs/w-d-xo.html
Thanks for the suggestion. I will add it to our ideas list.
One more question...how would you do the adjustment on a environmentally sealed 1st stage reg? As per one of your videos, I understand that the adjustment bolt would be under the rubber boot that is filled with liquid.
In this case you'd need to check the service manual where it will explain how to do this adjustment. That's assuming the manufacturer allows service manuals to be given or sold to customers... some do some don't.
Thank you Sir
Most welcome.
A
Hi Alec, I'm having difficulty understanding regulators.
Is the IP always Ambient + 150psi (approximately)?
So in the shop the IP is 150psi, ambient is 0psi gauge pressure;
At 30 meters/99ft, ambient is 3x15psi = 45psi; IP would auto adjust to 150psi + 45psi = 195psi?
How can we safely breathe air that's 150psi higher than our surroundings?
How does this affect our BCDs and drysuits?
Presumably it must be something to do with the low flow rate?
Really great videos by the way, I'm new to your channel and I'm a big fan! You have a great manner on camera, very engaging and knowledgeable. Thank you!
yes, IP is ~150psi+AP, that's why it has openings otherwise that wouldn't be necessary
How can we safely breathe air that's 150psi higher than our surroundings? - 2nd stage reduces it to IP ambient. Diaphragm is "preloaded"with AP and then you create under-pressure by breathing in, which gets equalized by the lever opening and letting in air from IP pressured hose, because the diaphragm presses on that lever (Alec also has a video explaining that, prbly better)
How can we safely breathe air that's 150psi higher than our surroundings? - higher IP would mean faster inflation, but you shouldn't have to full press the button anyway
hope that clarified it, otherwise have a look here: www.thoughtco.com/how-does-a-regulator-work-2963185
Yep! IP is ambient +150 (or whatever the factory setting for IP at surface is supposed to be - 125psi to 160psi).
You've answered your own question. The IP is balanced at ambient. That is, no air comes out of the reg at any pressure or any depth until you inhale. Then the air that comes out is the correct pressure to fill your lungs as you inhale. When you stop inhaling (lungs full?), the air flow stops. Your lungs will only accept air until the pressure inside equals the pressure outside. They will not overinflate - unless you block the windpipe somehow.
If the air pressure was equal to ambient i.e. not 150psi above ambient, you would not be able to inhale. Your lungs have virtually no ability to suck air as you can prove by trying to breathe through a long tube (say, 4' long) while sitting on the bottom of the pool.
Hopefully, this is clear.
Thanks for your question.
Alec
Thank you!
You're welcome!
hi Alec, I noticed on on some older regulators that the yoke has threads where it connects to the 1st stage, what are they for?
Yokes are pretty much universal in design and fit. However, how they attach to the regulator varies between manufacturers.
Most attach by means of a yoke nut. The yoke slips over a threaded stem and a nut threads onto that stem to secure the yoke in place. Other combine the nut and the threaded stem into a single bolt that fits into the yoke and then tightens into the reg body. Another less common arrangement has a long threaded stem onto which the yoke, also threaded, screws. The yoke is not tightened down in this case but is held from unscrewing by a large C-Clip. I suspect this is the one you are looking at since in this style the threads are quite visible. I'm guessing it's a US Divers regulator. They used that system for a long time.
Thanks for watching.
Alec
Legend 🙌
Thank you.
A
Thanks Alec. Question: I feel that my newly bought overbalanced diaphragm regs release too much air. I run out a lot quicker than I used to with basic rental piston regs. Will it help if I reduce the ip on the first stage? My second stage comes with an flow adjustment lever and even at the lowest mark I feel theres still too much air flow with every breath.
There could be many factors affecting your air consumption, not just the regulators. As for reducing the IP, don't. The manufacturer set the IP range to be ideal for diving, changing it yourself without knowing the effects is not safe. Look for my video on setting breathing resistance # S08E01 as breathing effort is set at the 2nd stage, not the IP.
Take your regs to your local dive store and discuss your concerns with them and have the adjust the 2nd stage breathing while your there for you to check until you find a setting you like.
Thanks for watching.
Alec
So what if you are mixing and matching first and second stages with different factory recommended IPs? Do you set the first stage to the factory IP and adjust the second accordingly, or do you set the first to match the factory IP for the second stage so it breathes well?
Always set the 1st stage as dictated by the manufacturer. It is determined by very specific requirements.
Then simply adjust the 2nd stage to suit your breathing needs, light enough to provide air easily but not enough to create free flow.
There is no "setting" for the 2nd stage, It is adjusted to the IP coming from the first.
Alec
Hi Alec, I have a question for you: Now that I am an OWD thanks to your advice I got my mask and snorkel, but I am seriously considering buying a pair of fins, more precisely a pair of split fins, but I have 2 doubts the first one is the size of the foot pocket ( I am size 9.5 US) so do I need to buy it in a regular size or in a large size, the other doubt is about which fin is better I am deciding between the Scubapro twin jet, the mares raptor, and the oceanic vortex and the TUSA SF15 expert I saw some of your videos with some of that fins, so I want to know the quality of them, and what fin do you prefer. Thank you ( I had a good pair of aqualung splash jr split fins and I loved them but now they dont fit me, I also tested other normal fins but I still prefer the split ones) This time I dont care about the price once again thank you.
Hi Piolo! Awesome that you got your OWD now! I would buy a Large size when you have 9.5 us size, especially when you want to wear shoes with big soles. You also can look for at the Atomic split fins: www.atomicaquatics.com/splitfins.html
50ft Below Thank you mate! :)
Hallo Alce , I have tow Scubapro First Stage MK20, the intermediate pressure is different between them , one of them is 9,6 bar and the other one is 10,4 bar , is that normal?
I found a good answer on www.scubaboard.com. I know a lot but unlike my wife who knows everything, I also have to do research. This is a great resource to ask questions to the global scuba community. DA Aquamaster posted this answer:
It is a Mk 20 specific problem. The Mk 20 had three different piston designs depending on when it was made.
1. The early piston was a stainless steel piston with a knife edge seating surface. It worked great.
2. The mid production Mk 20 used a brass tipped piston that had a rounded seating edge. They were notorious for having a mushy lockup and IP creep and in fact have a much looser set of allowable specifications for IP creep. A "normal" piston is expected to lock up very solidly with little or no creep in the first 5 seconds and none after that. The Mk 20 was allowed about 5 psi of creep initially and a few more psi over the next minute. I pretty much replace them on site as it is a "when they fail" rather than "if they fail" issue.
3. The late production Mk 20 used the same composite piston used in the current Mk 25. It also has a knife edge and locks up very solidly. It is a direct replacement part and the dealer cost is about $25. I it also replaced free under warranty if the IP will not lock up.
If you do not have a brass tipped piston, I suspect the seating surface is damaged so piston replacement is still the most likely fix.
NOTE: read the full postings here: www.scubaboard.com/community/threads/scubapro-mk-20-pressure-creep.245312/
@@AlecPeirceScuba_SeaHunter thank you so much Alec , I will have a look on it.
Why does my piston first stage singer or whistle when I breath in until the tank pressure gets to around 2000psi. After that it stops singing.
Does it play a tune you know? But seriously, a high pitched whistle while inhaling is a sign the 1st stage needs service as the o-ring around the piston is likely wearing. As tank pressure drops the noise drops due to the pressure on the piston reducing and the speed it moves up/down is slower. It's still usable but your buddy may get annoyed. Thanks Mike.