Servicing Your Tank Valve - Scuba Tech Tips: S05E06
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- เผยแพร่เมื่อ 27 มี.ค. 2017
- Every diver uses a tank valve, but do you know what it takes to service it? Alec shows what is involved to fully service a scuba tank valve for those who own tanks or to understand what a service professional does for you.
**** Alec Peirce Scuba ****
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Nice to see you back! Great video!
I really enjoy your tech tip videos, thanks for all the effort and time you spend doing them.
Thanks Alex some good info, and it reminded me I have to service one of my 15ltr air tanks which is faulty and stored in the cupboard......
Thanks! I am currently on my journey to becoming a dive pro, and I hope to be servicing tanks as part of my duties. This was really helpful! I will, of course, get proper training as well.
Good luck.
Thanks for watching.
Alec
great video - learned something new and I do own my own tanks :)
Glad you enjoyed it. If your tank knob seems really hard to turn, now you can take it off and lubricate the stem. Saves money and may save a dive. Alec
great video,,,,,,,,,,great tips
Great video. I am not a diver. I shoot high powered air guns that fill from 3000 all the way up to 4500 psi. Airgunners like myself use scuba and carbon fiber tanks as fill stations for our guns and we often own our our compressors to fill our tanks with. Great to know how to service our valves.
I have filled hundreds of air gun tanks. We had one chap who had some pretty impressive guns (I'm an active hunter myself with 8 World Record animals in the book, but not air guns). He purchased a couple of them in Europe, Austria or Czechoslovakia I think, that cost $2500!! I helped him to make some adapters to ease the process. Most dive stores weren't able to fill them until he came to me. I set up a short (30 meter) range in the dive shop so we could shoot after hours. Lots of fun.
Take care.
Alec
Great video
Glad you enjoyed it Josh.
Thanks big al !
Any time!
A
thank you for this tip. I let my dive shop service my tanks
Grat stuff thanks
Glad you enjoyed it
Thank you both, very int. video and keep em coming. I would not service my own gear, for that I have an excellent dive store near by. Sadly he is old like you (he he just kidding) he is still young but getting older, and i fear the day he retire. Both as a friend, master instructor and a service person. Still I rather would find a professional to service my gear, just to be safe. But I wonder, how do you get to be a service technition, is there a school or cours for it?
Mr Alec I would like ask a clear question how it’s necessary to use go & no go thread test for every time visual inspection? Pls answer me with reference thank you
fascinating!
Lots more to learn Raquel.
Another great informative video! I have three S72 tanks rated for 2250. I recently put pro valves on these tanks but it failed the recent VIP due to the burst disk being overrated. What should the rating be on these burst disks?
OK. Let's be clear. A tank won't fail a Visual Test because of the valve.
I assume you mean the valve service or examination failed because of the faulty burst disc.
In that case the service center should have simple replaced the burst disc - $10 - problem solved.
What happened here??
FYI, the proper burst disc for a 2250 steel 72 has a rating of 3750psi (I think that's right, without checking).
Alec
Great video Alec. Quick question- would silicone grease be ok to put on what you call the fork (so that it spins more smoothly when turning the valve)? I find that christolube makes it terrible to turn compared to grease. But does that grease ever come into contact with the gas..which would be a hazards when partial pressure blending?
Christolube can be very sticky. Unfortunately, the fork in most valves does come in contact with the tank contents or whatever is flowing into the tank, which with Partial Pressure fills, is pure O2. The O-Ring seal & Silicon Back-Up washer that allows the valve knob to turn without leaking are both located on the fork stem. You really need to use oxygen-compatible grease. The other place where a VERY thing layer of grease might help is on the actual fork itself where it meets, fits onto, and turns the valve seat. And be sure the valve seat turns smoothly as well.
All of these areas can contribute to a hard-turning valve and all of them require the proper grease if you're into NITROX.
Good luck.
Alec
can you please talk about how computers works regarding deco stops, for example a diver got distracted and the computer doesn't allow you to go up and you need to do a deco stop. regards.
Hi Alec, Hope you are doing good. Nice Video.
Recently I bought my first Aluminium Tank from the only dive store we have. The guy just put valve on cylinder and just hand tight it; no lubrication/silicon and didn't wrench tight the valve. I am worried if this is enough and should be done like this?
Please suggest
Not uncommon. There may have been things that you missed.
But here's the correct process:
1. inspect the tank interior, the tank threads and O-ring seat using a proper instrument (hopefully more than a
flashlight and dental mirror)
2. inspect the valve threads.
3. install a new O-Ring without lubrication (assuming the O-ring is new and fresh)
4. LIGHTLY lubricate the bottom (beginning or first-in) threads with appropriate lube (O2 compatible)
5. carefully thread the valve into the tank until hand tight
6. torque to manufacturers specifications (usually about 45 foot-pounds)
Many dealers don't bother to inspect new tanks and valves - big mistake!
Many dealers still lubricate the O-ring but not the threads - big mistake.
Many dealers install the valve hand tight but hard, maybe using a rubber hammer to seat the valve against the top of the tank. This approximates the correct torque and is probably ok. It takes time to properly torque a valve and a special wrench as well as a torque wrench is needed to do so. Most have a torque wrench (I hope!!) but few have seen nor have the special wrench that fits over the top of the valve to grasp it for torquing.
And lastly, a good service area will do this in the privacy and quiet of the service area - away from the customer, not to hide anything but to ensure uninterrupted time to concentrate and do it right.
You asked!
Thanks for watching.
Alec
Great video. What about info on the tank valve opening? Isn't there's an o ring behind the opening on the face? I'm trying to stock my save-a-dive box with o rings for the tank valve, but I don't know much about the ring inside the face opening. Can that be changed easy? Thanks!
I'm pretty sure changing that ring is covered in a video Rick.
It's very easy, very important and those rings ought to be in your kit even if diving with a charter boat that supplies the tanks.
Take care.
Alec
Hey Alec, Thanks for a great vid! Quick question... can i use Vaseline as a lubricant? Its 100% pure petroleum Jelly
Never. Petroleum jelly is NOT a lubricant and is absolutely not compatible with enriched air (nitrox). Use only scuba approved silicone (spray or grease) or tribolube and christolube products. There is lots if information on www.scubaboard.com on this subject so I suggest going there are read for yourself why it's an absolute no.
A
Alec, thanks for the video. I think you should have mentioned, that tanks MUST stored either full or empty, since a partial filled tank, the over pressure release valve would not operated unless thank is full, and in case of a shop or boat fire, the tank will blow up, like I saw in a tank down in Roatan once.
Well, unless I misunderstand your post Michael, you are partly right. The overpressure or safety relief valve (which is really a burst disc) works on pressure so it won't activate unless the pressure exceeds the maximum. It's designed to prevent a tank from exploding from high pressure.
On the other hand, a tank shouldn't 'explode' or blow up as you say, unless it reaches a high pressure so a partially filled tank ought never explode.
Alec, I meant, in case there is a fire, a partial filled tank would explode, since the burst disk, will never activate. If tank is empty is no problem. If the tank is full, the burst disk, should activate, long before the tank explodes in a shop, boat, house fire.
Gosh Michael. A fire or high heat shouldn't necessarily cause an explosion. A tank blow up or explosion would only result from too high pressure and a fire shouldn't cause that much pressure increase, particularly if the tank wasn't full to begin with.
It's been guessed (no real figures available) that a tank would withstand maybe 10,000psi before the tank explodes. That's why we have the Burst Disc.
An aluminum tank might be damaged by high heat since heat can affect the metal itself and weaken it but even then it's not likely to blow up if the tank was at low pressure to start with. Aluminum tanks that have been exposed to heat of 350 degrees cannot be refilled or even tested. They are condemned.
Here's some math for you:
A scuba tank will increase in pressure by about 5psi for every degree of temperature increase. Thus a full tank (3000psi at 70 degrees) would increase to about 3500psi in a car trunk at 140 degrees. The burst disc for an aluminum 3000psi tank is designed to burst at 5000psi. While the burst disc can be out by as much as 500psi we're still a long ways from 3500psi.
However, a wood fire is between 600 and 1100 degrees (1100 in the hot coals) and that would cause a major increase in tank pressure to about 6000psi. The burst disc would blow at about 5000psi so the tank would not explode.
I hope that has completely confused you Michael, but also supplied some ideas.
Alec
" I meant, in case there is a fire, a partial filled tank would explode, since the burst disk, will never activate."
Miguel, your understanding of how a burst disk works is incorrect. It doesn't burst if the pressure increases by a given amount above the base pressure, it will burst if the pressure exceeds a fixed amount (plus or minus normal variations) regardless of starting pressure. If a tank would "explode" at, for example, 10,000 PSI and the burst disk would rupture at 5000 PSI, it doesn't matter if the tank was at 3000 PSI to start or at 1000 PSI; in either case, the disk would burst at the same pressure, which is less than the tank's failure pressure. What would cause a tank to explode in a fire isn't that it was only partially filled, but that some flaw was present that caused it to fail below the burst disk's rupture point, and that would have happened whether the tank was completely full or only partially full to begin with. It could also happen (in theory) that the tank pressure continued to increase faster than the burst disk's orifice could release air, but that would be a very rare condition.
very educational. i like these vids. but the servicing cost here are the same as a new valve. many people even dont service there 1 & 2 stage because of the prices. valve servicing 30 euro, and 1&2 stage 100 euro. thank you for these nice vids.
Alex what do you know about Aqua Lung MK /LV2 egress air tank can you use a Spare Air refill valve or other brand on the Aqua Lung tank to refill the air. Aqua Lungs refill is $200 dollars. Do you have any videos on these type of tanks ?
That system uses an integrated tank valve and 1st stage. That is, the tank valve IS the 1st stage. Consequently you cannot attach the Spare Air adapter to it for filling.
It could be done but would require some jury rigging by modifying the pressure gauge attachment point. That's the only access to high pressure.
Aqua-Lung has a habit of producing products that are unique and that can only be used by and serviced by them. Generally those products do not last long in the market but they continue to try.
The system is very specialized and not really of sufficient interest to recreational divers to warrant a video.
Stick to the good ol' Spare Air I'd say.
Take care.
Alec
Alec I have a J valve from an older model steel tank I bought. The tank passed Hydro but the Valve was leaking. I see your video on the valve kit but I wanted to know if I need to worry about a leak in the reserve knob side, Also the burst valve does not seem like a regular burst. No hole on the side. any advice?
It's easy to service a valve. It's best done by your LDS (have to say that and I believe it too) but you can do it.
Depending on the valve brand, the reserve side will be sealed by an O-Ring or a copper gasket just like the knob side. Try to find a parts breakdown for your model on-line.
Replace the gaskets and O-Rings and put the nuts back in place well tightened. They must crush the copper gasket so it takes a good solid tightening to do so.
You may have a very old burst disc style. Does it seems to have a small, gray, raised, bump in the middle of the nut? If so, it's very old. That bump is actually a lead alloy plug that's forced into the nut. Under enough pressure and/or heat the plug will fly out - like a .22 bullet!
You may be able to replace the old-style burst disc with a newer model. Only your LDS can help you decide this. Take it in , have them remove the old burst and see if a newer style will fit.
Don't spend too much money. I have good valves, K and J for sale on my eBay page for about $20 - search for my eBay ID seahunter!
Hi Alec, Great video series.
I just purchased a new Catalina 80 Alu tank where I want to replicate my old US Diver 80 Alu from the 70's with new decals. Should be a conversation piece.
Here's my question: The original USD J-valve is cosmetically in great shape and still on the old tank with 200~300 psi still in it and has not been used in 30 years.
Can its J-Valve be serviced and used on the new tank?
You can find online J valve kits or newer ones. Would recommend using a new tank valve with the handle indicator (shows open/close) than use a J. I'm assuming you're diving with a computer or SPG so you know the tanks pressure, no need for the J unless vintage diving with others who are knowledgeable about its operation. I used J's when they first came out but stick to new tank valves and computers for reliability and safety. If you can get the J serviced and installed, it will be a good vintage setup with other vintage divers. Good luck.
A
@@AlecPeirceScuba_SeaHunter Will do. BTW, I've always had a SPG since 1974 even with the J-valve. I bought an Oceanic PP3 computer about 4 years ago. Looking forward to perhaps meeting you some day.
Mr. Peirce, thank you very much for this channel! I have one question: ¿ why does a tank valve dosn´t fill?
Hi Cabo.
I'm not quite sure what you're asking. It looks like you're asking why a tank valve doesn't fill.
There are reasons why a valve won't allow a tank to be filled but the explanations are long.
Please explain what you would like to know.
Alec
Mr. Peirce, thank you for your answer: let me explain: I´ve a tank valve that when filling , down´t allow air to flow into the tank.
when opening handle, air goes out naturally out; then took off valve from tank and when blowing air flows normally; again attached it to tank, try to fill and same, air don´t get into the tank…
thank you very much for your time ,
best regards
Hi Alec, sometimes it is embarassing to admit doing something stupid but I am hoping to learn something from it! I removed the manifold from my twinset without emptying the air from one of the tanks (still had 50 bar). As you can imagine, there was a loud bang and the tank flew a couple of meters away (I learned my lesson). My question now is, due to the adiabatic effect I witnessed the very rapid cooling of the tank (took 5 seconds or so to completely lose its pressure from 50 bar to 1 bar)- can this affect the tank in terms of integrity or material property? (therefore requiring a visual or hydrostatic test)? I realised that the reason why the tank didnt explode like a rocket is because the opening at the manifold is small compared to the tank neck (if that was removed I probably wouldnt be writing this question!)
Sorry for the delay.
Thank goodness you are OK.
The lesson here is simple. Always be sure the tank is empty by opening all valves before doing any work.
I'm sure you have learned that lesson!!
The rapid cooling has little or no affect on the tank.
Extreme heat can be injurious to aluminum tanks but not cooling.
Take care.
Alec
Silicone washer, or teflon washer, after the handle? I thought it was teflon.
My tank valves (1 year old Dive Rite) are very tight and hard to turn when my twinset is full. They get better when tank pressure is lower.. What service can be done to improve that when full and allow for an easier turn?
There may be some slight difference but it shouldn't be much. If you notice it, it probably simply needs service. In my dive store (1969 to 2016), it always amazed me that divers did not want to spend $12 for a valve service after just paying $75 for a tank service. The valve works much harder than the tank itself and has many parts, lots under pressure.
A couple of O-Rings, maybe a Teflon washer, cleaning and it'll be like new.
Alec, do you recommend removing your pro valve insert after each dive and storing cylinders with valve detached?
The tank valve should never be removed unless for a visual inspection or hydro. It lets contaminated outside air into the tank which is a bad thing.
@@AlecPeirceScuba_SeaHunter Apologies, but My question was poorly worded. I’m talking about the screw in piece that lets you switch from din to yoke. You need an Allen wrench to unscrew it. I let a buddy borrow one of my cylinders For his DIN regulator and he could not unscrew it because it was so corroded.
I clean my tanks well, and a good way to avoid this is soaking the yoke insert in fresh water, any remaining salt will be gone
That was a very informative video, thanks so much! However, I hope you can find a cameraman who can follow the subject item that is being talked about and focus in next time.
That is not always Kevin's doing as I sometimes move in unexpected ways.
Thanks for watching.
Alec
Hello, after I replace the valve of the cylinder, there is a crash around the neck of cylinder valve. Could you tell me what exactly happened to this cylinder? the cylinder made of composite.
If you mean there is a crack around the tanks neck, there are several common reason why: over torque, dropping on the valve, defect and slow growth in cracks over time missed by Visual Inspection. No matter the cause, cracks must be checked and certified as safe or the tanks fail visual or hydro testing.
I need to do this to my tank, but unfortunately Air venturi say it voids the warranty. I cannot even open or close my tank unless I have a wrench. It was bad when it was brand new, now its even worse. I haven't even closed it or opened with any excessive force. Air venturi sucks.
Tank valves are the simplest gear to service. Any LDS can do it for a reasonable price and quick. Maybe time to change tank valves.
A
I guess this doesn't apply to J valves. As soon as I started loosen the nut holding the fork, air started hissing. I tried to disassemble as the knob is hard to turn on/off
Sorry no. J vales have a different internal configuration from the very common K values we us today.
I just had my tanks serviced and when I open the valve in one, it leaks out of that tiny hole in the burst valve. So I probably need a new valve?
If you spray soapy water on the burst disk opening and there are bubbles, the burst disk (or assembly), must be replaced. NO air should come out the burst disk. Don't use the tanks until services and checked.
A
What should the PSI of a burst disc be for a 3000psi AL80?
Burst disks are designed to burst at pressures well above the tank's working pressure as much as 40 percent above. For a 3,000 psi aluminum 80, that would be around 4,200 psi. To ensure the proper margin of safety, each burst disk must be matched to the working pressure of the tank on which it's installed. Thanks Robert for watching.
Why is a copper ring used instead of a silicone ring? What advantage does metal give when building that seal?
Great question Bill.
Copper has several characteristics that make it the best choice, maybe the only choice.
1. Copper compresses to form the seal. It is what's called malleable which means that it takes the shape of the sealing surface. So the copper gasket is pressed into both the valve body and the packing nut with considerable force and the copper takes the shape of both surfaces thus forming the tightest possible seal. it becomes essentially part of the assembly. The parts are as close to being welded together as possible but still can be taken apart. Thus it will withstand the pressure better yet can be disassembled easily.
2. Copper is elastic and will stretch up to 25% of it's original size and still seal. Scuba tanks change size and shape as they are filled and emptied and that regular change would soon destroy other seals since they do not stretch with the changes.
3. A metal to metal seal will not extrude as any other material would - neoprene, fabric, silicon, etc. All of these would extrude or be slowly forced through the crack between the two sealing surfaces. That cannot happen with copper.
4. Copper conducts heat better than most metals and certainly better than any other normal sealing material. The heat that is created in the filling of a tank could affect any other sealing material at this critical, full pressure joint. But copper, being a good conductor of heat simply lets the heat pass through it without any adverse affects to the seal or to itself.
This is why copper is still used for high performance engine head gaskets. All of the same factors apply in that situation as well.
Oh, BTW, they're cheap too.
I hope this has answered your question Bill.
Thanks, Alec
As I read this, the metallurgical properties of copper become apparent again! Thanks for the detailed refresher.
Yep! Copper is pretty amazing. If you think about it, the properties of copper are remarkably similar to another well known metal - gold. Malleability, elasticity, heat and electrical conduction, etc. plus both metals polish to a brilliant shine. Copper was once as valuable as gold to ancient metal smiths.
As an aside, my son is a miner in one of the largest copper mines in the world right here in Ontario. It is the deepest mine in the world at 9880' feet below sea level. That's just under 2 miles!! He works at the bottom!
Talk again soon. Alec
Holy guacamole...
Alec I know you will not agree but that copper washer can be reused. Just heat it up with a blow torch and it will be like new. Same thing on the copper washer on your car oil plug...
Tell the complete story at the time when telling its possible. If you would like to re use a copper washer you need to heat it to "cherry" red and quickly cool it down in cold water. At this time it will get some flex back. If you ket it air cool it will harden and will be unusable.
Unless a steel washer what will harden when cooled quickly and soften when cooled gradually.
Bas you are completly right.
Come on guys...! Is it that expensive to buy a new one? Unless u are in a very very remote island and far from 7e😬🙈✌🏻
Off to service my own now. Wish me luck 😅 jk great videos
You can do it!
A
What is proper technique for opening and closing the tank valve. Hear-tell they should be used in the fully open and fully closed positions. Also hear-tell that in the fully open position they should be backed-off 1/4 - 1/2 turn???
Scan through my past videos for tanks but valves should be fully open, finger tight only. Back in the old days, the 1/4 back was to prevent the tank valve from seizing up. With todays modern materials and precision manufacturing, that is not a problem. Anyone requiring the tank valve to turn back 1/4 turn should re-examine their logic. For a positive, visual indication of tank open/close, look at my Vindicator tank valve video.
Thanks for watching.
Alec
I wish you would go more slowly and more up close camera shots.
We move in/out/don't move and get similar comments. Sorry we can't meet everyone's viewing needs. Was the content OK to get an idea of what a service pro does?
A
Hmmm.... those are not silicon rings. The white rings are made of teflon for friction free movement. Anyone who knows whst they are talking about would know that. Your 45ftlb torque is way higher than hand tight and it should be about 80ftlb for valve fitting. You are giving out dangerous information. You shouldnt post about things you dont really understand.
My 45ft/lb of torque comes from the Sherwood valve installation guide. Tank valves seal with no more than hand tightening. Beyond that is to ensure they do not work loose. 80ft/lb of torque is greater than the torque of my wife's wheel nuts!! Much too high for a tank valve.
However, different tank valve manufacturers may have different values although not much. The threads are identical, the material used to make the valves is identical, the O-Rings are identical and the tank material is identical.
Here's a link to the Catalina website which details the correct method to remove, clean and re-install a tank valve. They suggest that hand tightening 1/8 turn past O-Ring contact is fine. If one prefers to use a torque wrench, the recommended torque is 40ft/lbs; maximum torque is 50ft/lbs.
www.catalinacylinders.com/faqs/valving-of-scuba-air-cylinders/
In my 50+ years in the scuba service industry, I had a lot more problems with overtightened valves than with loose valves!
Many tank O-Rings, both the valve neck and the valve face, are still made of rubber (Nitrile).
Silicon O-Rings are quite common in many scuba applications but now more for camera housings, lights, etc. They were used for some time for the tank valve face but not so much now. Silicon is subject to deterioration by sunlight. It turns yellow and gets stiff.
Teflon is much too hard for use as an O-Ring. It would not extrude or squeeze to seal the gap as required by O-Ring material. Teflon was used on the valve face for a very short while years ago (pre-70s) but was quickly discontinued. It needed a great deal of pressure to seal the reg on the face of the Teflon so it soon wore out. Teflon rings, more like washers, are used throughout most regulators on swivel joints because of its lubricating qualities. However, because it does not extrude to seal a joint, it often needs a true O-Ring beside it to create the seal. In that application it is referred to as a back-up washer. Here's a link to the Trident Dive catalog showing some typical valve rebuild kits. You can see some flat Teflon washers but the neck, face and shaft seals are Nitrile O-Rings. These are changed to Viton if the tank will be used for enriched air.
online.fliphtml5.com/tzzi/iaqr/files/large/13.jpg?1538501874
The white ones that are still in use today are polyurethane characterized by their yellowing when exposed to light. The yellowing BTW, does not degrade their performance. It just looks yucky.
Neither of these 2 materials are resistant to oxygen.
The 2 other materials used to make scuba O-Rings are Fluorocarbon Elastomers (Viton) and Ethylene Propylene (EPDM).
Whew! I hope that clarifies the information about tank valves satisfactorily. It is as I said in the video.
I'm far from perfect Richard but if there is one thing I do understand, it's scuba service.
Thanks for watching and keeping me on my toes.
Alec
@@AlecPeirceScuba_SeaHunter What a tactful reply to snide comment. I see why you're still happily married after many years.
You’re a clown bro 🤡🤡🤡
@Anthony Boyette Where are you coming from , man. I've made no such comment. Why jump on me and call me a jackleg. I agree with Alec. The Torque doesn't seal the valve on the tank. The o- ring makes the seal. Minimal Torque specified is all that's needed.
You talk too much and way too oppinionsted
Lots of other videos to watch, still may learn something.
@@AlecPeirceScuba_SeaHunter I do learn, or should I say re-learn, alot from your vids, I've just gotten a little impatient as I age I guess. I prefer gettin to the point of things and don't really care about all the roundabout o get there. It shouldnt matter to me anyway. I learned in 1979 or 1980 @ an NASDS establishment and got to advanced open water. Had a few hundred dives until 2011 when i became blind. Now I've gotten some sight back but no longer have my card, log book, tic card and it's been so long I can't get anything replaced, since there is no NASDS any longer. Yeah, SSI aint no help.