New tanks how... to install the valves

[D1v1n]

I ordered a set of new pst e8 119s and need some advice. The tanks are coming via fed ex ground and have the Pro-Valves removed. They come with the visual inspection. Do I just screw on the pro-valves? How tight? etc.. And are their specials seals, teflon tape, etc. The directions are probably in the box, and these were all great questions I should have asked prior to the purchase. If it is something the LDS should do, I will do it, but if I can save few I will try. Thanks in advance for your help.

 

[H2Andy]

yup, screw them as tight as you can by hand. don't use a wrench.

then leave them alone

 

[Dive4Life]

Can you successfully install a light bulb? If so, then you are more than capable of installing a valve. You should tighten the valves as much as you can by hand. Tightening them more than necessary with wrench stresses the threads. Watch for cross threading, this could destroy the valve and possibly render the tank useless.

 

[aa777888]

Hand tight? I know it's a PST tank, but for example here is what Luxfer recommends, and it isn't hand tight (BTW, Luxfer has all their tech manuals (inspection guides) available for download at http://www.luxfercylinders.com/downloads/):

The application of a small quantity of lubricant to the valve threads is essential for
the proper care of the valve and cylinder. We recommend that only Dow Corning
Compound 111 be used on valve threads.

Only a very small amount of the lube is needed, and only applied at the bottom of
the valve threads. The lubricant will ride up the threads as it is installed. We only
recommend this lubricant since it has proven compatible with cylinders and valves,
doesn’t add any grease or oil to the cylinder, is safe to use, and helps prevent galvanic
corrosion.

WARNING: Never use any kind of tape wrap, oils, vaseline or petroleum
products on valves installed into high-pressure Luxfer Gas Cylinders scuba
cylinders.

We recommend that all straight thread valves be installed in Luxfer high-pressure
aluminum scuba cylinders with a torque recommended by the valve manufacturer
for aluminum cylinders.

Without a recommended torque from the valve manufacturer,we would recommend
a torque of 50 lbf-ft, plus or minus 10 lbf-ft. All torquing should be done such that
valve, valve components and cylinder are not damaged.

50 foot-pounds is a lot more than hand-tight. Maybe you should give PST and/or the valve manufacturer a call.

 

[scubatoys]

Luxfer also says do not partial pressure fill nitrox in one of their tanks, do not fill them any faster than 300psi per minute, do not put them in a water bath when filling... and on, and on.

I've been in a whole lot of dive shops - and never once seen anyone put anything on the threads, or pull out a torque wrench when installing valves. Just tighten hand tight, then just pop the valve handle with the palm of your hand to go just past hand tight. Kinda' like your kid took your car without permission... scratched it, but your in a public place.... Hit the valve that hard.

Keep in mind, you screw on your reg just finger tip tight, and that uses a much smaller o-ring that is not threaded into place - and that stays there under the same pressure as the valve.

 

[japan-diver]

I've been in a whole lot of dive shops - and never once seen anyone put anything on the threads, or pull out a torque wrench when installing valves. Just tighten hand tight, then just pop the valve handle with the palm of your hand to go just past hand tight. Kinda' like your kid took your car without permission... scratched it, but your in a public place.... Hit the valve that hard.

.

Have to disagree, Have been in a few shops myself over the years and haven't seen valves installed without some 111 or something on the threads, maybe its an Asian thing??? I do agree not to many torque wrenches on the valves though- hand tight and pop or a nice pull on a wrench is all.

If you put some 111 on the valves they will come off much easier next time you viz the tank.

 

[DA Aquamaster]

I would not use Dow 111 silicone if you intend to do partial pressure nitrox blending as despite what Luxfer indicates with regard to it not introducing grease or oil in the cylinder, it will not maintain an adequate O2 standard (in my admittedly limited and conservative opinion).

I am however a believer in lubricating the valve threads. The goal is not just to make things go together better but also to offset and/or prevent the potential effects of dissimilar metals corrosion in aluminum tanks. Consequently on my AL deco bottles I will lightly lube the threads with Christolube and have no far encountered no problems. If you are not lubricating your valves, the oxidation you are finding in the neck has nothing to do with salt water exposure.

On steel tanks I think it is less critical as dissimilar metal corrosion is not a factor, but a little lubrication still helps keep the chrome plating on the threads intact and leaves the valve in a much better condition to be used on AL tanks in the future.

As for torquing the threads, too much is a really bad thing for the tank and with an AL tank can lead to cracking or thread damage in that area. On the other hand, not enough torque is not an issue as long as the valve is at least hand tight. Once the tank is pressurized, the valve is not going to turn and as long as there is not excessive space for the o-ring to extrude, the seal is not going to be compromised. So if you don't have access to a suitable torque wrench and crow's foot, err on the lighter side with the "just past hand tight" approach.

 

[MikeFerrara]

The problem you may run into doing it yourself is that many shops won't fill a completely empty tank without performing a visual inspection on it...The thought is that if the tank is completely empty it may have water or some other contaminant in it.

I have recieved new tanks directly from the manufacturer with VIP stickers on them that had manufacturing defects and had to be returned to the manufacturer for replacement. I wouldn't put the valve on without dropping a light in and getting a look at the inside and using a mirror to get a look at the crown. It only take a few minutes but manufacturing and inspection processes aren't perfect so it's worth doing.

 

[CD_in_Chitown]

....It only take a few minutes but manufacturing and inspection processes aren't perfect so it's worth doing.

Ditto, have them re-VIP'd

 

[D1v1n]

The first tank came in today. The valve was already installed in the tank, but the tank was empty. I appreciate all of your ideas and input.