Question regarding tank fills

[Divin'Papaw]

My only issue with a water bath is if they don’t purge the whip abs the valve before they couple it, they will blow water into steel tanks.

That’s not an issue if they do it right. Personally I’ve never had any of my HP100s fail VIP or even need to be tumbled or whipped. I have 4 HP100s that are regularly filled this way. So far so good. My experience is only with Force-E. I can’t speak for other shops.

 

[SlugLife]

Checking your own tanks is absolutely the responsible and smart thing to do. However I strongly disagree with those suggesting the responsibility/obligation should be on the customer to do that. You're paying for a service, and that service should be done correctly. Do we also need to have our own carbon-monoxide testers, oxygen testers, etc?

Start applying the above to any and every other service, from oil-changes, to medical service, to packaged goods, gas-stations, to prescription-lenses, to .... I mean that standard could be applied to pretty much every service. Quite often the customer doesn't have the tools, expertise, or time to double-check the work done.

I'm surprised that you get that much pressure drop. 3 hrs is a long time. It takes me 20-25 min to fill an empty 3500 with my compressor. I take it to 4K and it usually ends up around 3600 when cooled (still learning though). The tanks (even filling 2 sets of doubles) are noticeably warm. Not hot, but pretty warm.

Before the compressor I told the LDS multiple times they were shorting me.... he said it must be my gauge I checked with another and read the same thing. @ $12 / fill you'd think they'd make darn sure it was topped up. 3500 would usually be 3100, but they would hot fill to 3500 and that's it.... not a psi more. I disliked that shop anyway.

The whole "support your local diveshop" concept pushed over-and-over-and-over annoys the hell out of me. You run into similar in many other industries and hobbies too, from dance studious, musicians, bars, restraints, etc. I reject that concept & choose to be smart with my money. If my LDS treats me well, then by all means, they may earn a consistent customer & I may refer my friends. But not every LDS deserves a sort of blind-loyalty. People who create online businesses are also people too, and may be good or bad people too.

When C19 hit, a BUNCH of local businesses absolutely ripped me off. If I bought early-bird tickets, or did something like pre-purchase 10 classes, pretty much every business too the money, no refunds. I pretty much lost interest in another hobby because of that, after 6/6 of those businesses basically just took the money, and I suddenly found myself out about $1000.

Sometime in the next year, I'm planning on setting up my own fill station.

 

[DandyDon]

Checking your own tanks is absolutely the responsible and smart thing to do. However I strongly disagree with those suggesting the responsibility/obligation should be on the customer to do that. You're paying for a service, and that service should be done correctly. Do we also need to have our own carbon-monoxide testers, oxygen testers, etc?

I agree in theory, but in the current practice, I'm afraid it fails. DAN, the agencies, and the leading long-term vets & instructors of the sport are still ignoring the problem as long as they don't get busted. OW classes teach students to smell & taster their air as worthless as that is. Fake teaching to support the business.

Padi used to require that fill stations submit results of quarterly tests. They didn't bother enforcing that tho as they didn't want to lose shops & business, so they dropped it. Giving in to support income. Quarterly testing is just a snapshot shot at the best time, but ask those accredited labs how many tests failed. 3%. Sounds like a low number but if your tank had a 3% chance of being toxic, possibly injuring you, would you dive it?

As long as DAN, the agencies, and the leaders ignore the risks counting on not being discovered, and CO hits are difficult to expose after the fact, your gas safety is totally up to you. Go inspect a fill station as ask them where the CO monitors are, then listen to their excuses for now having one.

 

[halocline]

The cold water bath helps immensely with filling HP tanks quickly. I use them regularly for HP fills

Not as much as people tend to think. It's the air temperature inside the tank that matters, not the tank itself. (I'm sure you realize that, just clarifying for the thread) If you fill a tank in a cold water bath, it will help to keep the tank itself cooler, but unless you leave it in the cold water bath for a long time after the fill, the air inside will still be hot. If you do leave the tank in the water bath after filling it will definitely help cool the air quicker than just leaving the tank in a room. But during the fill and immediately after, when they test the pressure, the air will be just as hot (or close) and so the pressure will read high.

The only way to get a true accurate fill is for the shop to top off a tank after the air has cooled, then let that cool as well, then test it. Some shops will overfill while it's hot and they usually have a decent idea about how far they have to go over pressure so it will cool to working pressure. But so many just fill quickly to pressure and then you get a short fill. It's annoying.

 

[Divin'Papaw]

Not as much as people tend to think. It's the air temperature inside the tank that matters, not the tank itself. (I'm sure you realize that, just clarifying for the thread) If you fill a tank in a cold water bath, it will help to keep the tank itself cooler, but unless you leave it in the cold water bath for a long time after the fill, the air inside will still be hot. If you do leave the tank in the water bath after filling it will definitely help cool the air quicker than just leaving the tank in a room. But during the fill and immediately after, when they test the pressure, the air will be just as hot (or close) and so the pressure will read high.

The only way to get a true accurate fill is for the shop to top off a tank after the air has cooled, then let that cool as well, then test it. Some shops will overfill while it's hot and they usually have a decent idea about how far they have to go over pressure so it will cool to working pressure. But so many just fill quickly to pressure and then you get a short fill. It's annoying.

All I can say is it makes a difference. I have zero doubt. I’ve experienced it first hand over and over again.

 

[boulderjohn]

Checking your own tanks is absolutely the responsible and smart thing to do. However I strongly disagree with those suggesting the responsibility/obligation should be on the customer to do that. You're paying for a service, and that service should be done correctly.

I will of course always check my tank before I leave the shop. On the other hand, if I have to ask the shop to take care of a short fill, I would expect the shop people to be super embarrassed about it. I know I would be.

 

[CT-Rich]

I will of course always check my tank before I leave the shop. On the other hand, if I have to ask the shop to take care of a short fill, I would expect the shop people to be super embarrassed about it. I know I would be.

Getting a good fill is more important than a slice of humble pie… The guy filling the tank is not a craft brewer and this is not fine woodworking. I would rather he fix the tank and recognize me as the guy who checks his tanks before leaving.

 

[rob.mwpropane]

I’ve seen that. Leads to overfilling. I say good! I knew there was a reason I liked it

Speaking from experience it probably does. I typically have 3600-3750 once the tank equalizes with the air temp. That’s perfectly fine to me.

If my AL tanks are overfilled I will bleed them down to 3100 or so if I’m not using them right away. My HP steel tanks I have no issue leaving them with 3600-3800.

Any reason why you bleed the Al tanks down to 3100? Is there anything wrong with adding a little extra to an Al tank? I pump mine to 3300 and it cools a little, so 3100 is usually around where it falls. I'm just curious your take?

Thanks!

 

[Bob DBF]

The guy filling the tank is not a craft brewer and this is not fine woodworking.

It is a proffessional service, I expect them to be proffessional. In my case, in a previous post, it was a matter of bringing it to the attention of the manager and giving positive and negative feedback as he trained his staff. In the end, I no longer received short fills, and neither did the others I met and discussed it with.

 

[ATJ]

I've had experience with three different compressors (one of them now at home) and have found that the gauges tend to read high. I can fill a tank to tank to 245 bar according to the gauge on the compressor and put a separate gauge on the tank immediately after the fill and it will read under 235-240bar. It then cools down to around 230bar (which is what I want).

I don't know why they all ready high but they do. I now fill my 232 bar tanks to 245bar and my 300bar tanks to 325bar and I end up with the correct fill every time.