PDA

View Full Version : Low Air Fills



AqueousSapien
08-18-2007, 01:49
At what point do you guys think a tank has not been correctly or well filled?

The reason I ask is recently I got tank filled at a local dive place and it was only filled to 2600. I'm still a relatively new diver and I didn't know whether this sort of range is to be expected with air fills and what to do what it. If the tank is this low is it ok to ask the shop to refill it or what? :smiley5:

thesmoothdome
08-18-2007, 01:57
If I'm paying for a fill or a dive, I expect it to be 3000psi or more. Yes, if you're still in the shop, it's definately alright to ask them to top it off.

medic001918
08-18-2007, 06:05
2600 on what kind of tank? I dive low pressure tanks, so 2600 for me is a good fill. If it's a 300 psi tank, I'd definatly ask for more.

Shane

cummings66
08-18-2007, 07:18
On an AL80 tank, common for new divers I would say you got a low fill and I'd want it topped off.

For me I find on HP tanks I get low fills often because they try to fill them likae an AL80 and you just can't do that to a larger steel tank. I've seen them pump 3700 psi in it and say when it cools it'll be fine, wrong. I'd be willing to bet a hot fill in an HP120 would require 4000 psi to end up 3500 psi.

I almost always get a full fill when done with Nitrox, why? Because they have to go slow. That's the key, it takes time to do it right.

TAH 73
08-18-2007, 08:42
Anything less than the tanks capacity I would consider a "low" fill.
And I would have no issue having them top it off. If i paid for a full fill, why would one expect anything less.

ReefHound
08-18-2007, 09:01
Anything below 3000 is a "low fill" and 2700 is an excessively low fill. Whether that "bothers" me depends on the situation. For a local dive at a quarry or pond it is not a big deal, but if I'm paying big bucks for a boat dive then it's a problem.

plot
08-18-2007, 10:18
When it's filled it'll say 3000, soon as the tank cools down after the fill though it'll often times be around 2800 which I consider ok for myself personally. Some shops combat this effect by filling the tanks in water so they're cooling as being filled... then you get a full 3000lb fill. Others fill them, let them cool, then top them off (but that cant be done with a customer waiting on it).

2600 I would consider too low though.

And like reefhound said, if you're on a boat or a professional dive operation on vacation, anything below 3000 is unacceptable. I don't expect much more than 2800 from my LDS though.

NitroWill
08-18-2007, 10:22
Just have patience when getting your tanks filled..People who run in to get them filled and are waiting there anxiously for them being filled are of course at high risk to getting short fills. Whenever I drop tanks off, I give my LDS plenty of time - and just tell them I want a nice slow full fill and they never let me down

DivingsInMyBlood
08-18-2007, 11:02
At what point do you guys think a tank has not been correctly or well filled?

The reason I ask is recently I got tank filled at a local dive place and it was only filled to 2600. I'm still a relatively new diver and I didn't know whether this sort of range is to be expected with air fills and what to do what it. If the tank is this low is it ok to ask the shop to refill it or what? :smiley5:


I would not be happy with that at all, seems like you got short changed on that fill matey. Would this be because their trying to fill the tank too fast?

Jaymeany
08-18-2007, 12:27
thats less then 8 fills before they have shorted you a full tank. if they do it an a regular basis.

ertechsg
08-18-2007, 12:45
If they fill the tank fast it heats up causing the air to expand even more they have to fill it slow. and any tank at -200 is considered full ex...2800 on a 3000 psi tank is considered full

Centerius
08-18-2007, 14:48
Some shops combat this effect by filling the tanks in water so they're cooling as being filled... then you get a full 3000lb fill.

This is a myth that needs to die and if I brought my tanks to a shop that does this, I'd ask for a dry, slow fill. Here is a link that explains more about it:
http://www.fillexpress.com/library/tankfill.pdf

plot
08-18-2007, 15:15
Some shops combat this effect by filling the tanks in water so they're cooling as being filled... then you get a full 3000lb fill.

This is a myth that needs to die and if I brought my tanks to a shop that does this, I'd ask for a dry, slow fill. Here is a link that explains more about it:
http://www.fillexpress.com/library/tankfill.pdf

Guys at the lake do this and i can come home with a 3000lb fill. So what are they doing differently than my shop with the same compressor? And they fill 3 tanks at a time quick and fast to get 20 out the door so we can go back on the boat (don't always use them all though, and come home with 3000lb fills)... they're doing something different, and the tank bath is the only thing I can think of.

kevinj1
08-18-2007, 15:49
I agree, A new diver should get 3000psi or more. I have accepted 2800psi before, and I was uneasy the whole dive.

ReefHound
08-18-2007, 15:51
For anyone who doesn't think a small amount of water cannot dramatically cool a block of aluminum or steel, let me put it in terms everyone can understand. The typical automobile cooling system contains but a few gallons of water running through small passages in your aluminum/steel engine. The engine generates temperatures hot enough to fuse metal and yet this small amount of water keeps it hundreds of degrees cooler than that.

OK, so anyone who still believes a small amount of water has an insignificant cooling effect on a block of metal, go drain your coolant and head for your LDS for a tank fill. I'll bet you don't make it.

Xspect
08-18-2007, 16:09
One of the local springs uses a water tank for fills. We always seems to have a full fill.

AqueousSapien
08-18-2007, 21:12
2600 on what kind of tank? I dive low pressure tanks, so 2600 for me is a good fill. If it's a 300 psi tank, I'd definatly ask for more.

Shane

The tank was an AL80.

BTW, if this is in the wrong section, I am sorry about that. A mod can move if needed.

jerdr1
08-19-2007, 08:36
I dive steel 130s and NEVER get a full fill. I usually just get asked why I need such a big tank..

cummings66
08-19-2007, 08:59
Guys at the lake do this and i can come home with a 3000lb fill. So what are they doing differently than my shop with the same compressor? And they fill 3 tanks at a time quick and fast to get 20 out

Are you talking State Park? What's different is they're filling three tanks which makes it take longer than doing one tank. So, in effect they're filling it slow enough that you get a full fill yet fast enough to do all the tanks.

Wait till you do Project Aware, you'll see many divers get a short fill that day due to fast fills.

Buoyant1
08-19-2007, 09:05
My LDS fills them, then usually tops them off when you pick them up to make sure you have a full fill!

plot
08-19-2007, 09:15
Guys at the lake do this and i can come home with a 3000lb fill. So what are they doing differently than my shop with the same compressor? And they fill 3 tanks at a time quick and fast to get 20 out

Are you talking State Park? What's different is they're filling three tanks which makes it take longer than doing one tank. So, in effect they're filling it slow enough that you get a full fill yet fast enough to do all the tanks.

Wait till you do Project Aware, you'll see many divers get a short fill that day due to fast fills.

lost bridge marina, he does 3 in about 3-4 minutes, my LDS does two at a time alot slower.

cummings66
08-19-2007, 09:48
Now that's fast.

finflippers
08-19-2007, 11:48
One of the shops I usually deal with has a habit of only giving 2700-2800 unless I bring it to their attention before filling and tell them to fill it good then I might walk out with 3000 by the time I hit the site. I think they stop their compressor right on 3000. If they would just fill a little higher and leave the tank hooked up to the compressor for a couple minutes before shutting off the line and bleeding they could improve the fills.