RT effect question

[Automag ReTro]

So today I got out and had a full day of playing at a new field. Overall awesome experience. The gun was consistent and after a little Lvl 10 adjusting there were no leaks of any kind. The one thing that seemed odd though was that it only wanted to RT from like 4200psi down into the high 2k's. Just a week ago I had the same exact setup: same tank regulator putting out about 1000psi, the same bolt spring, everything the exact same, and it was RTing like a beast until about 1k air. What would make somethng like that change?

For reference purpose:

RT Pro
X-valve
RT on/off
Short Lvl 10 spring
3 shims
1000psi output

P.S.

On a sidenote, as I was typing this I heard a big burst of continuous air coming from our gear room. I go in there and my tank is dumping air out of the internal pressure gauge and has blown the little plastic cover into oblivion. In the big scheme of things it was a slow leak; I unhooked my Macro line and screwed it into the ASA so it would finish up quicker. What would cause that sudden eruption?

[Frizzle Fry]

it was RTing like a beast until about 1k air. What would make somethng like that change?

Is your tank reg putting out about 1k psi?

[Automag ReTro]

Yeah, starts out around 1k, then drops to about 850 as the tank gets low. Pretty sure the output pressure was the same today as it was when I first got the regulator and tried it out on the gun. What thinks ye?

[Frizzle Fry]

Well, your tank puts out 1000 psi from the reg when the bottle is full (4.5k), but as the internal pressure drops so will the output (more so as the tank pressure approaches the output pressure). If the internal pressure is below the set output pressure, it's going to put out a lower pressure than what it's set for. It's less noticeable and less of a problem with the more common low output tank, for obvious reasons. Just keep in mind that the gauge on your tank reg is fairly inaccurate - they all are.

[Automag ReTro]

Yeah, I understand that. But how do you explain that it was RTing extremely well, for long bursts at the field last week that only fills to 3k, and this weekend, would only RT, for short bursts, from 4.5k down to 3k or so?

[Ando]

Your reg is probably screwed up bro. The output pressure should always be consistent to the preset PSI but as Frizz pointed out. If you have it preset to 1k and the internal pressure reaches and goes below 1k. Your not going to keep getting 1k out the reg. The output pressure is going to follow the pressure in the tank.

My best advice is to tear down your tank reg. Replace all the seals and go from there.


EDIT:
I just finished reading your bottom part of your post.

What type of reg do you have?

[Automag ReTro]

The reg I use is one by a company called Rehvac. It's pretty obscure and not much info is out there on them, but the pro shop at the field I play has them pretty much for mag users. The owner of the field uses one on his gun with apparently no issues. I'm gonna try to call him tomorrow on my lunch break or something and ask some questions.

As far as it being bad, I'm not gonna rule that out, but it is brand new and has only had about 2 cases through it. What about the gauge blowing out, what would cause that?

[Frizzle Fry]

As far as it being bad, I'm not gonna rule that out, but it is brand new and has only had about 2 cases through it. What about the gauge blowing out, what would cause that?

Well there's a break-in period on the regulator but with two cases through it that probably wouldn't be the issue. If the gauge blew (they're fragile in addition to inaccurate) it was probably over-pressurized which could also damage the regulator itself. Rehvac makes good stuff so I would tend to doubt that it's a QC issue, probably user-error on the part of the field staff at the field station.

[Tunaman]

I would not run Macro at 1000 psi. Something is gonna blow.

[Frizzle Fry]

I would not run Macro at 1000 psi. Something is gonna blow.

Agreed. Even the stuff that's rated higher is a risk, and not every fitting will keep up with it. If you're concerned about braided steel or hard line looking funky you can get heatshrink tubing in just about any color and plenty of patterns and designs. Much safer and frankly more durable, as Tuna pointed out.

[Spider-TW]

So today I got out and had a full day of playing at a new field. Overall awesome experience. The gun was consistent and after a little Lvl 10 adjusting there were no leaks of any kind. The one thing that seemed odd though was that it only wanted to RT from like 4200psi down into the high 2k's. Just a week ago I had the same exact setup: same tank regulator putting out about 1000psi, the same bolt spring, everything the exact same, and it was RTing like a beast until about 1k air. What would make somethng like that change?


The temperature could possibly make a difference.

Or maybe your gauge was already on its way out.

[Frizzle Fry]

Or maybe your gauge was already on its way out.

Good call... The output is 1k psi, the gauge was blown (not completely out as is often the case) and it was at about 1k pressure but the gauge appeared to be 1.5k-2.5k. Bleed your tank completely - what does it read? I'd bet it's over 750psi.

[Automag ReTro]

I'm kinda confused where you guys are going with this whole gauge thing? The output gauge appears to be fine, the internal pressure guage is the one that blew up and emptied the tank.

[Automag ReTro]

I will say that the temperature may have had something to do with it. When everything was working 100% the temps were around 70, this past weekend it was about 55ish.

[Frizzle Fry]

I'm kinda confused where you guys are going with this whole gauge thing? The output gauge appears to be fine, the internal pressure guage is the one that blew up and emptied the tank.

...I'm confused.

The gauge on the tank regulator is blown, yes? That is, the regulator threaded into the tank which threads into the ASA. If that was blown, it would read over 0psi even when it's empty. It wouldn't effect the emptying of the tank however, though the high pressure that killed it the gauge could have blown a burst disc and caused the tank to decompress.


My guess from this description is this sort of chain of events -

1) Tanks is bought set to 1000psi output, and filled/used. Under 1k of remaining pressure = under 1k output = difficult to R/T. Normal.

2) Field flash-overfills tank, slightly offsetting the gauge, and later it appears to be at just under 2000psi when it is in fact under 1000psi, making it difficult to R/T when (it seems) it has enough internal pressure to put out the full output pressure of 1000psi.

3) Field overfills tank again (they're not good at this, they did it the first time too) and when they thought they'd overfilled it a little, say 3.5k to 4k it's actually more like 4.5k to 5k psi because the gauge isn't accurate anymore. Now it says 3000psi when it's in fact under 1000psi and the lack of R/T effect becomes more and more pronounced.

4) Field overfills again (hell they could be doing it right, the gauge is loopy) and it blows a burst disc.


Long story short - you're field needs a refresher course in fill-station operation. *edit* oh and you need a new gauge and burst disc.

[Automag ReTro]

Yes, the gauge on the tank regulator. It's adjustable, so it has two gauges, the output gauge and the 0-5000psi gauge. When I heard the tank venting I checked it out and all the air was coming out the center of the gauge, it started to get ice on it.

I guess if the gauge was bad to begin with they could have over-filled it and then your "theory" would be pretty legit. I never saw the gauge read any higher than 4200, but again, if the gauge was bad who knows what it was really at.

You say I need a new burst disk, but I don't think that's the case. The disk isn't in or behind the gauge is it? It's the little bold, nut, screw thingy sticking out the side of the reg, along with the two gauges and the fill nipple right? I just asked my roommate and he verified that all the air releasing from the tank was coming right out the middle of the busted gauge, until I screwed it into my ASA.

[saintnoir]

sounds like an overfill to me i dropped using my angel air regulators because no matter how simply i explained to give it a slow fill (went so far as letting anyone else who needed air ahead of me)they would dump air and blow my valve.
if the tank gauge was a bit sticky and it got a few 100-200 psi overfills it would wear out the burst disk