Pump vs gun gauge.

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muradtexas

Member
Dec 17, 2023
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AZ
When I pump my gun (Uragan 2), both gauges seem to be in sync.
However, an odd thing happens when I start pumping. First few pumps, the pressure in the hose starts building up. Then, it stops and starts moving incrementally, I assume that's when the tank is starting to get filled. But that happens at a much lower pressure than the tank gauge is indicating. For example, I stop shooting my gun when it drops just below 200 BAR. When I start pumping, first few strokes, the gauge needle advances rapidly. Then, at about 150 BAR, it stops and start moving very slow. Makes me wonder if my tank has 150 or 190 BAR in it.
Any idea what's happening and why?

Also, my pump has fine dust residue the same color as filter material on the bleed valve. Is that an issue?
 
IMO, none of the button gauges are worth a damn. They’re variable as all get out. BUT, we have to live with that because the rifles just don’t have the room for a quality accurate gauge. Even the digitals are questionable from my reading. Even the 2” gauges aren’t the most accurate either.
I fill my gun using the 2” gauge on my SCBA and then look at what the gauge on my gun says. YMMV.
 
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My guess at what's happening... The gauge on the pump advances quickly as the fill whip fills with air, then the pressure in the pump has to overcome the air holding the fill valve closed. This is probably when you see it slow down. Once it overcomes that pressure and the valve opens you are at or able the pressure in the tank. The remainder of the fill is slower because you have to fill a larger area to top of the guns air cylinder. But, as previously mentions, this is just a guess!
 
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FLgunner said:
My guess at what's happening... The gauge on the pump advances quickly as the fill whip fills with air, then the pressure in the pump has to overcome the air holding the fill valve closed. This is probably when you see it slow down. Once it overcomes that pressure and the valve opens you are at or able the pressure in the tank. The remainder of the fill is slower because you have to fill a larger area to top of the guns air cylinder. But, as previously mentions, this is just a guess!
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Yeah, that's what I figure is happening. The discrepancy is that the gun gauge says 190 BAR, but the pump gauge starts filling slowly at about 150 BAR. If at 150 BAR it starts filling in the tank, then the tank should be at 150 BAR. That's what I'm wondering about.
 
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Gerry52 said:
I've never had/used a pump but any kind of "dust residue" probably should not be there. If it's going in the line, it's going in your gun. If in your gun I would think there'd be a build-up on internal workings.
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The odd thing is that the fill probe doesn't have the residue, I'm wondering if it somehow gets blown out, but not in. Either way, I ordered an inline filter. Until I can afford a compressor, I can keep pumping.
 
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I trust the gauge I think is the best quality. Between my inexpensive hand pump and the gauges of my guns I would trust the gun gauge. But when I fill my gun from my bottle through the fillset with a large gauge I trust the fillset gauge. The gauge on my YH doesn't even work. I didn't use it when it did, I just trust the fillset gauge.

The other thing to remember is the air will heat up when you are pumping so it is normal for the pressure to go down a little as the air cools. I normally let the YH fill the bottle to 300 bar but if I look at it after it sets for a few minutes the gauge will not be at 300 bar any more. Maybe 290 bar. Normally the next time I look at the gauge is filling a gun so it is decreasing too.
 
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