Others What Causes a Fill Whip to Keep the Male Foster Fill Valve on an Airgun Open While Attached?

[Ezana4CE]

I have a portable HPA compressor that I will use on rare occasions. Today was one of them. I topped off my GK1 without issue using its fill probe connected to the portable compressor's female foster fitting on the fill whip. I filled, bled, and removed the oil probe without issue. After I affixed the female foster QD fitting to my Bushpig's male foster fill nipple, turned on the compressor and filled the reservoir I encountered an issue. When I went to bleed the line to detach the fill whip form the rifle, the fill whip did not stop bleeding until my rifle's reservoir was empty. The line was obviously under pressure until it bled out. My question is, what causes this?

 

[PasadenaMike]

Ahha I’ve seen it. There is a check valve in the male foster fitting that sometimes doesn’t seal for various reasons. One, it could be the check valve is dry so put a drop of silicone oil on the inlet to the gun and fill your gun normally . Second , when you are done filling release the air quick so the check valve in the fitting shuts quick. If all of these don’t work then it’s time for a new o ring in the male foster fitting which I’m sure AOA can help with.

 

[Ezana4CE]

Ahha I’ve seen it. There is a check valve in the male foster fitting that sometimes doesn’t seal for various reasons. One, it could be the check valve is dry so put a drop of silicone oil on the inlet to the gun and fill your gun normally . Second , when you are done filling release the air quick so the check valve in the fitting shuts quick. If all of these don’t work then it’s time for a new o ring in the male foster fitting which I’m sure AOA can help with.

@PasadenaMike When you had check valve issues, was it a constant problem or did the issue occur intermittently? I had no issues after connecting 3 different SCBA tanks to the rifle after this occurred. I didn't have an issue topping off or removing the fill probe from the gun I topped off just before the Bushpig.

 

[PasadenaMike]

@PasadenaMike When you had check valve issues, was it a constant problem or did the issue occur intermittently? I had no issues after connecting 3 different SCBA tanks to the rifle after this occurred. I didn't have an issue topping off or removing the fill probe from the gun I topped off just before the Bushpig.

Then it’s probably something with the compressor. My issue was the little tank I was filling with didn’t release fast enough. It was on a marauder pistol

 

[Madhatter]

Your hose is probably to small a diameter to bleed the air out fast enough to seal the check valve. I have a fill station with a very small diameter hose that does that with my Sumatra. My other fill station releases the pressure quick enough for the valve to seal. 1 time I pumped up my Sumatra with a hand pump about a 1000 psi just to see if I could do it. Well I did it but when I went to vent the very small hose all of the pressure leaked out before I was able to finally disconnect the foster fitting. I don't have that problem with one of my fill stations with a larger hose.

 

[Ezana4CE]

Your hose is probably to small a diameter to bleed the air out fast enough to seal the check valve. I have a fill station with a very small diameter hose that does that with my Sumatra. My other fill station releases the pressure quick enough for the valve to seal. 1 time I pumped up my Sumatra with a hand pump about a 1000 psi just to see if I could do it. Well I did it but when I went to vent the very small hose all of the pressure leaked out before I was able to finally disconnect the foster fitting. I don't have that problem with one of my fill stations with a larger hose.

Interesting