Squealing noise when filling s400

[svendogg]

Had my s400 about a week, only shot it twice, needed to refill as it was down to 100bar, connected my bottle, started to fill slowly. At about 150bar, I get a squeaking/ squealing noise, and it won't fill any higher. I had the connector on firmly and rotated 90 degrees to lock it. Held it while filling, loosely so as to not put pressure on it. What am I missing? O ring grease?

[NewPaul]

You will often get a squeal/squeak whilst filling, I do no matter how slowly I fill. Maybe your bottle only has 150bar left in it ?

[StellaArtois Sr]

You will often get a squeal/squeak whilst filling, I do no matter how slowly I fill. Maybe your bottle only has 150bar left in it ?

Oh so that's what that noise is. I thought it was you getting your wallet out.

[NewPaul]

Oh so that's what that noise is. I thought it was you getting your wallet out.

Oi !

[Murphy]

Noises are normal but if it's not hissing out anywhere at 150 then you only have 150 in the bottle.

[angrybear]

Sometimes mine squeals it's just the air flowing through a small hole very fast, a fraction less or fraction more on the valve normally stops it,

If it stops at 150bar then you only have 150bar of air left in the cylinder each time you fill the rifle the pressure in the cylinder drops because you let some air out and all it can do is equalise the pressure in the rifle with the pressure in the cylinder, that's basic physics.

[svendogg]

What would be the best way to test the bottle pressure? I've got the best fittings qd connectors with the stopper in, can I just pressurise the hose? Will that tell me the bottle pressure on the guage? Is that safe?

[rancidtom]

What would be the best way to test the bottle pressure? I've got the best fittings qd connectors with the stopper in, can I just pressurise the hose? Will that tell me the bottle pressure on the guage? Is that safe?

The squeaking is due to the non-return valve in the gun resonating, at some pressures and flow rates. As mentioned above changing the flow rate may stop the squeak.
As regards your bottle pressure if you have a gauge on the bottle it is probably more accurate than the gauge on the gun so always use the bottle gauge for filling and just treat the gun gauge as you might a fuel gauge in a car, know where you should fill up, as these tiny gauges are not exactly the most accurate things on the planet.
If you have a "pressure test plug" simply fit it to the end of your hose and open the bottle valve, the gauge will show the pressure in the bottle. Remember to bleed the hose before attempting to remove the pressure test plug.

[svendogg]

Fitted the test plug, hose pressurises to 200bar no problem. Bottle doesn't need refill then.....

[rancidtom]

OK so perhaps the gauge on the gun is faulty. When you gun gauge shows 150 your bottle gauge shows 200? I have replaced many leaky gauges over the years, I have also replaced "sticky" gauges that seem to be reasonably accurate up to a certain pressure then won't indicate any higher (possibly yours is like this) and gauges that show maybe 0 or even 100Bar when the gun is totally empty.