HW100, still having problems

[Artfull-Bodger]

have you changed the O ring in the regulator inlet valve?

If so replace the old one and try again.

[learningcurve]

I've now replaced the o ring on the inlet valve, and the 12x1 o ring seal, still no joy. Ive tapped the pin on the cylinder, air is coming out ok. I guess the next job is to strip the inlet valve out

[Artfull-Bodger]

If the reg is not filling then the usual culprit is the o-ring that the ball sits on in the inlet valve, but this problem usually appears when you fit a new ring, sometimes the tolerance on the piston pin that opens the valve is such it cannot lift the ball off the ring, try a new o-ring but keep the old one, then re assemble very carefully making sure all the components are nipped up correctly flush with their fitted locations.

[Gunfun]

I'm not as familiar with the hw100 as some people and I would follow their advice first, but a couple of suggestions -

If some air leaks when you remove the air cylinder it suggests some air is entering the first chamber but not getting into the regulator.
1) Inlet Valve (pw240), check the ball bearing and spring are installed in the correct direction.
2) Regulator - Is the regulator adjusting screw turned in enough to push the regulator piston (pw241) against the inlet valve ball bearing, or have your disc springs collapsed/fractured or missing.