The dwell pot on your LED controls the time that the solenoid switches on. The longer it stays on, the more gas is used, and it will be more tolerant of fragile paint. The shorter time it's on, you will use less gas.
There is a "correct" setting for dwell, and here is what is reccomended.
To ensure the dwell time is set correctly, first set the gun at a constant velocity, e.g. 300fps.
Then turn the dwell pot (the lower one in the grip frame) all the way anti-clockwise.
The gun is then at it's least efficient setting. Gradually turn the pot clockwise, while firing the gun over a chronograph, you will hear the noise signature of the gun change.
When the chrono reading starts to drop, turn the pot anti-clockwise a few degrees and ensure your chrono reading is consistent, the angel is now at it's most efficient setting.
If you turn the valve dwell down too much, you will starve the valve of gas to propel the ball at the specified velocity. If the dwell is set too high, the gun will sound very loud and inefficient.
Hope this helps, there is more info like this at
www.wdp-paintball.co.uk
Tom.