I have recently taken the plunge and bought an Rtech mig 250. I have only just got around to trying it out tonight as I have had to run a 32amp power supply in. The problem is that when I set it up to give it a test drive I seem to be having a gas flow problem. I have used the bottle of co2 off my old SIP 195 (at least half full bottle) but when i strike up I can hear the gas flow and get an initial shield but as I am welding the shield runs out as though the regulator is faulty or the bottle has run out (it isn't as it works fine on the SIP mig) am i missing something or could I have a faulty mig set from Rtech?