Miller 22a not purging

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Hope some one can help me out here. I've got a Miller 22a wire feeder that will purge gas when I hit the purge switch on the machine, but won't when I pull the trigger on the gun.  Bought this setup pm ebay a few months ago and both the gun and feeder were brand new.  The gun is the Bernard Q300.  Any help would be appreciated, thanks!
Reply:Check that the gun is installed all the way in the feeder. I see this all the time at the tech school. The kids like to pull the gun out just far enough that it blocks the gas ports. Then the next kid thinks he's out of gas and  has to drag in a new cylinder to change it out, only to find after all that work, he still doesn't have gas..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Wish that was it... gas solenoid activates when the purge switch is hit but doesn't when the trigger is pulled... very weird.
Reply:Does it feed wire when the trigger is depressed, but doesn't flow shielding gas? Or does it not do anything when the trigger is depressed?If it does feed wire but not flow gas that is certainly a bit odd. Although there is a possibility that the purge button is a direct feed to the gas solenoid and the trigger solenoid may be tied to another relay that provides both wire feed and gas solenoid activation when it is engaged. Another individual on the forum here could likely give you a pretty concise rundown on what could be going on with your feeder, he goes by 7A749 and is awesome with his knowledge and help. Good luck and best regards, Allanaevald
Reply:Hey Allan, Yeah it feeds wire fine, I've ran about 20 lbs of flux through it with no issues.  I was wanting do do a little exhaust work with it so I loaded up the solid wire and noticed no gas coming out of the nozzle.  It is a very strange problem indeed.  I'll send 7A749 a PM and see what he thinks.  Thanks!
Reply:If you can feed wire and the welder output turns on. You can weld with flux-core wire and the valve will open in purge and gas does come out miggun nozzle. But no gas when miggun trigger.Then the problem is at the back of the purge switch. Take the cover off the feeder. look at the back of the inch/purge switch. I think you will find a pair of wires connected together that have come off the switch. wires numbered 35 and 38. find the side of the switch with wire  36 and 1.36 is the center connection,  35/38 and #1 are top and bottom.wires 31 and 32 are on the other side. DO NOT GET THE WIRES mixed up or you will kill the motor pcb. There should be a diagram pasted inside the cover.The inch/purge switch looks like a standard DPDT (on) off (on) , but it is not. It has jumpers inside the switch body. As long as 31/32 are on one side and the rest are on the other side.It won't damage the pcb, but may not work right until they are put in the right place.31 and 36 connect to the two center connections. Good luck and be careful,If no diagram in side the case, take the serial number to Miller's web site and down load the owner's manual.
Reply:Thanks ccawgc.  So here's a pic of the switch as it is now.  I first swapped locations with 1A/B and 35/38, nothing changed so I put them back.  Then I swapped 32 and 31 around, still no change.  With those still flipped I then changed 1A/B and 35/38 again with still no results.  In all the configurations I tried the purge/inch switch still performed it's duties fine but miggun switch would still only feed wire.  It is still under warranty so I'm gonna take it in and have them look at it, Miller tech support and the local service rep both seem to think it's the board.  Hopefully this is a rare occurrence and these boards aren't prone to failure.
Reply:Just picked it up from the service tech.  Worked perfectly fine for them.  Got it home hooked it back up to the thermal arc and it still doesn't work.  It's gotta be the 14pin connection at the thermal arc, maybe it was rewired for a Lincoln before I got a hold of it?  Is there a way to test this connection with a volt meter or way way to visually inspect the wires to make sure they're all going to the right locations.  The miller 14pin has plugs at A, B, and G.  What a headache!
Reply:Just an update here. Finally figured out the issue.  It was all in the Thermal Arc this whole time.  When I bought it 10 years ago or so I plugged it in, it worked so I just kept using it as it was.  Come to find out the AC plug was wired wrong.  White wire was being used for common and red was being used for hot.  When being used for single phase application the red wire is not used and the white wire becomes a hot wire.  Rearranged all the wires and it seems to be working fine now.  Kinda surprised it never fried any circuit boards... and I suppose all this time I was just getting 120v... not sure about that theory.    Anyway mystery solved!