Mig Solenoid Gas Valve Sticking Open

I just switched from C25 mixed gas to straight CO2 for the first time today. After a few welds the solenoid gas valve starts to stick in the open position so gas still flows when you let up on the trigger.

The regulator was also covered in condensation, so I theorize that the solenoid valve is icing up.

Has anyone else had this happen? What is the solution to this problem?

I know lots of shops run straight CO2, so I must be doing something wrong.

Machine is a Millermatic 252

quick way is to position a trouble light so the bulb heat is going on the regulator. If that isn't enough heat then go to a halogen.

Sounds like your flow rate is way-way too high.

I run 100% CO2 on a couple of welders, and don't have the regulator icing problem, nor going downstream to the solenoid.

The larger users use a regulator with a heater built in, look for a 6" long grounded cord hanging out of it.

Co2 Heated Flow Meter/Flow Gauge - 115V U.S. Style [PX-RFG-32-H] - $184.3 : Arc-Zone.com, The Welding Accessory Experts

cant see the savings in cost being worth the increased spatter, and general lowering of consistent weld quality, myself- but then I tig 90% of the work in my shop because I hate cleaning up dingleberries.

I had the flow rate set at 25 cfm at the beggining and when I checked it when I was done the gauge read 35 cfm. I don't know why it changed (l may have bumped the adjustment handle). Maybe the 35 cfm was enough to cause the problem.

I tried the CO2 because I only have one C25 bottle and I ran out. The CO2 is my backup.

I know that everyone says the C25 is supposed to result in better welds with less spatter, but I found exactly the opposite to be the case. The CO2 welds look just as good as the C25 with less spatter and less smoke. The C25 mix is also twice as expensive.

The only problem with the CO2 is the gas valve sticking.

I will try a lower flow rate. The other thing that occurred to me is I have the hose coiled up above the inlet port on the welder. I don't know if that loop is allowing liquid CO2 to accumulate.

The last time I ran CO2 on a Mig was back in about 1994 using a smaller welder. I can remember the regulator sweating, but never remember having solenoid valve problems.