Miller 252 Can't turn heat down

[Buckmaster1967]

Hey guys,
Was welding hard wire .35 wire and mixed gas with me Miller 252 Mig welder . Purchased it new couple years ago. Never had a second of trouble with it. Was welding 22ga steel at 15 heat and 88 speed. Been welding about 30 minutes and it started blowing the metal out. Like I had it setting on 24 heat for 1/2" metal. I checked the settings, changed the tip. Need a reset o the machine. Unplugged , plugged back on. Same results, Can't turn the heat now on the gun. No help in troubleshooting guild. Anyone seen this?

[cuttinparts]

That's very odd, never heard of that happening. Maybe its a variable resistor on the other side of the adjustment dial and has gone bad. Could open it up and have a look. If its a variable resistor type you could check with a multimeter if the resistance changes when you turn the dial.

[SegoMan DeSigns]

Try a system reset, my 350P gets out of whack on occasions and requires it:

Pg 30 of the book / page 34 of the pdf doc

https://www.millerwelds.com/files/owner ... 3R_MIL.pdf

[cuttinparts]

Great tip SegoMan, I had no idea!

[dtdetail]

Hi,

The root cause of the problem sounds like a feeding issue.
In my experience power sources don't fail like this, they'll just stop working.

Check your liner, blow it out if you want.
Check your drive roll tension, too loose will cause lack of wire if you torch is all coiled up laying on the ground. Too tight, the motor wont push hard enough (seen robots stay down for way too long because people crank down feeder tension thinking it cant hurt anything).

last but not least just put a new tip on. just do it.

When there's not enough wire, the power source (depending on how smart it is of course) will think it needs to crank up power to shorten it's arc back to normal.

Hope this helps.

[Lee0110]

Check the wire feed: Make sure that the wire feed rollers are clean and free from debris. Also, check the wire feed tension to ensure that it is set properly for the wire diameter you are using.

Check the gas flow: Make sure that the gas regulator is set properly and that there are no leaks in the gas line. You can also try adjusting the gas flow rate to see if that helps.

Check the ground clamp: Make sure that the ground clamp is securely attached to the workpiece and that it is clean and free from rust or debris.

Check for wire feed blockage: Sometimes, the wire can get stuck in the gun liner or the contact tip, causing the wire feed to stop. Try removing the wire and inspecting the gun liner and contact tip for any blockages or damage.

[rock4xfab]

As the material warms up while running the stinger the weld can blow through easier because it is pre heating up ( move faster)

[2strokeforever]

Miller is famous for having the hall sensor fry and output full amps.
Very common on the syncrowave tig.

The ones that seem to fry are usually blue, and LEM brand.
You can get them off of digikey for cheaper than miller.

I am not sure if your welder uses that sensor, but if it does it's likely the issue.

[2strokeforever]

This is what it looks like and if your machine uses one it will have the full weld current run thru the hole in the center, shouldn't be hard to find.

has400-s--500x500.webp

[weldguy]

Great info, I had no idea. Thanks and hopefully it fixes the OP's issue

[2strokeforever]

If you download the hall sensor datasheet you can feed 5v to it and run current thru it and see if it is outputting a voltage that changes with current.
A 400 amp sensor should output 5v at 400a, 0v at 0a