Gas flow problem on a Millermatic 350P

[Danl]

I would be very interested in the results of this problem.

Regards, Danl

[FusionKing]

Well let us know, whatever it turns out to be.

[JEFFAB]

Good ideas...
The regulator and hose that are on it now I swapped off a 252 that has been running fine for years. I'm wondering if something like what you are talking about isn't happening with the hose inside the machine between the gas solenoid and the drive rolls. Maybe it has debris in it or is freezing up. Problem is you have to take a bunch of stuff apart to get to the drive roll end of this hose

[H80N]

MIG gas flow rates can vary from 25 CFH for 1/16 inch Aluminum to 85 CFH for 3/4 inch Aluminum... suggested

See page 16 & 17 of the Maxal/Hobart Guide

http://www.maxal.com/files/QuickSiteImages/Maxal_Guide_for_Aluminum_Wldg_9-12_doc.pdf

BTW this guide is worth downloading and reading...

[FusionKing]

Make sure it is the high flow regulator also.....I have found mig can require much more capacity than say tig. I always buy the good stuff anymore or it acts exactly as you describe. It'll blow great until the line empties and then it'll flow just enuff to drive you nuts.
I believe it is supposed to be like 50 something of whatever unit they measure in.
My 350P came with a great big Smith regulator.
You would think flow is flow, but not necessarily in my experience. Esp. on aluminum

[gnforge]

Gas flow problem on a Millermatic 350P

Had similar issue with mine after a year or so.
As Cruizer said !! I traced it down to debris where hose goes into Michine.
Working fine since.
Also hv seen faulty hose as in brake caliper & fuel lines, inner liner blocks or restricts flow. May try another hose just to eliminate possible issues. Just some thoughts

[cruizer]

Remove the gas line from the machine, there is a screen there, Remove the crap from it, like Teflon tape and such

[ja baudin]

Just guessing, bad regulator or its freezing up after extended use?

[JEFFAB]

We have a millermatic 350P that we bought brand new about 4 months ago. We have been having an issue where the gas flow becomes intermittent when we are using it for a while and really getting the machine hot. It has been back to the local dealer twice for repairs and it is about to go back again. I figured I'd post on here and see if anyone has any ideas since they don't seem to be having much luck with it at the welding supply.

What will happen is it will weld fine for a period of time (usually 15-30 minutes or so) and then when you are about an inch or so into a bead the gas flow will drop and the weld will completely bug hole out. If you stop and pull the trigger it will blow gas and it will blow gas for an inch or so of bead and then it will bug hole out again. It will weld like this until it cools down

The first time it went in for repair they replaced the gas solenoid.

After we got it back it seemed like it did better for a while but when the guys got running it hard one day the problem came back. I took the side panel off where the gas solenoid is and when it was having the problem the gas solenoid was over 200 degrees F. I also seemed to help leaving the cover off.

The next time a sent it back telling the tech about how hot the solenoid was getting they replaced the solenoid and a temperature sensor.

Now that we have it back again it is still having the same issue.

This is our first 350P and at this point I'm really wishing we'd bought another 252. This machine is being run right along side other millermatics (250s - 252s) and they never have issues. The guys love the 350p when it works but no one will use it because when it looses gas flow they end up having to do a bunch of grinding.

Does anyone have any ideas? Is there something else that could be causing the gas solenoid to overheat? Some other issue that could cause the gas flow to drop during a weld? At one point I wondered if it had dirt in the gas line from when it was built so I put a flow meter gauge on it and I can never see the flow gauge drop. We've tried different wire, gas, gas line, different gun all to no avail.