Millermatic 252 questions

[weldme]

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I recently bought a Millermatic 252 welder.

I've used the welder maybe a dozen times for welding in a bodyshop. I was welding in a rear floor pan and stopped to take lunch. When I returned and started welding again I didn't have any gas flow. I checked all the obvious things such as a kinked line or clogged gun tip. Looking at the regulator mounted on the gas bottle I noticed that the the gauge was pegged to the maximum where I usually set it at 30. I tried to make adjustments but it wouldn't change. I then took a regulator off of another welder in the shop and the gas did start to flow again. I think I have a faulty regulator. With that being said, will this stop the gas solenoid from turning on? The reason I ask is I want to make sure I don't have another (or different) problem as well.

Thanks...
weldme

[Black Wolf]

Regulators are mechanical devices that are not part of your MM252 so it will not have an effect on your machine. The only thing that will affect your gas solenoid, is not receiving a signal that the trigger is engaged as it is electrical. The amount of flow trying to pass through the regulator, or the amount of pressure pushing on the backside of the solenoid while the trigger is "off" will have no effect.

Later,
Jason

On edit: Remember that to when changing the settings on regulators, you must evacuate the builtup pressure on the regulated (or downstream) side of the regualtor, in order for the gauge to show a drop in regulated pressure. Doesn't matter if it is Oxy/Fuel gas torches, shielding gas, air supply to Plasma cutters or Pneumatc tools.....All regulators work the same.

[weldme]

Black Wolf, thanks.

I thought maybe the excessive pressure placed on the gas solenoid valve may have stopped it from functioning. I see now this wasn't the case.

So this raises another issue.

Why wasn't the gas solenoid turning on? I don't think the machine was overheating, although it was probably the most the welder has been run consistently at one time. Welding the thin autobody sheet metal the machine was probably set somewhere near 16 and 130-ish on the wire speed. I can say I have NEVER heard the cooling fan come on, but have noticed the front/top of the machine getting pretty hot...

Any ideas? Is there ways I can check the cooling fans operation?

Needless to say I don't want the machine overheating, nor do I want the gas solenoid to stop working while in the middle of a job.

Thanks for your help. It's greatly appreciated...

Weldme

[SundownIII]

Weldme,

The first question I would ask you is why are you running your gas flow at 30CFH. Seems extremely high. For the type work you're doing I would suspect something in the 15-20 CFH range would be more appropriate.

Additionally, as Black Wolf has already indicated, you need to adjust your gas flow with the gun trigger engaged (solonoid open). Simply pull the trigger and adjust gas flow accordingly. (Make sure the wire doesn't contact the workpiece)

The high readings you're seeing on your gauge could be because the flow rates were improperly adjusted. The pressure/flow rate will always appear higher when the gas solonoid is closed. The gauge is actually a flowmeter vs a pressure gauge. It's only accurate when gas is actually flowing.

I don't have (nor have I used a MM252) but I do have a MM251. At the settings you mentioned, I can assure you that you are nowhere near the duty cycle of that machine. At those settings the fan (Fan On Demand) will probably never come on. Don't worry about it. At those settings (and even much higher) you have a 100% duty cycle.

Just my .02

[weldme]

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We run the gas up near 30 because of the ceiling fans in the shop, (and we don't pay for the gas, the shop does.). We are also one of the few shops left that "pride ourselves" on our work. So weld quality as well as appearance is still extremely important to us. I can't tell you how many bodyshop repair jobs I've seen that the car should be taken off the road because of poor or shoty welds at best. They surely wouldn't take a hit of like or equal force with out coming apart. I'm sure the car owners can hear the welds "snapping" apart as there riding down the road. (not funny when you think about it). BUT, I will look into lowering the flow. You may have a good/valid point there.

We have three Millermatic 185's in the shop besides my Millermatic 252. I have never seen the flowmeter max out when the welder is not in use using the other welders. Thats what raised the question in the first place. I suppose it was just an odd coincidence that the welders gas solenoid started working again when the gas regulator was replaced with another. I haven't used the welder since this posting. I should be using it again today though. I'll let everyone here know if I continue to have problems.

I didn't think I was overheating the 252, I just wanted another opinion to make sure. With the new "fan on demand" cooling system I wasn't sure when it was suppose to start coming "on". I hate learning the hard way, and I paid for this welder myself...The fan on demand seems to be a good thing, especially in the bodyshop environment where body filler dust is flying around all the time.

I really appreciate you guys input. Puts some worries to rest.
Weldme

[SundownIII]

Weldme,

No problem. Just suggestions.

The reason I mentioned the gas flow (30CFH) was because sometimes excess flow can be as disruptive as lack of flow. Depending on the situation, too much flow can cause turbulance and bring in outside air to the weld.

On the issue of gauges, I suspect you did in fact have a bad flowmeter. The Smith flowmeter that comes with the MM251/252 is not what I consider to be of "premier" quality. A "floating ball" flowmeter is much more accurate and is what I use on the Syncrowave for tig.

Good to hear that there are shops out there that still take "pride of workmanship". My dad ran a body shop for over forty years. I grew up in the shop. My uncle, who was a "hardhat diver/welder" in the Navy in WWII, was the one who initially taught me to weld when I was about 6 yrs old. With the amount of "leading" (no bondo then) I did, I guess I'm lucky to be here today. Same could be said for my dad, who's 84 now and still going strong. Those were the days when bodymen were "metal sculptors" not parts changes, which seems to to be today's norm.

Keep up the good work.