New 250EX owner, a few problems

[Adambomb]

Hello fellow welders, I am happy to say I'm the new owner of a power tig 250ex as of yesterday. Once wired, the machine powered right up, and I was anxious to try it out. I am also new to tig welding, so go easy on me guys.

So the issues I have found so far are (1) the HF start does not work and (2) after completing a bead and letting off the pedal, the arc continues to flow. The only way to stop is to pull the torch away from the work. I have a feeling the two issues are interconnected, but I don't have enough experience to figure it out. Any insight is appreciated. I have tried resetting the HF points gap anywhere from .025 to .060 and still no joy. I have also put in an email and a couple messages to tech support, so hopefully Mike will get a chance to get back to me soon.

[performance]

check this without the foot pedal engaged. Try the torch switch only.

[Adambomb]

I had tried both the foot pedal and the torch switch on 2T and 4T to no avail. So after you suggestion Mark, I messed around with it again, but this time I held the button on longer (10 seconds or so) and the HF kicked in. I dialed down the preflow to 0 and now the HF works just fine in torchand pedal modes. The arc remaining active after lifting the pedal or releasing the torch switch is still present, but it does go out by itself after 6-7 seconds. Perhaps this is a cool down feature/program?

[Wrenchtamer]

does the arc seem to be ramping down before it goes out? Just a thought but try setting weld parameters end amps and downslope to zero? I have a 256, which they say is basically a 250ex minus a couple of features plus plasma, and if preflow is set too high the hf can take a long tme to initiate. Postflow does not seem to affect arc time but downslope does. Just a thought.

[Rugar]

Try setting the preflow, postflow, upslope, and downslope all to 0, and the start amps and end amps to 100% as a test to see if it stops and starts the arc when you release the pedal or switch.

If that all works, then go to this link for a series of videos on what each of those functions does.
http://www.everlastgenerators.com/video-library.php

[sschefer]

On the pre-flow issue. Set it to about 1 second and post flow to 1 sec per thou of metal thickness. I use about 10 seconds as a default.

Just before you start to weld, tap the pedal and that will give you about 11 seconds of flow to purge the hose. You can start to weld as soon as the initial purge rush is done.

On HF start, I found that even after setting my contacts, the first start need to be a lift off start. After that HF start worked fine but I frequently touch the tungsten to material briefly before starting to correct polarity. This is a pretty common practice on all TIG machines. I did it on my Lincoln and the Dynasty I borrowed.

Technically, the upslope and the down slope should be turned off when using the pedal. The pedal is used to control it.

The 4T position is mainly for a mounted torch but it can come in handy when welding weird out of position stuff where you need a little extra help. Normally you'll use the 2T position.

Theres a lot of knobs on the machine but once you realize when to use them an when not to, your welding will improve. TIG takes practice and every machine takes time to get used to.

I've only had about an hour on my 250EX and I really like it. It took about 30 minutes to get a feeling for what all the knobs do and I'll probably never try all the possibilities.

Hope that helps.

[performance]

On the preflow, no such long time is needed. Units without adjustable preflow are typically preset to less than .5 second. Post flow is more important. Preflow is mainly needed to give enough time for the gas to flood the immediate weld area and to stabilize the flow. 11 seconds of preflow is just wasteful and not that much is required. Argon is heavy and doesn't exit the hose that much when not in use. As soon as the burst of gas flowing is heard, it is purged.

It does sound as if you have the down slope engaged too long. Also I'd check to make sure you are operating the foot pedal in 2T not 4T. Down slope/post flow can take time to stop the current. If you are operating the unit in 4T, I suspect that you aren't operating the cycle correctly. This would be a definite sign if you are holding the switch down in 4T as well.

[Adambomb]

does the arc seem to be ramping down before it goes out? Just a thought but try setting weld parameters end amps and downslope to zero? I have a 256, which they say is basically a 250ex minus a couple of features plus plasma, and if preflow is set too high the hf can take a long tme to initiate. Postflow does not seem to affect arc time but downslope does. Just a thought.

The arc does ramp down, so I'm sure it has something to do with the down slope adjustment. I'll turn it down to 0 and see what happens when I get home this afternoon. Thanks for the suggestions guys, this is just a minor stumbling block and mostly due to my lack of experience (except for the initial HF point gap setting). I'll post my results later today

[Adambomb]

I tried setting the upslope and downslope to zero. The first couple arcs I initiated still did not shut off like before, then with no other input things started working correctly, with the arc stopping as soon as the pedal was released. I'll keep an eye on it....hopefully the phenomenon will not return. After a few messages over the last couple days, I was finally able to talk to Ray, a west coast tech support specialist who informed me the HF gap is supposed to .040" As delivered my machine was .080", and right now I have it around .060", so I need to open it back up and reset the points. Is it normal to have to open up and repair a new machine? Being new to tig welders I can say I don't know of its normal or not. I am a little dissapointed at having to correct this small but important discrepancy, but Alex did say he would make it right so I can't complain too much. On learning to tig weld....all I can say is I am GLAD I learned oxy/acet welding in H.S. I'm rusty, but it has given me a big head start.

[Stelfabulous]

I use a wooden ruler to set my gap. Watch for the HF sparks through the front grill. Go up through there, no need to take your machine apart.

[performance]

Adam,
The cog on your foot pedal may be a little loose or the pedal isn't resetting the on switch correctly. You may need to open it up and check the pedal function. Something like this is either going to work or its not if its a electronic issue. I am thinking its a mechanical issue.

[Adambomb]

I'll be sure to check the foot pedal if that issue returns, thanks Mark. A new issue popped up today. I was practicing on aluminum Thursday and everything was going well. I turned off the welder and wrapped everything up. This afternoon I turned it on and started back to practicing on aluminum......except now the power output is exponentially higher????? I turned the power rheostat down to the minimum and the LCD is still showing 26 amps, and as soon as i strike an arc it blows right through anything. I tried it on AC and DC, aluminum and steel, same effect. I also turned up the amp rheostat, and it's maxing out at 276. Wierd......anyone have any idea what I could have done to make this happen? Gas (pure argon) has 1800 psi in the tank, and I tried it with several different tungsten (2% thoriated) in 1/16" and 3/32".

[performance]

There is an adjustment on the top board for this, but I can't figure out how the resistor setting was changed unless it was somehow turned in the point setting process. Other than that, it still sounds like a foot pedal issue...if the cog isn't fully returning or slipping, it will show the minimum amps it returns to.

[Adambomb]

I haven't had the cover off since the machine was welding properly, so I think we can rule out the internal adjustment. It could be the pedal Mark, but if I have the output turned down to the minimum (26 amps), wouldn't that limit the arc output to 26 amps with the pedal floored? I forgot to mention that when I initiate an arc with 1/16" tungsten, it melts the tungsten back almost to the collet and blows a hole in 1/8" aluminum......at 26 amps and the foot pedal barely pressed.......I suppose I'll take the pedal apart. What should I be looking for inside it Mark?

[performance]

There are a couple of things that we probably need to go over and would be faster over the phone. We'd need to get a quick idea of all your settings. Give us a call Monday, or email to let us know when to call. In the mean time, a few things to answer:

Is the unit firmly in 2T?
What is your start current setting?End current?

[Adambomb]

The machine is set in 2T. Start and end current are both set at 0; It was my understanding that the foot pedal takes over the start and end current in 2T. Just for comparison, I unplugged the foot pedal and connected the torch switch. The indicated output amps dropped to 004. I plugged the foot pedal back in (with no other changes) and the indicated amps jumped back up to 26. Based on that observation, I believe your original diagnosis of a malfunctioning foot pedal has signifigant merit.

[Adambomb]

OK, I just did another check with the pedal attatched. Without welding anything, I depressed the pedal and watched the output amps. As soon as the micro switch is triggered, the amps jump from 26 to 280. That would explain why the 1/16" tungsten would shrivel up into the cup like a frightened turtle while blowing through anything the arc touched. I opened up the foot pedal to see what I had to work with. A micro switch and a 47k potentiometer. The potentiometer has a small amount of adjustment. Unfortunately, the lowest starting amps I could get was 21. Even then, as soon as the micro switch is triggered the amps jump to 270. I'll try welding with the torch switch and see if the unit behaves. If it does, that should be enough evidence to isolate the foot pedal as the sole culprit.

[Adambomb]

Welding in 4T with the torch switch works just fine, so it would seam I have a malfunctioning potentiometer, unless Mark or Mike (or anyone) has any other ideas on the culprit.

[performance]

Adam,
It would seem so...or something has slipped on the potentiometer or on its shaft.

[Adambomb]

I may be new to tig welding, but I can say this; welding aluminum sucks without a foot pedal!