General welding questions that dont fit in TIG, MIG, Stick, or Certification etc.
tfasbind
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Hello all.
I am new to the forum and relatively new to welding. I am retired and recently decided that its time for me to learn some welding. I have taken a couple of welding classes at the local community college and have an Alpha Tig 201XD (for about 1 1/2 yrs) and just bought a Yeswelder Mig 250 Pro.

So, both welders appear to have gas leaks.
Right now I would like to deal with the Alpha Tig.

I turn the machine on, open up the cylinder valve slowly all of the way, then open the gas regulator to @ 20 SCFH.
After about 5 seconds the regulator meter reading drops to zero. If I hit the foot pedal it will go back up to 20 then drop back to zero in @ 5 secs.

I have leak tested (with a solution of windex and water) and there are no leaks from the tank to the welder.
Am I correct in thinking that I have a leak somewhere inside the machine ( I assume the reading on the regulator should not drop)?
cj737
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    Thu Sep 29, 2016 8:59 am

If the machine side of the regulator drops to Zero, that indicates no gas getting to it which would ostensibly make your leak on the valve side of the regulator, not the machine side.

Could also be a faulty/crappy regulator. Are you using the same unit for both MIG and TIG?
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So you have 2 pressure gages, one to show the pressure in the tank, the other to show the pressure out to the torch, you're saying the torch side returns to 0 after the post flow times out?
Richard
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tfasbind
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I currently have the tig connected to a double regulator at the 100% argon tank ( I use the second valve of the double regulator for my mig when doing aluminum) and the mig is connected to a single regulator at the 75%argon/25%co2 tank.

I also noticed that when I first open up the tank valve for the tig, the BB in the regulator no longer spikes. It only moves when I open the regulator valve.
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What you are describing doesn't sound like a leak at all. I think you are expecting the machine to flow gas for as long as you are holding the footpedal down even when there is no arc.
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tfasbind
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The torch side dial returns to zero a few seconds after the regulator valve is set to the pressure that I want.
If I hit the foot pedal it will register pressure for a few seconds, then drop back to zero. I also noticed that when I first open the tank valve, the little BB no longer spikes on the regulator dial.
tfasbind
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Oscar, it sounds like I did not understand how the control valve works. Are you saying that the control valve will only register pressure when there is gas flowing to the torch?
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I think you need to just post pictures of what you're talking about. First you mention a BB which usually indicates that you have a flowmeter that reads the actual flowrate. Then you're talking about a dial, which then sounds like you have a regulator-flowmeter, which is an actual dial with a needle that "shows" the flowrate. I honestly can't tell what you're talking about anymore. Just post pics, yes? :)
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tfasbind
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Sorry but I misspoke when I said dial. I have an Argon Regulator Dual Co2 Flowmeter, and i was referring to the BB that floats in the flowmeter tube . I will post pictures when I learn how to do that.
https://www.amazon.com/Regulator-Flowme ... 225&sr=8-5
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Ok I see.

Here is where your wording isnt precise enough...
tfasbind wrote:I turn the machine on, open up the cylinder valve slowly all of the way, then open the gas regulator to @ 20 SCFH.
After about 5 seconds the regulator meter reading drops to zero. If I hit the foot pedal it will go back up to 20 then drop back to zero in @ 5 secs.
What you are seeing is this:

When you [initially] open the valve that controls the actual flowrate (the small valve on your dual-flowmeter/tank-regulator), the system is flowing because it is filling the gas hose that is going from your flowmeter to your machine. The internal regulator on that whole flowmeter/regulator setup is typically setup for 50psi, so it will fill the hose until the pressure in the hose reaches approximately 50psi. Once it fills up, the BB float will go down to zero because the hose is now filled; there is no more actual flow to measure because there is none (at least until you activate the TIG welder's gas solenoid).

When you hit the footpedal, it will go back up to 20 CFH because gas is actually flowing and it is the flowmeter's job to show you this, and it does, because that is what you have set it to. Then after you de-activate the solenoid via the releasing the footpedal, the flow stops and the flowmeter will tell you that nothing is flowing when it drops back down to zero, because that is what is actually happening: the flow is actually stopping because that is what it is supposed to do when the solenoid closes shut.


So in essence what you are seeing exactly what should be happening. Why you would think that there is a leak is not readily apparent because we can't see the full logic that is developing in your head for this sequence of events.

I think possibly maybe you are thinking that once you set it to "20 CFH" it should show that all the time, even when not welding/using argon, and the BB float should stay there. But that's not how things work here. That is just a guess on my part, I could be wrong in trying to deciper your individual thought pattern for this scenario.
Last edited by Oscar on Sun Dec 13, 2020 3:06 pm, edited 1 time in total.
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tfasbind
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Oscar, thank you for your in-depth explanation of how the flowmeter works and you are right that I did not understand how it should function. I thought that the BB was measuring pressure in the line (not flow) therefore I thought that it should remain and not drop unless there was a leak.
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No problem, glad to be of service. 8-)
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BugHunter
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tfasbind wrote:Oscar, thank you for your in-depth explanation of how the flowmeter works and you are right that I did not understand how it should function. I thought that the BB was measuring pressure in the line (not flow) therefore I thought that it should remain and not drop unless there was a leak.
It doesn't measure pressure, it measures flow.
tfasbind
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welding tank.jpg
welding tank.jpg (14.98 KiB) Viewed 1456 times
I wanted to learn how to attach pictures to this site....so here is a picture of my set-up.
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There ya go. Just increase the resolution a bit, and you're golden.
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