[horseyfied]

Just purchased a new HTP 221 invertig. Great machine thus far but I seem to be running into a problem with my purge and wanted to run it by some of you guys before I contact someone at HTP. The machine came with its own flow meter which appears to operate properly so here's my problem. While welding, I've noticed the hotter the torch gets (air cooled) the lower my purge volume gets. I've got the meter set between 20/25 cfm and a 1.5 sec per gas setting. It starts off great, but as I continue on I notice the pre gas ( or lack there of) is pretty much gone especially when welding aluminum. I'll pull the torch away and hit the pedal and the meter ball is hovering somewhere around 10/11 and falling it seems?!?! I'll switch to stainless and same result, barely any per purge and apparently not enough to weld because every gets nasty, contaminated, sugar. Now I'm just making a guess on the torch heat, it could be a relay in the machine?? It just starts off so good and then turns into crap. Thanks in advance for any input.

Tim

[Otto Nobedder]

My guess is the restriction is in the torch, and heat-related. Make sure first that the collet and collet-body are the same size, as it's remarkably easy to stick a 3/32 collet in a 1/8 body, and not know, because it'll still hold a 3/32 tungsten. (In this case, you loose valuable contact area for cooling, and the collet expands, blocking flow. Barring this, is the collet twisted, or bulged at all along it's length? Does your gas flow return to normal when the torch cools?

Note, you'll get a big rush of gas when the solenoid opens, from the pressure built up in the line between the tank and the solenoid, but that tapers off in a second or two. Your description of it's "hot" performance (starting at 10-11, and dropping) strongly suggests a restriction in the torch... As pressure build between the flowmeter and the restriction, the flow will drop.

Steve S

[horseyfied]

Thx Steve for the info. You had mentioned the "big burst" of argon pressure. I definitely see that when first pressing on the foot. Pedal (hot or cold) then it tapers down to the set purge pressure when cold but when hot it. Goes below the set pressure and hovers around10/11 cfm. I've squirted some snoop around all the fittings and added Teflon to the machine connectors and still no luck. I'll check the hose next for some sort of blockage. Thank you again, much appreciated

Tim

[Otto Nobedder]

Keep in mind, If flow returns to normal after the torch cools, that's strong evidence for a torch-heat related problem. The symptoms do not suggest a leak.

Steve S

[horseyfied]

Hey Steve, just an update. Took my torch to work today and gutted all the OEM stuff. Added new diffuser & collet cup ect. Fired it up and again, welded great for about 5 min then no purge. Finally called HTP and they informed me that they have been having issues with the torch when it heats up around the power connect so he's sending me out a replacement, should get here Wed. Hopefully this will straighten this all out. Anywho, just wanted to give ya an update. Have a good one and thx again.

Tim

[Otto Nobedder]

Thanks, Tim,

I would not have expected the problem to be at the power-connect.

One more thing to add to the "potential problem" list....

Steve S