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Air leaks

04-06-2010, 02:51 PM
Anybody out there have Gas leaks on there 200 pi. I had 2 separate leaks. One from the elbow that is on the regulator and another one on the gas start cylinoid. Took the elbows off and used teflon thread tape to seal the threads. There were some cheesy red washer looking things on the elbows that I think were supposed to seal the elbows to the body of the valves...NOT. What is really confusing is that I did not hear any leaks when I was running compressed air thru the machine. Even at 70 lbs there were no sounds of leaking air. As soon as I hooked up the argon connection the hissing started!!!! Im sure there is an explanation to this. Dont really care now for everything is sound now!!!

04-06-2010, 03:36 PM
The only leaks I've had were the connections I put together outside the unit. (LS200PI as well)

04-06-2010, 06:56 PM
I guess that I am just one of those unfortunate guys that had a bad one. Right out of the box and before I made any changes to the gas connect in the back I had the internal leaks. Every thing is good now.

04-23-2010, 06:11 PM

I had pretty much the same problem with my 200PI. Just like you, I only noticed the leak with Argon. It was obvious I had a problem when the pressure gage would drop rapidly as soon as I turned off the valve on the bottle. The flow rate was as high as 3cfm. I think it would have drained the bottle if the valve was left on over night.

My leak was also found to be on the inlet side of the solinoid valve where there were two of the red fiber washers used for the seal of the "L" fitting to the valve. I removed the valve with the hoses attached by clipping the wires so that I wouldn't have to violate the hose to hose barb connections. I got rid of one of the red washers and used teflon tape and some nasty pipe goo and after reassembly there was no more leak although I did have to pinch one of the hose clamps a bit to get rid of some bubbling on one of the hose barb connections that I may have loosened a bit moving things around. I emailed Simon prior to working on the unit and he was more than willing to handle the repairs, but I really didn't want to go to the effort and risk of shipping it off to him.

Anyone who has one of these machines should keep an eye on their gage to see if it bleeds down rapidly after the tank valve is shut off. And, be aware that Argon apparently leaks much easier than regular air.


04-23-2010, 06:51 PM
That's a good tip. Next time I use my 200PI I will check it out.

04-24-2010, 11:39 PM
The 200 pi will also leak where the hoses are attached the the back side of the regulator/ gauge. You may have to do the same repair with the tape at that fitting as well. Gregg

04-25-2010, 07:31 AM

I was luck in that none of those fittings and connections were leaking on mine other than the one barb to tube connection that leaked very slightly after I had moved things around some to swing the valve out where I could unscrew it from the "L" fitting. (I fixed it by tightening the crimp on the band.) I mixed up a soap and water solution and carefully put it on every fitting from the tank to the outlet on the front of the machine. When I was done I could close the tank valve and it would still maintain about 40psi of the original 60psi showing on the front panel gauge after about 15 to 20 hours. The only part I didn't check was along the length of each tube inside the enclosure due to the limited space. I am still amazed at the difference between Argon and air. I could hear the hiss with Argon and could not with at all with air. tking

04-25-2010, 10:27 AM
I have seen a couple of leaks on the internal solenoid units, 200PI most common. The two I have seen were simply the "L" connection was not tight enough probably due to loosening in shipping or not tight enough to keep the orientation right on the solenoid mount when assembled. Teflon tape and tightening does the job. If you have a clamp on a hose that is loose you can use a typical CV joint pliers to tighten the ring clamp or put on a screw clamp.

It is good to check by turning off your argon tank and watching for leakdown and it should be minimal. Not sure why air doesn't show the leak, it did when I checked on mine but most likely your argon pressures were lower and the higher pressure compressed air (normally 70 to 100 on most compressors) could have pushed the "O" ring to a tighter seal. Argon is not a light gas like helium so it's not the gas density issue, probably just pressure.

Great machine, little thing like this can be annoying, but really easy to fix yourself and not return. Send a note if you have any questions.

Also, I just swap different hoses on the front of the machine for plasma, tig, etc. by pushing on the barb fitting. Anyone else have a different method to change hose hookup? Works ok for me as is though.

04-25-2010, 11:17 AM
"Anyone else have a different method to change hose hookup?"

I've converted mine to a mini quick coupler with the female part attached to the 200PI and the male connector on the hoses. (thanks Keith for the parts)
I get a bit of bleed down after turning the tank valve off but I have a valve on the outbound side going to either the plasma cutter or welder and even with these valves off I get a bit of bleed down. I have gone over all fittings with bubble soap finding the connector at the flow valve is the culprit and no amount of tightening will fix it. Since this is a compression type of fitting teflon tape won't do any good. It's a very slow bleed off though so I think the loss is minimal.

08-08-2010, 01:43 AM
This has been discussed in this forum extensively under Product Support/Warranty.You have to remove the two red washers from the solenoid connection and JB weld this elbow like the factory does, the elbow will point 90 deg from where it was so their should be enough hose.I tested lines to 110 psi and found some small leaks at the hoses, use cv joint pliers to tighten them, it shouldn't take much, or replace them with Oetiker clips(their cheap).Also if you still have some trouble take off the solenoid;you will have to cut the wires and drill out the rivets and remove the paper gasket and seal with small amount of RTV sealant, retap holes and replace with screws.That is taking it to an extreme remedy though.

10-28-2010, 10:14 AM
i just go the 200pi about 2 weeks ago and have found a few thing wrong with it, including the air leak, drained a tank or argon in a day, but is there any way to change the fitting from the silp compressions to another type of connection, i think the psi gage needs a 90 on it so it would not bent and leak as much? just wondering if anybody had similer issues and what they did to resolve them on the new 200pi
thanks rob

10-28-2010, 03:09 PM
Hi Robman and welcome to the forum. We like pictures here so be sure to include some showing your work. Also, check out for the contest here. The odds of winning a great new Longevity machine are very good. Please post something about yourself in the Introduce yourself section so we can get to know you.
As for the argon fitting, Keith (KHK) has a post on the forum on using mini couplers for this connection. I have done the same with my 200PI thanks to Keith's generosity (he had an extra set). You can buy these online and they work great. As for the leaks, I would use air pressure and use bubble soap to check for the source of the leak. Most likely it is a loose hose clamp. It's best to take the air line from the solenoid back out of the unit to test so you don't get moisture inside the unit. This will not void the warranty.

10-28-2010, 04:47 PM
robman1000, do a search for "Argon Leak update." and you will see what I did with the air/argon leak problem.

10-29-2010, 06:14 AM
thanks i will check it out, i emailed simon and got a quick response from him as well.

keith is your 200pi a new version, and if so what are some good starting points for the tig setting, just cant seem to get a good stable arc.really likes to wonder and not really pin point the heat to one area thaks all for the advice

11-06-2010, 02:12 AM
Both Keith and myself have posted refits for quick connections that should go hand in hand with the argon leaks question as you can do the changeover while servicing the hoses.I found as I made corrections my leakage problems diminished porportionately, this is for the LS200PI, if you want to resolve your troubles first use some carpenter knippers,cv joint priers to tighten the original clamps first, a good way to test if they are bad is to try rotate the hoses.I used soapy water with a small acid brush and pressurized the hose and walked through every connection.At the selenoid their are two fibre washers common to acetylene torches used discard these and seal the lines with epoxy(the factory uses something like JB weld I noticed on some of my machine parts), I only did the input side of the selenoid as the other side is low pressure and the selenoid is constructed so that as the selenoid is pressurized it forces the valve inside tighter against the rubber seat of the arnature, I took mine apart, their are four screws, discarded the cardboard gasket and checked the o-ring, sealed the incoming threads to the selenoid and put a 5/16 double sided permanent type hose clamp on it.You have to remove two screws under the selenoid to remove it from the hosing to work on it but you can't cut the lines so it is good if you have it on a bench or tig stand, the line going to the front of the machine will be reoriented and was just long enough to work on my machine as the original wire clamp with the clamptite I used cut a part of the hose because the selenoid line was to short to make a two wire clamps so I used the double sided clamp here.Then connected my lines to the quick change connector. Also you will probably have to tighten the nut on the gauge hose, mine was not tight. Above all else you have to work very carefully when doing these upgrades.My hose seal so well now that I would not worry about forgeting to shut the argon off after welding.My thermal arc has a two gauge type of flow gauge which uses pressure and it can sit for a week without moving, thats how well it holds pressure but that is 75/25 argon/co2, this could easily sit for a couple of days, but I really hunted down the leaks and the work in setting up my connections to made sure my work was done well. Here are some pics of the selonid before work, I have some pics of the completed work but they are on a different camera, will post asap.As for quick connections their is a thread on it and you have to decide what is best for you.

11-06-2010, 08:08 AM
Great photos and information, thanks.

12-08-2010, 09:13 AM
I've got a leak at the back of the machine on the quick connect there. If the hose going in is slightly off angle or gets disturbed it will leak like crazy. I want to replace this fitting with some type of quick connect, but something more robust than the push type that comes with it. Any suggestions?

12-14-2010, 11:58 PM
Look through some of the posts on leaks and quick connections, the best that you can get would probably be a mini coupler for acetylene, I wanted to go with something small but actually when you go the way keith and I have it looks factory when done, the airline quick connect is a cheaper way to go the acetylene quick connect can be pricy, also when you are doing this it is a good time to change your clamps where needed, oh you could probably use a hydraulic mini coupler too, I know this has been found to be an issue, I hope it will get corrected at the factory, but the lose is very little, and I have a good seal but would never leave my tank on any of my machines.

12-15-2010, 06:54 AM
The new machines now have a coupler on them and should be much better.
I have a question though, in your post above with the images it sounds like you took the solenoid apart to do some sealing. If so what exactly did you do there. I have tested all connections on my 200PI and have no leaks at the hose fittings but when I close the valve on the argon tank the pressure bleeds down in only a couple of minutes so I still have a leak somewhere.

12-15-2010, 12:59 PM
robman, you ever figure out the settings for your machine? if ya havent and havin some troubles, please sir, ask away.... there is a plethora of knowledge and experience on this forum

12-21-2010, 03:06 AM
Gadget will post the pics I have for my solenoid, I don't think it would be the solenoid, I keep saying that I will post pics but recently transferred the images off the camera and thought they were on a usb dongle but they weren't but did not delete from camera so I will make a point of doing it this week.The solenoid has an o-ring around the armature, so it does a make a good seal you can pressure up the system and check for leaks around the solenoid,(use soapy water and acid brush) it seems like it is designed to use the pressure of the gas to force the armature against the seat, you'll see, it is not hard to do perhaps you can take it out by removing the two screws at the bottom of the case, and moving the solenoid to the side of the chassis, then remove the four screws used to hold it together, pull the top black cover off and get rid of the paper insulator, Simon had told me not to use the paper gasket so this is the only one so it must be it, it will allow a tighter fit, you can see that the o-ring and either replace it or put some oil(very little) and hope it swells some, it doesn't look like a standard o-ring, but if you have an o-ring kit swap it out, you can also look inside the armature where their is a rubber seal that pushes against the seat.Before I would replace the solenoid, or take it apart I would replace all the clamps with the double sided type we have been talking about on this forum because it is a very cheap solution.This solenoid can be replaced with a more durable unit they are common products, you shouldn't have to in a new machine.
By what you are saying their is a fair leak and would be bothersome if you are welding for several hours although in real life isn't much volume.I would get rid of the red washers at the solenoid(both while your at it) and epoxy or jb weld the connection at the input of the solenoid; absolutely, check you pressure gauge nuts to see it they are loose.The mating surface of the solenoid were cleaned when I had it apart.
I'll see how my machine weathers over time but am very happy with the way I set it up, and proud of it.
I checked some of the other connections inside my machine and they are so tight you cannot rotate the lines, so don't know what to say about the reason they leak.

12-21-2010, 06:56 AM
I've already replaced all the clamps in the machine and bubble soap tested all connections and get no bubbles. I removed the fiber washers and epoxied the fitting in too. Still when you close the valve on the tank, the pressure bleeds down within a minute or so. If I close the ball valve between the tank and the welder it will hold pressure overnight. So, the valve is the last thing it could be. I did all my testing with air pressure at 70PSI, I wonder if argon is a lighter gas and would leak where air might not though. I may test the unit with bubble soap with argon pressure instead of air and see what that does.
I don't know if the leak really loses that much volume in the use of a tank of argon but my 80CF tank sure runs out fast. I've since switched to a 300CF tank, that will give me a lot more time between fills.

12-24-2010, 03:23 PM
I went through the supply lines again with bubble soap today and found my leak. I was looking for tiny bubbles but this one was a big leak and just blew a big bubble very quickly before it burst. I must not have gotten that area covered with the bubble soap before. Anyway, the leak was in my plumbing not inside the welder and I sealed the joing with teflon tape.
Now when I turn the gas off at the tank the pressure will hold in the line for about 4 hours before it bleeds off, I can certainly live with that.
All in all it was a good day, argon leak fixed, bubbly weld issue solved. I even worked a bug out of the lathe and it is cutting much better now.

12-26-2010, 05:54 PM
If you look at the pics of the machine with the cover off it becomes apparent how much you are getting for your moneys worth.
I left the fibre washer on the output side of my solenoid because it is not under pressure, but at some point will epoxy the connection and remove the washer, clamps were replaced.
Also I want to also point out that if you cannot pinpoint leaks you can also look at the regulator over pressure relief valve.
When finished the change over new clamps and quick connections the job looked professional, but if you are using 1/4 inch double sided clamps for the torch lines you have to stick a punch inside to expand them abit to slide over the hoses, it is a permanent connection.
Again the clamp sizes are 1/4 and 5/16.

Merry Christmas and a Happy New Year all!

12-26-2010, 06:24 PM
Thanks Tigqk. I guess I'm going to have to take mine apart and check it. The Oetker type clamps as shown in your picture do work really well - way superior to the screw type, but as you mentioned, are single use, and have to be cut off to remove. They do seem to be a little hard to find around here though.

12-26-2010, 07:37 PM
Thats what I thought, but my local automotive supplier had them just had to show them a picture, Acklands also has them in the catolog online in the welding section.If you have not removed your fibre washer at the solenoid inlet do that, then jb weld or epoxy the joint in. Another alternative could be to get oxygen type barb ball connections and screw then onto the solenoid...nah.