Are you using a wrench to tighten the connection at the cylinder? (Sorry, have to ask the obvious stuff first...)

 

I use a wrench similar to this. It came with a beer system I have.

Its also strange that your soapy water leak test didnt show the co2 escaping from this area?

The first couple times I did soap it in the morning before tightening and it was bubbling/leaking, after tightening - no leaks.

 

Thats weird. I cant imagine why that nut would back itself off unless someone intervened. While brass is soft, it shouldn't "wear out". I think a more likely possibility is that someone could have cross threaded it at some point but you would likely sense this when starting to tighten it down by hand.

I wouldn't normally suggest using something like threadlock on these systems, but maybe a small dab would help out with this issue.

Its also strange that your soapy water leak test didnt show the co2 escaping from this area?

 

That wrench is best thrown in the trash!!! Free give aways are often that way. A good wrench is an 8-10 inch Cresent type. They have the length to give good leverage as well as have the flat jaws to avoid tearing the fitting up. Finger tight the fitting and then turn it 1/4 to 1/2 turn more and then do the soap test before opening anything else. Money saved on wrenchs is often lost on gas?

 

A good wrench is an 8-10 inch Cresent type.

I assume when you refer to crescent you're talking an adjustable wrench? ( I was always scolded in a garage for using this term since crescent is technically a brand known for making adjustable wrenches).

A better wrench is a properly sized open ended wrench.

Why not?

Because its not needed nor intended to be used in this spot. Little bits of teflon can easily get pushed into the system causing other problems later. Thats why you use a washer in between the connections. The washer should provide the seal, not the threads.

 

Adding some teflon tape may help, and ya, ditch that wrench, it is probably hurting your hand before you get it tight enough!

 

Why do people keep recommending Teflon tape on that connection?

NO!!!

 

Why not?

 

I'm way new to this, but is there any chance the nylon washers are slightly deformed?

Also I got the brass permaseal with my gla. Maybe give it a shot?

Also maybe get an expert to look at the threads.

Good luck

 

You shouldn't have any problems using an adjustable wrench on something that big, but a standard open-ended wrench would be better. Make sure you're using a nylon seal - I've found the compressed paper seals are crap, and I don't particularly like the permaseals, though others use them without problems.

First, check the nut and cylinder stem threads for damage. If all clear, finger tighten. And then use the wrench and crank that puppy. Yes, brass is a "soft" metal, but those are really big threads. I can't remember the last time I read about somebody damaging CGA nut threads by over-tightening. In fact, I'm not sure I ever have read about it. I'm sure it happens, but you'd really need to hulk out on that thing. Not something to worry about.

And when you're done, make a mark from the nut to the cylinder stem. And leak test in 3 places - both sides of the CGA nut, and where the nipple meets the regulator. Finding the nut loose is really a head-scratcher.

Also, it's a pretty big leak if a 10# cylinder lasts days. You might actually be able to hear it at that rate.

No teflon tape at that joint, please.

 

Thank you all for your suggestions and advice. I believe Kevmo figured out my particular problem (first anyway).

Make sure you're using a nylon seal - I've found the compressed paper seals are crap ...

As described above I have been using GLA nylon washers. I bought a dozen or so along with the system 3 years ago.

Recently however I noticed I was running low on washers so I picked up a few more at Airgas during my last refill after which all this began. I just asked the guy for more washers and was not specific that they be nylon or PTFE. The ones he grabbed looked "plastic" to me, but I didnt really pay attention much either as I was unaware of the subtle difference between nylon washers and the fiber washers I bought. My bad - not Airgas.

Needless to say I redid the connection using my last GLA nylon, cranked it down as usual and this morning all is well.

Now I know something new about regulators - again.
Thanks again everyone

 

I doubt that I have ever owned a Crescent wrench! That is why I refer to using a Crescent type wrench as the Crescent brand is the best known type. But the reason for the loose fitting is not much mystery at all to me. It just never got tightened. When girls from the office first started making their way into the craft jobs, this was a common problem until we got different wrenches for them to use. We used fifty pound tanks and it doesn't take long to spot the trouble when you set a tank and it's empty the next day.