JG push fittings - not perfectly gas tight?

[Kev888]

I've been doing some tests on my CO2 setup lately and noticed a very slow leak. It wouldn't be apparent in normal service, but I've had all the lines blanked off and turned off the cylinder specifically to test - it loses pressure overnight.

I finally traced it to the JG push fittings; having linked lots together on virgin/new tube and immersed in a bowl of water, about a third of them release a teeny bubble say every two-four seconds. Its not a lot from any one connector but I estimate that with them all connected 24-7 maybe I'd lose a grand total of say half a 7kg cylinder over a year.

I suppose in a pub situation that minuscule loss wouldn't even be worth mentioning; the ease of installation, service & replacement of push fittings would pay for it many many times over, so it could be considered completely normal and acceptable. I've been using the current setup for a few years myself without noticing too. But I'm wondering if this is actually normal - have other people noticed very slow leaks?

Cheers
kev

[Blackaddler]

I've had the same sort of problem with a welding gas bottle to mig welder.

Wrapping PTFE tape around the end of the tubing can can help stop the leaks a bit.

[Kev888]

Interesting, thanks.

I did once have a problem with a whole reel of 3/8" line having a small score along its length; maybe some lines are out of tolerance or something like that.

Cheers
Kev

[djbadger]

My corney set up leaks and I haven't found the reason yet. I lost a whole cylinder of CO2 over the course of several days. Now I have put non-return valves on each line, close to the gas-in fitting, and I pressure up, turn off and leave for a day or two. I re-pressure after pouring beers, or every few days. One problem is that the gauges all read zero after half a day or so, whereas the kegs still have pressure. The non-returns prevent the gauges from showing the actual keg pressure. It may be that I have a number of tiny leaks same as you but its hard to tell as I can't submerge the tubes because they are plumbed into the kegerator.
If other people don't have this problem, there must be a way of solving it.

[Kev888]

Ah yes, thats the sort of thing, though it does sound like a 'much' faster loss than mine - I too would lose pressure by morning even with all the gas/keg lines blanked off, but it was slow enough that I wouldn't have realised with kegs connected, let alone be losing a cylinder's worth.

It may be that you could find leaks by squirting starsan or soapy water on joints etc - my leaks were too slow to spot this way but yours may not be. And from my past experience its possible theres more than one leak to fool you, for example a slow one around the regulator and a faster one on a keg lid.

In the end I got a rectangular plant trough and filled it with water then lowered in the disconnects and the bank of secondary regulators until just a tad under the gauges - after pressurising so water wouldn't get into the internals through any leak - then afterwards dried it all out thoroughly on a radiator. It was really fiddly and potentially unwise, but it did conclusively show me where the leaks were - after hours wasted testing the regulators themselves. Then when I realised what was going on, I was able to take it apart and test some of the JG fittings individually.

Cheers
Kev

[NobbyIPA]

your jg fittings o rings could be the culprit
have you tried the leaky fittngs with new o rings if you have any?
make sure your pipe work is cut ultra cleanly square

if you have no good spare ones you could try reversing the original o rings(take out o ring replace the other way round)
or try a bit of keg lube on the o rings to recondition the o ring
test with starsan for bubbles

[Kev888]

Yes, it does seem most likely to be the O-rings or the tube, unless theres some flash or something on the fitting itself. I did have a look at the O-rings on one, but couldn't see any damage or defects, though I didn't try swapping the rings - probably should have tried to as that would have nailed it down further (haven't as yet tried to take one apart carefully enough!).

I'm not short of spares, just curious to know if this is normal really; its potentially been going on for years without me realising. What surprises me in this case is that many of the fittings are either new or else nearly new so the chances of it being something I've done are fairly slim; I always make sure the tube ending is square and cleanly cut and push the tube in carefully and as squarely as possible, after that theres not much else to go wrong AFAIK. Though I could use keg lube or I've got a food grade spray oil, thats a good idea - I don't really want to, as the lube seems more likely to catch crap which could cause its own problems, but if it helps preserve the O-rings then so be it.

Sadly the starsan doesn't work very well - which may be partly why I've not noticed before when looking for bigger leaks. These are very slow and the bubbles very small, its hard to keep a seal of starsan in place long enough to be certain. But if I fully immerse it and then watch over a period of time, then its possible to see what is just trapped air escaping from the JG fitting's shell and what continues to escape and be replenished long-term.

Cheers
Kev

[djbadger]

Some good tips there for me to try. It would be fiddly but feasible to take apart my set up and dip it in a water bath like you Kev - a job for a Sunday afternoon maybe. I'd like to be able to set it with the gas tap open and leave it like that.

[Kev888]

Very best of luck, these leaks when they happen can be very frustrating so its probably worth investing the time if simple sprays aren't locating the leak.

Like I say though, for all that it worked out in my case I'm not entirely sure how wise it was to lower the regulators into water, even keeping the gauges above the surface and drying well afterwards, so unless anyone else can shed light on that then please do it with your eyes open and knowing it could be a risk.

Cheers
kev

[Dads_Ale]

Had a leak on one of my JG connections. Had to dunk in water butt to find it. Replaced the fitting and smeared a bit of silicone grease on tubing, now cured.

[Kev888]

Good to know, thanks.

Cheers
Kev