Gas leak detector spray
Discussion
I need to figure out where I've got a gas leak - but I'm talking about CO2 leaking from a Sodastream cylinder connected to a regulator (this is for a fish tank).
I connected everything up a couple of weeks ago, but with the CO2 output switched off. I noticed a few days ago that the pressure gauges were reading zero; I weighed the cylinder and it was down to its empty weight.
I've replaced the cylinder and reconnected, doing the nut up as tightly as I can. But still the cylinder lost about 60g of weight overnight.
So I need to figure out where it's leaking. I can't immerse it in water without tipping the cylinder on its side, which will tip the liquid CO2 and cause it to cover whichever part is leaking - so I assume this would give a "false negative". I've tried squirting the connections with "shower shine" stuff to see if it bubbled, but that didn't really work (it just ran off too quickly).
So what about gas leak detector spray? Would that detect ANY type of escaping gas, or is it specific to "Gas" with a capital G?
Any suggestions gratefully received!
I connected everything up a couple of weeks ago, but with the CO2 output switched off. I noticed a few days ago that the pressure gauges were reading zero; I weighed the cylinder and it was down to its empty weight.
I've replaced the cylinder and reconnected, doing the nut up as tightly as I can. But still the cylinder lost about 60g of weight overnight.
So I need to figure out where it's leaking. I can't immerse it in water without tipping the cylinder on its side, which will tip the liquid CO2 and cause it to cover whichever part is leaking - so I assume this would give a "false negative". I've tried squirting the connections with "shower shine" stuff to see if it bubbled, but that didn't really work (it just ran off too quickly).
So what about gas leak detector spray? Would that detect ANY type of escaping gas, or is it specific to "Gas" with a capital G?
Any suggestions gratefully received!
Edited by Dr Mike Oxgreen on Sunday 15th November 08:03
I'll try it, but when I used the shower shine stuff it just ran off too quickly. Perhaps soapy water will work better.
My suspicion is that it's leaking from the joint between the cylinder and the adapter that converts the thread to the right size for the regulator. When I screw the adapter onto the cylinder, there's hardly any resistance before I reach the end of the threads, which makes me wonder if it's not screwing tightly enough onto the nylon washer inside the threaded part.
I've never used pressurised CO2 on a fish tank before, so it's all new to me.
My suspicion is that it's leaking from the joint between the cylinder and the adapter that converts the thread to the right size for the regulator. When I screw the adapter onto the cylinder, there's hardly any resistance before I reach the end of the threads, which makes me wonder if it's not screwing tightly enough onto the nylon washer inside the threaded part.
I've never used pressurised CO2 on a fish tank before, so it's all new to me.
Edited by Dr Mike Oxgreen on Sunday 15th November 08:13
Thanks everyone!
Yes, after I thought about it a bit more I realised that PTFE tape probably isn't such a good idea. The threads shouldn't need to be leak-proof, because it's the nylon washers that make the seal. Putting PTFE tape in there just risks fragments of tape getting into the regulator or otherwise causing a blockage. There are indeed two washers: one between the regulator and the sodastream adapter, and another between the adapter and the cylinder.
I might see if I can get some more nylon washers; maybe one of them is faulty. Or perhaps putting two washers between the adapter and the cylinder will help make a better seal - at the moment I can tighten that joint (by hand) right to the point where the thread reaches its end-point without significant resistance, so I'm not convinced that it's squeezing the washer and making a nice seal.
I have been using a pretty beefy adjustable spanner to tighten the regulator's nut onto the adapter as tight as I dare (don't want to risk stripping the threads). But the adapter itself doesn't have a hex-shaped part that you can put a spanner onto, so I've been tightening that part by hand. Perhaps I should try getting a spanner onto it and see if I can do a better job. It doesn't help that the regulator and adapter came with no instructions at all.
Anyway, I've ordered a replacement CO2 cylinder which should probably arrive tomorrow. Once I've got that I'll try various methods of checking for leaks. I thought I'd smear neat washing-up liquid onto the joints and then spray with a mist of water to dilute it slightly. I can imagine that thick washing-up liquid might even seal the leak and prevent the gas showing itself.
I'll also try submersing parts of the regulator in the bath (except the gauges, I don't imagine they're necessarily watertight). I'm sceptical about this though, because the only way I can do that is to tilt the cylinder onto its side, which will possibly result in the liquid CO2 in the cylinder sealing the leak - if, for example, the leak will allow the gas to escape but not the liquid, then I won't see any bubbles. But we'll see.
If I can't see any bubbles then I'll try one more time, weighing it every hour. And ultimately I may need to get back in touch with the supplier for some tech support, or maybe it's faulty equipment...
One thing is for sure: Until I've found the source of the leak I'm not going to leave the valve on the cylinder open any more, except if I'm actively monitoring it for leaks. I can't afford to keep buying gas recharges!
Good job I'm a TVR owner, so CO2 emissions don't worry me too much!
Yes, after I thought about it a bit more I realised that PTFE tape probably isn't such a good idea. The threads shouldn't need to be leak-proof, because it's the nylon washers that make the seal. Putting PTFE tape in there just risks fragments of tape getting into the regulator or otherwise causing a blockage. There are indeed two washers: one between the regulator and the sodastream adapter, and another between the adapter and the cylinder.
I might see if I can get some more nylon washers; maybe one of them is faulty. Or perhaps putting two washers between the adapter and the cylinder will help make a better seal - at the moment I can tighten that joint (by hand) right to the point where the thread reaches its end-point without significant resistance, so I'm not convinced that it's squeezing the washer and making a nice seal.
I have been using a pretty beefy adjustable spanner to tighten the regulator's nut onto the adapter as tight as I dare (don't want to risk stripping the threads). But the adapter itself doesn't have a hex-shaped part that you can put a spanner onto, so I've been tightening that part by hand. Perhaps I should try getting a spanner onto it and see if I can do a better job. It doesn't help that the regulator and adapter came with no instructions at all.
Anyway, I've ordered a replacement CO2 cylinder which should probably arrive tomorrow. Once I've got that I'll try various methods of checking for leaks. I thought I'd smear neat washing-up liquid onto the joints and then spray with a mist of water to dilute it slightly. I can imagine that thick washing-up liquid might even seal the leak and prevent the gas showing itself.
I'll also try submersing parts of the regulator in the bath (except the gauges, I don't imagine they're necessarily watertight). I'm sceptical about this though, because the only way I can do that is to tilt the cylinder onto its side, which will possibly result in the liquid CO2 in the cylinder sealing the leak - if, for example, the leak will allow the gas to escape but not the liquid, then I won't see any bubbles. But we'll see.
If I can't see any bubbles then I'll try one more time, weighing it every hour. And ultimately I may need to get back in touch with the supplier for some tech support, or maybe it's faulty equipment...
One thing is for sure: Until I've found the source of the leak I'm not going to leave the valve on the cylinder open any more, except if I'm actively monitoring it for leaks. I can't afford to keep buying gas recharges!
Good job I'm a TVR owner, so CO2 emissions don't worry me too much!
Sheepshanks said:
There's stuff about the seal failing here - http://www.co2supermarket.co.uk/sodastream-adapter... - is that what's happening to yours?
That's a useful link, thanks! In particular, I hadn't really though about how many times you could compress and uncompress the washer before it should be replaced. I will look for a source of replacements.Edited by Dr Mike Oxgreen on Monday 16th November 13:31
Well, it appears to be a faulty regulator.
I connected up the new cylinder, and weighed everything. Then weighed again about 15 minutes later, and it had already lost a few grammes. I took it upstairs to immerse it in the bath, and in the quieter conditions I could even hear the leak. I tried tilting it onto its side and could still hear the leak, so I knew I'd be able to see bubbles in the bath.
I immersed the soda stream adaptor - no bubbles. Then I immersed the regulator nut - no bubbles. I immersed the output needle valve - no bubbles.
Then I thought, well if the regulator is at fault I might as well immerse the whole thing, even if the gauges aren't water-tight. So I did - and there was a rapid stream of bubbles coming from the base of the "working pressure" gauge, where it screw onto the body of the regulator. So that's definitely where the problem lies.
Edited to add: I will let the supplier know, and I'm confident of getting good service from them because they've already been very helpful in resolving my inability to get the CO2 indicator solution into the drop checker - this problem also turned out to be due to manufacturing tolerances, and they sent me a replacement (which worked like a charm). So hopefully they'll send me a replacement regulator and all will be well.
I connected up the new cylinder, and weighed everything. Then weighed again about 15 minutes later, and it had already lost a few grammes. I took it upstairs to immerse it in the bath, and in the quieter conditions I could even hear the leak. I tried tilting it onto its side and could still hear the leak, so I knew I'd be able to see bubbles in the bath.
I immersed the soda stream adaptor - no bubbles. Then I immersed the regulator nut - no bubbles. I immersed the output needle valve - no bubbles.
Then I thought, well if the regulator is at fault I might as well immerse the whole thing, even if the gauges aren't water-tight. So I did - and there was a rapid stream of bubbles coming from the base of the "working pressure" gauge, where it screw onto the body of the regulator. So that's definitely where the problem lies.
Edited to add: I will let the supplier know, and I'm confident of getting good service from them because they've already been very helpful in resolving my inability to get the CO2 indicator solution into the drop checker - this problem also turned out to be due to manufacturing tolerances, and they sent me a replacement (which worked like a charm). So hopefully they'll send me a replacement regulator and all will be well.
Edited by Dr Mike Oxgreen on Saturday 21st November 16:54
Gassing Station | Homes, Gardens and DIY | Top of Page | What's New | My Stuff