Help Cylinder leak

[dyingispeaceful]

Hi Everyone,
I'm quite new to this cylinder stuff. I connected a regulator flow meter to an argon cylinder for the first time in my life today. I was trying to test it for leaks and something confused me quite a bit.
My flow meter is set to zero. I turn on the cylinder valve and the pressure reaches around 1800 kPa(what I expected). Now, I turn off the valve completely and I notice the reading on my regulator drop slowly. After around 5 mins, it drops to 1400 kPa and keeps on dropping. I put my ear and hands really close to all the connections and can't feel or hear any leaks. I was expecting pressure to stay 1800 kPa and only drop when I set a non-zero rate on the flow meter as I can't fathom how the pressure is dropping.
Could someone please help me if there's anything wrong with my expectation or if there is something I'm doing wrong. I am familiar with the soapy water test and will do it later. I need to clear up my confusion first.
Thanks everyone. Cheers!

 

[TiredHorse]

Yep, sounds to me like there's a slow leak, probably in the connection rather than in the flowmeter. Did you tighten the regulator into the valve with a wrench? Hand-tight won't do it; you're holding back 1800 kPa, after all.

You already know the soapy water test, which would be what I'd recommend.

Take confidence in the fact you had already put yourself on the right track for solving the problem.

 

[dyingispeaceful]

Yep, sounds to me like there's a slow leak, probably in the connection rather than in the flowmeter. Did you tighten the regulator into the valve with a wrench? Hand-tight won't do it; you're holding back 1800 kPa, after all.

I did use a wrench to tighten but was quite paranoid not to over tighten and maybe that's what didn't let me tighten it enough. I'll try tightening it a bit more.
If the regulator doesn't exhibit any observable pressure drop with the flowmeter set to ZERO and valve closed, I'll follow up with the soapy water test.
Thank you for providing encouragement :)

 

[dyingispeaceful]

Update: I wrench tightened the connections between the cylinder and the regulator, and between the regulator and the flow meter really hard. I don't think any more tightening is practically possible and now the 18000kPa reading drops to 10000kPa in 6 hrs. Do you reckon I should be worried or is this normal? Also, do I even need a soapy water test now?

 

[TiredHorse]

The way I would look at it is that if you're not at that moment attempting to ctb, the valve itself should be closed and a slow leak between valve and regulator won't matter. If you are in the process of attempting to ctb, the flow of gas will be directed into the bag rather than out the leak --and the leak won't matter.

So I'd just keep the valve itself closed while the tank is stored and not lose sleep over it.

 

[dyingispeaceful]

The way I would look at it is that if you're not at that moment attempting to ctb, the valve itself should be closed and a slow leak between valve and regulator won't matter. If you are in the process of attempting to ctb, the flow of gas will be directed into the bag rather than out the leak --and the leak won't matter.

So I'd just keep the valve itself closed while the tank is stored and not lose sleep over it.

Thank you so much. Mind feels a lot more peaceful now.