did they send me cylinder with wrong fitting?

[Evangelos]

Hi all,

Today i received my third CO2 cylinder refill from my supplier and i have a strange problem that has me puzzled.

Of course i replaced the old washer on the regulator with a brand new one and i tried to fit it on the cylinder etc but it doesn't seal properly, gas always leaks out.

Looking more carefully on the fittings of my regulator and the gas cylinder, i noticed (first time i ever checked these), that the male screw around the needle on the cylinder is PENTAGON shaped.
On the other hand, the female part on the regulator side is HEXAGON shaped.

Am i right in thinking that this is the reason the regulator does not seal properly? Should these two screws be the same shape? Did my gas company sent me a cylinder with the wrong fittings?

Had no problem with them the previous two times, but i never actually checked the shape of these fittings ever before. I didn't have any problems fitting the regulator on their cylinders.

 

[Stuart_B]

I take it this is not a normal cylinder like a fire extinguisher as Ive never seen a cylinder with a gauge on it. Can you post pics of the differences you mention so we can see.... also who supplied the cylinder and reg'r

 

[Evangelos]

It's standard food grade CO2 6.35Kg from here: https://www.londongases.co.uk/view/aquarium-gas
And my regulator is "the barn" regulator from ebay.

 

[Stuart_B]

I dont think what you are pointing out has any relevance . It apears those nuts are holding in other parts . Its the wheel valve on top of the cylinder that controls the flow of gas to the reg and similarly the valves on the reg to the tank. Are you sure you are using the correct washer cos thats the likely sourse of the leak

 

[Evangelos]

No these parts don't hold anything. Considering the female part on the second picture is hexagon shaped i am assuming that it should match a hexagon part on the first picture so that they can lock. Currently i am screwing the regulator on the cylinder but because these two parts don't match, it never goes all the way, the don't lock and thus leakage.

Could someone confirm by looking at his cylinder and his regulator what is the shape of these two fittings in his setup ? Are they both hexagon, both pentagon or different like mine?

 

[Zeus.]

Not at home ATM so cant check

But check these images should help. One should be a male fitting and the other female

 

[jolt100]

I have two different cylinders and they are both different to yours but it looks like the nut inside the cylinder is just the gas outlet from the valve.
The regulator doesn't look like mine. Is there a stem with a large hexagon nut to connect to the cylinder? This should have a plastic washer which seats against the end of the cylinder thread and tightening the nut makes the seal. It needs to be very tight .

Cheers

 

[Daneland]

I dont think what you are pointing out has any relevance . It apears those nuts are holding in other parts . Its the wheel valve on top of the cylinder that controls the flow of gas to the reg and similarly the valves on the reg to the tank. Are you sure you are using the correct washer cos thats the likely sourse of the leak

Thats what I have thought too

 

[Evangelos]

Stuart_B was right. The hexagon and pentagon in the pictures do not come into contact at all so they are not relevant.
I managed to make a seal properly by taking off that washer that you see in the second picture and placing another identical one with a different method this time.

Seems like my original mistake was that i pushed the first washer too deep into the shaft (exactly what you can see in the second picture). The rubber ring was not making contact with anything on the cylinder's side.

For the second washer i just placed it on the regulator with a very slight push, so that it was barely hanging there. Then i screwed the regulator to the cylinder and let the "screwing" push everything into place. Voila it worked and no leakage this time.