# CO2 Cylinder pressure



## james3200 (22 Aug 2012)

Hi

Been having issues with one of my co2 sources on my main tank. I cannot work out why the following happens. Every morning there seems to not be enough pressure for the co2 to start bubbling. I have to manually open the regulator a bit to get it going, but once open its fine and consistent. This caused me some problems when I was away and it basically shut down. 

The co2 comes out of the reg, to a solenoid and then into a non return valve and into a external diffuser, around 1 foot of tubing in total. The regulator is 2 months old and I replaced the valve last week. I have the pressure set at between 2 - 2.5 trying to see if that helps but so far nothing has been 100% correct. All I can assume is that its pressure related, but the last 5kg FE did a similar thing.

Any one got some suggestions??

Many thanks
James


----------



## ian_m (22 Aug 2012)

A CO2 FE will stay at 55bar (800 psi) until all the liquid has gone (normally 2/3 liquid when full) then the pressure will start dropping.

I assume you are using a two stage regulator ?


----------



## nry (22 Aug 2012)

Can you not leave the regulator open a little bit more then?  Or perhaps open the solenoid earlier to give things time to build up?

From off, I think my diffuser takes 15 minutes or so to begin to bubble as all the pressure in the lines has gone overnight.


----------



## james3200 (22 Aug 2012)

Thanks for replies;



> I assume you are using a two stage regulator ?



Yes a JBL proflora one



> Can you not leave the regulator open a little bit more then? Or perhaps open the solenoid earlier to give things time to build up?
> 
> From off, I think my diffuser takes 15 minutes or so to begin to bubble as all the pressure in the lines has gone overnight.



If I open it a bit more then I get too high of a bubble rate, i need about 2/sec, any more and it can go up to around 4/sec. I will set the solenoid to open earlier tonight for tomorrow am, but this does not explain why it did not operate correctly when I was away from the tank for a few days..


----------



## stuwags (22 Aug 2012)

I had/have the same problem. I have to set a higher bubble rate and the gas takes 15-20 mins, as nry pointed out,to push through to the diffuser after the solenoid opens.


----------



## nry (22 Aug 2012)

Can you not turn the pressure up then turn the bubble rate down or is this done by the same dial?


----------



## stuwags (22 Aug 2012)

I use disposable welders bottles at the moment that are 36 bar and I have it fully cranked open. I think that maybe having the needle jet set to such a low bubble rate has some bearing on things. I'm using a cheap-ish eBay reg an needle valve with a JBL solenoid and thought maybe I might need something a little more like a lab standard set up for more precision.


----------



## james3200 (22 Aug 2012)

> Can you not turn the pressure up then turn the bubble rate down or is this done by the same dial?



Yes I can, it has separate adjustment for pressure/bubble rate. I am going to try and experiment a bit more today/ tomorrow am to see if I can sort this out better, but I have a feeling I will have to come up with a better solution.

On the same tank I have another external co2 diffuser running on a separate filter loop, this one never fails to start immediately, and the 7kg co2 cylinder has a run of around 20 metres as it is downstairs in the warehouse..!


----------



## geoffbark (22 Aug 2012)

Sounds that there is a problem with your reg.

Something internally is sticking i think.

As you mentioned when you leave it set at 2 bar the co2 does not flow when the soliniod opens. You have to turn up the pressure then turn it back down again to get it going, ( or free the metal blockage ).

Send the reg back!!!!!


----------



## GHNelson (22 Aug 2012)

Hi 
Try connecting a non return valve before the diffuser...this may help keep the line full of Co2....and the pressure more stable.
hoggie


----------



## GHNelson (22 Aug 2012)

Hi James
What bubble counter are you using?
Check for leaks...put it in a tub of water run the Co2 if you can.
Also check for leaks elsewhere.


If your using a glass diffuser this will fill up with tank water...after the Co2 is switched off.
Then when you re-open the solenoid it will take time for the Co2 to build up enough pressure to force the water out the diffuser.
When that happens there will be a initial gush of Co2 but it should settle down to what ever you set the needle valve too.
hoggie


----------



## geoffbark (22 Aug 2012)

hogan53 said:
			
		

> Hi James
> What bubble counter are you using?
> Check for leaks...put it in a tub of water run the Co2 if you can.
> Also check for leaks elsewhere.
> ...




This is correct, but he makes it sound as if there is no flow of co2 even if he leaves it for several hours. Which would rule this out.


----------



## GHNelson (22 Aug 2012)

Hi
Quote James (I have to manually open the regulator a bit to get it going, but once open its fine and consistent.)
Sounds as though he is losing pressure somewhere..i suspect the JBL bubble counter if this is the one he is using.
Or the connections are leaking.
hoggie


----------



## geoffbark (22 Aug 2012)

james3200 said:
			
		

> This caused me some problems when I was away and it basically shut down.
> 
> Many thanks
> James




I think we need some more info from James now.  

He needs to try your suggestion first and confirm there are no leaks. I must admit i presumed he would have done this.

And we know presumption is the mother of all ******up's


----------



## GHNelson (22 Aug 2012)

Cheers Geoffbark
I would change all the components after the solenoid valve or run a straight line to a diffuser and check if it runs consistently for a couple of hours.
Those glass diffusers usually have some water in them so it can double up as a bubble counter 
hoggie


----------



## james3200 (23 Aug 2012)

Thanks for all the ideas, here are some answers;



> Sounds that there is a problem with your reg.
> 
> Something internally is sticking i think.



I think I can rule this out. I tried putting a small bubble counter directly after the solenoid and I get a much more accurate control of bubble rate. 



> Hi
> Try connecting a non return valve before the diffuser...this may help keep the line full of Co2....and the pressure more stable.
> hoggie



I have got one already, but I have ordered a JBL co2 specific one to try out as that is what I have on the other co2 feed.



> Hi James
> What bubble counter are you using?
> Check for leaks...put it in a tub of water run the Co2 if you can.
> Also check for leaks elsewhere.
> ...



I am not using a bubble counter yet, however I just put one directly after the solenoid and I have a much better control of the bubble flow, much more accurate than just going through solenoid - non return valve - diffuser

Photo:






Last night I moved the non return valve above the diffuser by resting the solenoid onto of the reg and having the pipework go down to the reactor, and It seemed to have started better this morning, perhaps this was the problem after all..? 

Now going to try and add in the bubble counter after the solenoid and see if I still starts up OK.


----------



## geoffbark (23 Aug 2012)

It should not matter where the non return valve is positioned in relation to the diffuser!

A bubble counter as you have found is key to study co2 flow especially if injecting into a reactor that you cannot see into.

So you have tested for leaks? from reactor to regulator.

You have established an inital bubble rate?

Now fine tune that bubble rate slowly over the next week until you reach your desired co2 concentration.


----------

