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co2 working pressure slowly drops and bubble counter drys out fairly quickly, help

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philipraposo1982

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Joined
4 Feb 2015
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106
My co2art dual stage regulator doesn't hold the working pressure steady for very long. over time it slowly drops to approx 10 psi at which point it holds there. Is this because I have no real restrictions due to the cerges reactor? or is something wrong with my reg? Or is it a leak somewhere after the solenoid / needle valve?

My bubble counter goes dry pretty quick which makes me wonder what is going on. I have done soapy spray test and haven't found anything. I turned off the solenoid and once the pressure built up I shut the tank off and left it for 12 hours and both pressures didn't budge.

I don't know what to do but I feel like something is wrong.
 
if you have your bubble counter upside down the water will be forced out. You need to have air surrounding the outlet hole. Working pressure seems weird- if CO2 is still coming out of your diffuser at 10psi then there is no reason it would maintain a higher pressure, but thats pretty low. I'd assume a leak. Contact CO2art they'll help
 
In my experience it's quite normal that your working pressure drops during the first few days if you adjust the flow rate or after you mount the CO2 regulator on cylinder. It should stabilize (if you have no leakage).

As to the drying of you bubble counter, did you tried to use glycerine (glycerol) in it? Look at this video how the bubble counters work with the glycerine inside: .
The glycerine is more viscous and do not evaporate even under high temperatures. As a bonus, the bubbles will move very slowly in it.
 
I agree this is normal due to the low back pressure from pumping straight to a reactor. Lowering the pressure at the regulator should balance this with practice.

Water will also evaporate out of the bubble counter and glycerine is a great idea as an alternative. I have tried vacuum pump oil (because I had some) with good result but this did also eventually evaporate over time.
 
Marcel G is suggesting that it is normal for the first few days of adjustment but seems to think it should not be the case otherwise.

Chris, you are saying its normal based on the low back pressure due to the huge reactor I have. I tend to agree with this but wasn't sure if my logic was correct.

So maybe I dont have a leak at all then? Maybe 10psi is the max amount of back pressure I can get from the reactor? Is there a test I could do to confirm this?

Does this mean anyone with a cerges reactor setup similar to mine would have to have a lower working pressure?
 
Well I use an cerges style reactor as well. I don't have a CO2 art regulator so I'm not sure exactly how that is balanced but imagine it is similar to mine. When my solenoid is off there is a slight pressure build up (this shows on the gauge). When CO2 comes on there is a quick burst of CO2 bubbles before everything settles down to normal and the needle on the gauge drops a bit.

In the photo below the top gauge covers the gas in the cylinder and the lower one is the output pressure which is adjusted by the control knob. This is a very old Dennerle regulator designed for low pressure operation (They only had bubble ladder reactors then) but it did work fine with an atomiser when I tried that but I had to wind the regulator knob right in to get sufficient pressure. I start setting it up by adjusting the pressure with the solenoid open (so there is normal back pressure) and with the needle valve open as well. Then it's a question of balancing the needle valve resistance and the regulator pressures so that there is little to no increase when the solenoid is closed if that makes any sense?


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Try tightening the connections up from the regulator to the needle valve, mine did this except it fluctuated rather than held a lower pressure. The second gauge shows the pressure that is user set and should remain static all the way up to the needle valve, from a flow setting of 50psi I get a rise to 60psi when the solenoid closes, this is normal, dropping to 10psi from 50psi over time after solenoid opens is not normal. If you have set 50psi as working pressure that's what the needle valve should be receiving if the pressure is lower then there's a leak before the needle valve.

The only other occasion I have seen this when its not the regulator is if I haven't opened the co2 bottle tap enough that the regulator only runs on an initial squirt of co2 to move the first gauge to show bottle pressure but not enough to maintain flow, in this instance the first gauge pressure dropped before the second gauge followed in unison until empty, rectified by opening the bottle tap further.
 
Oh yes and another possibility that gave me similar issues once was a non return check valve not working and therefore allowing water to syphon partially back down the CO2 tube meaning a lot of pressure was needed to clear that at the start but once clear there was a big pressure drop.
 
Hi x3nith,

So I understand, your saying that the working pressure is a result of the restriction of flow through the needle valve, right?

If that's true, then I guess it only makes sense that if I am experience a working pressure drop it would be due to a leak at the point where the needle valve seals off with the regulator.

I was under the impression that the working pressure was a result of the pressure in the system beyond the needle valve. And because I have no inline diffuser I thought there wasn't enough resistance to maintain the higher pressure that was originally set too.

I highly doubt its the second option you mentioned as I have it fully opened (the bottle).

So assuming its a leak at the needle valve, how do I go about fixing it? This co2art regulator came assembled with the solenoid and needle valve all together so I don't really know how to assemble and disassemble it.

How tight do all these things need to be? Like full strength tight? Or just hand tight? Or like a certain torque?
 
Chris Jackson said:
Oh yes and another possibility that gave me similar issues once was a non return check valve not working and therefore allowing water to syphon partially back down the CO2 tube meaning a lot of pressure was needed to clear that at the start but once clear there was a big pressure drop.
Click to expand...
My bubble counter has a check valve built in. She it dries out, which seems to be pretty quickly, the only way I can get water to flow back into the line is to loosen up the cap of the bubble counter to let water fill it back up. So I don't think this is an issue either. Even with the co2 turned off (solenoid off) the bubble counter won't fill back up because the pressure in that air line holds for an indefinite amount of time. I have left it dry for 2 weeks to see if any water would flow back in. It never did.
 
philipraposo1982 said:
My bubble counter has a check valve built in. She it dries out, which seems to be pretty quickly, the only way I can get water to flow back into the line is to loosen up the cap of the bubble counter to let water fill it back up. So I don't think this is an issue either. Even with the co2 turned off (solenoid off) the bubble counter won't fill back up because the pressure in that air line holds for an indefinite amount of time. I have left it dry for 2 weeks to see if any water would flow back in. It never did.
Click to expand...

In my case there was over a metre of tube from the bubble counter to the output in my tank (It went to the filter inlet) and when off water was backfilling the pipe a little, not enough to get back to the bubble counter but still enough to block the hose and create a pressure increase. I only discovered this when I found that my bubble rate sped up later in the day once the blockage had cleared. Does your bubble rate stay constant regardless?

As you say though this scenario does sound unlikely in your system.

The needle valve unscrews from the solenoid using a small spanner and you can then reseal it with PTFE pipe sealing tape if necessary but I wouldn't mess with that if it's passed the soapy water test. Could be a faulty needle valve, I've had my regulator for about 20 years but I'm on my 3rd needle valve.
 
philipraposo1982 said:
I was under the impression that the working pressure was a result of the pressure in the system beyond the needle valve. And because I have no inline diffuser I thought there wasn't enough resistance to maintain the higher pressure that was originally set too.
Click to expand...

The needle valve provides the resistance, and to prove to myself that it wasn't my ears hearing my lips flapping in the wind I thought I would just quickly double check by unscrewing my bubble counter and releasing all the pressure in the line (I'm using an inline diffuser on my reactor), I can confirm that the second gauge needle remained at 50psi and didn't budge when I let all the pressure out the line after the needle valve, zero fluctuation. Your problem is before the needle valve.

philipraposo1982 said:
How tight do all these things need to be? Like full strength tight? Or just hand tight? Or like a certain torque?
Click to expand...

Tight enough that the problem goes away, if that's not enough undoing completely and redoing the threads with thread lock is the ultimate solution, if that's too much then get it swapped out for a different unit.

My bubble counter is dry also, the majority of the water goes up the line when the solenoid opens and pressure builds in the line after the needle valve, once my needle is initially set I don't worry about the bubble count after that, the water will make its way up the line or evaporate over a couple of weeks regardless (if it gets in the diffuser it can take a while to clear reducing its efficiency), I monitor my pH and correlate with drop checker readings, if these are out of range it tells me there's a problem much more precisely than counting bubbles. Haven't gone the route of using Glycerine although I have it to hand mainly because I don't want to inadvertently block the inline diffuser with it, water through the diffuser is bad enough but Glycerine would be a nightmare to clear, (a moisture trap further up the line after the counter would resolve this issue but it's another 2 points of failure added to the system).
 
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Can I remove everything past the needle valve and test it by setting a pressure with the needle valve in the off position? Would this work to tell me if there is a leak?

I would try and set it to 30psi with the needle valve off and turn off the tank and the main regulator adjustment knob to trap the air in the second stage and the needle valve.

Hope that makes sense, would that work?
 
philipraposo1982 said:
Can I remove everything past the needle valve and test it by setting a pressure with the needle valve in the off position? Would this work to tell me if there is a leak?

I would try and set it to 30psi with the needle valve off and turn off the tank and the main regulator adjustment knob to trap the air in the second stage and the needle valve.

Hope that makes sense, would that work?
Click to expand...

Should work I reckon and definitely worth a try that should surely reveal a leak.
 
No need for the gubbins after the needle valve to test. If the pressure in the second gauge climbs (mines roughly 10psi) when the solenoid closes and holds there then the connection from the solenoid to the regulator is okay, if the pressure drops or fluctuates when the solenoid opens and the needle valve is fully closed then the joint between the needle valve and the solenoid is not tight enough and gas is escaping, how much and how often it fluctuates is possibly influenced by the vibration from the solenoid (if that's not tight enough on it rattles about) in operation working the joint open intermitantly.
 
Makes sense. So my concern with testing the leak before the needle valve is that I may overtightened the needle valve to close and ruin it. Is this possible?

How could I ensure the needle valve is fully closed without damaging it? Thoughts?
 
Great idea thanks. I was thinking about closing it after the bubble counter being removed... Makes a lot more sense doing it your way. I will have to do this tonight and will keep you all updated on what happens.
 
so...

i took the co2 out from the cabinet and started testing again for leaks. I tried removing the smc needle valve but the nut was soo tight that it wouldn't budge. finally something came loose, but it was the other side of the solenoid and not the side i was trying to remove.

once i got that section off now the solenoid and smc valve was still attached together. I tried again grasping either end of the solenoid but no dice. i ended up rounding off the nut in between the smc valve and solenoid... the leak is more noticeable now too.. i hope co2art will send me replacement parts as I feel they over tightened these components making it near impossible to remove.

here is a little video showing the leak and the damage done to the nut. very disappointed :(
 
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