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Decreasing BPS - can’t find the cause

MrClockOff

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20 Aug 2020
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85
Location
Bournemouth
Hi all,

as per title I have an issue with decreasing BPS. I have to readjust it every morning..

I know it’s quite a common issue and I found few threads on other popular forum but all suggested solutions didn’t work..

My setup:
  • CO2 Art Pro SE regulator
  • Needle valve replaced with Aalborg VM1-BB-6A
  • about 1meter of tubing
  • Twinstar Neo diffuser medium


What’s done:
  • Leak tested with soapy water twice no leaks found
  • left the main valve shut over night - gages did not change needle positions
  • reduced tubing length from 3 meters to 1 meter
  • increased working pressure from 30psi to 40psi

but still no luck 🙁 Frustrated since bought the regulator 1,5 years ago…

Anyone came across the similar issue? How did you solve it? Please help as I don’t know what’s next?..
 

MrClockOff

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20 Aug 2020
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Location
Bournemouth
Look at your diffuser, they can become clogged and need to be cleaned or replaced. We have this problem with inline diffusers.
I have two exactly the same diffusers and I swap them every fortnight after cleaning in bleach/RO 1:3 water for about 10 hours then soaking in RO water + Prime for another 10 hours. Before replacing the clean diffuser is pre-soaked in pure RO water for few hours. Diffusers are roughly 6 months old. I’ll see if the replacement one is any different.

Again I did 3rd leak test today on every possible bit like all bubble counter parts, compression fitting, glass, connection to the needle valve, all needle valve connections, all solenoid connections and all regulator connections + both pressure gauges.. no leaks thankfully 😅

Also increased working pressure to the max 50psi which made the BPS at least stable during the day. Can’t wait until tomorrow to see if that finally solved the problem.

Still wonder if there is a way to leak test the solenoid?..
 

zozo

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Still wonder if there is a way to leak test the solenoid?..

Put pressure on the system, power off the solenoid and it should close. Then close the bottle, with a closed solenoid the working pressure gauge should still read 50psi and stay the way. Leave the bottle closed for a period and it should stay at 50psi. If not it's releasing pressure somewhere between the closed bottle valve and the solenoid.

Erratic BPS could be a temperature issue, CO² reacts pretty well to temp changes. Then if it's in a plastic tube that also is temperature-sensitive gets softer/harder and expands/contracts accordingly. It is best practice to keep a good quality hard material tubing as short as possible.

Now during the summer period, we can have a rather decent temperature swing between night ad day or from one day to another. For example, 2 days ago in my town, it was 38°C during the day, 25°C at night, and at the time of writing 20°C. It is somewhat inevitable that also the regulator can be affected by temperature differences all materials expand and contract accordingly. Might be that hobby-grade quality regulators are manufactured with less accurate tolerances. This is something you can't see from the outside. And judging from the label's description regardless of the price they are all high-quality top-notch.
 

MrClockOff

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Joined
20 Aug 2020
Messages
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Location
Bournemouth
Put pressure on the system, power off the solenoid and it should close. Then close the bottle, with a closed solenoid the working pressure gauge should still read 50psi and stay the way. Leave the bottle closed for a period and it should stay at 50psi. If not it's releasing pressure somewhere between the closed bottle valve and the solenoid.
Thanks @zozo I actually did that kind of test and pressure didn’t change after 8 hours. The only thing I did notice is that when solenoid opens the working pressure drops by 2-3 psi and increases back by 2-3psi once solenoid is shut.
 

zozo

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Thanks @zozo I actually did that kind of test and pressure didn’t change after 8 hours. The only thing I did notice is that when solenoid opens the working pressure drops by 2-3 psi and increases back by 2-3psi once solenoid is shut.

If you look at a cross-section diagram from any regulator you'll see they all have a spring-loaded disk valve and the dual stages obviously have 2 of those. My best guess is, what you experience is the reaction time of the spring load. Unfortunately, then you are most likely dealing with wear and tear or simply inferior quality.

And actually, in a minor sense, all single-stage regulators do this and to prevent it is why they came up with dual-stage regulators. Because the more springloaded valves, the gas has to pass through the more stable the set working pressure will be.

Try a harder tube... The tube also could cause this effect if it is too soft... See it as an exaggerated balloon idea. The tube blows up from the sudden pressure increase and counter pressure from the diffuser and then contracts again. That's why I also wrote to make it as short as possible.
 
Last edited:

MrClockOff

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Quick update

Spoke to CO2 Art and they suggested to check if bubble counter has any impact.

I have disconnected tubing from bubble counter in order to remove any back pressure caused by diffuser and I’ve discovered that the same issue is happening. BPS is decreasing even without connected diffuser…

So far I have ordered new bubble counter to see if that will do any different..
 

MrClockOff

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Another update

CO2 Art support suggested to open check valve inside the bubble counter and slightly shorten the check valve’s spring.
 

MrClockOff

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Another update:

Finally found the problem. It turned out there was a leak from my brand new Aalborg needle valve regulation knob. Was not expecting that at all as the needle valve has a sticker saying “leak tested”… also lost full bottle of gas…
Picture with red arrow pointing at the leak area.

The good news are that after replacing the original valve back plus after bubble counter check valve modification the bps stabilised 🙏

looking forward for response from needle valve supplier but not sure if I want this valve anymore once issue hopefully will be resolved
 

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