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ShrimpRetirement
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Discussion Starter · #1 ·
Well, as the title states guys... I don't run a solenoid (yet), and I've been manually turning the flow off/on daily via the needle valve. My operating pressure is around 40psi durring the day when I'm doing 5-6 bps via a ceramic diffuser. My question: Is it safe to strictly use the needle valve as a shutoff point, or should I use the main valve instead?

I've been practicing the needle valve only method for over 8mos now with no ill effects but I just wanted to know what other people were doing. My guess would be, over time the added pressure can diminish the precision of the needle valve?
 

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I would not use the needle valve as the shut off point, unless you know for sure that your needle valve can handle the delivery pressure (plus some more) that is coming out of the low side of your regulator.

To be honest, if you don't have a solenoid, the easiest thing to do is just let your CO2 run 24/7. If you feel that CO2 levels might rise too much during the night, you could put an air pump on a timer to come on at night. It would save you the hassle of fiddling with the needle valve everyday, and could save you the grief if you forget to turn on/off the CO2 one day.
 

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Try reducing bubble rate to 2 bps for 24/7. That's what I run on a 46 gallon and get yellow green on a 4 kdh drop checker.
 

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ShrimpRetirement
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Discussion Starter · #4 ·
Darkblade, that's not such a bad idea. I really don't mind turning the CO2 off/on via the needle valve. I've been doing it so long, I've mastered the exact point when to stop turning to get the desired bubble rate every day without looking haha. I've got a spare 5lb bottle anyway so CO2 loss is not an issue. Now all I need is an air pump and a timer.

hbos, I'll probably be toning it down a bit if I go with Darkblades suggestion.

Thanks fellas!
 

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Doesn't like Kool-Aid
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If you feel the need to shut off CO2 flow at night, never use the needle/metering valve. The reason is really not wether or not the valve can handle the pressure on it, the 25-30 psi most people run on pushing on the valve really won't be a problem on a decent valve(for example the pretty rudimentary Fabco NV-55 can handle up to 150psi - Ideals and most Swageloks more than that.). The reason you don't use a needle/metering valve for shut off service is because doing so can damage the needle in the needle/metering valve.

What most people in this hobby don't know is that good needle/metering valves have a taper and a seat. That, along with number of turns open and closed make the valve more accurate and tunable. Mashing the needle into the seat when using the valve for shut off service damages the needle and the seat. That in turn make the valve a bit less "accurate". Ideals and Swageloks absolutely fall into this catagory. You NEVER want to use an Ideal or a Swagelok for shut off service. You will eventually ruin it.

If I recall correctly the Fabcos are seated, but the needles have no taper. You * could * feasibly use the Fabco for shut off as it wouldn't flatten the needle in the valve per se, but I wouldn't advise it. You always stand the possibility of damaging the valve seat or the needle irregardless!
 

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If you feel the need to shut off CO2 flow at night, never use the needle/metering valve. The reason is really not wether or not the valve can handle the pressure on it, the 25-30 psi most people run on pushing on the valve really won't be a problem on a decent valve(for example the pretty rudimentary Fabco NV-55 can handle up to 150psi - Ideals and most Swageloks more than that.). The reason you don't use a needle/metering valve for shut off service is because doing so can damage the needle in the needle/metering valve.

What most people in this hobby don't know is that good needle/metering valves have a taper and a seat. That, along with number of turns open and closed make the valve more accurate and tunable. Mashing the needle into the seat when using the valve for shut off service damages the needle and the seat. That in turn make the valve a bit less "accurate". Ideals and Swageloks absolutely fall into this catagory. You NEVER want to use an Ideal or a Swagelok for shut off service. You will eventually ruin it.

If I recall correctly the Fabcos are seated, but the needles have no taper. You * could * feasibly use the Fabco for shut off as it wouldn't flatten the needle in the valve per se, but I wouldn't advise it. You always stand the possibility of damaging the valve seat or the needle irregardless!
This certainly makes sense. Why subject the precision needle valve to premature wear when you can turn that big knob on the co2 tank. If you are using paintbottles well, you have to turn down the working pressure.
 

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This certainly makes sense. Why subject the precision needle valve to premature wear when you can turn that big knob on the co2 tank. If you are using paintbottles well, you have to turn down the working pressure.
This would logically be an acceptable way to turn off CO2 at night. The issue with it however is that when you initially re-open the valve on the CO2 cylinder in the morning, the "rush" of CO2 into the regulator will result in a bubble rate that starts out quicker in the morning, then slows down over the course of the day.

There really is unfortunately no good way to turn CO2 on and off without a solenoid. Using the metering valve will ruin it eventually as has been discussed. Using the working pressure adjustment knob will put undue wear on the regulator's diaphragm, and using the valve on the CO2 cylinder will result in an inconsistent bubble rate over the course of the day. :frown:
 

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Hmmm, I forgot about the working pressure knob/screw adjusting the diagram and potentially causing wear. Some regulators that are available from beverage sites offer rebuild kits including, diagram for about $10.00. It doesn't look like it would be easy to rebuild though, with the high spring tension and small parts. Looking at the price of replacing worn regulators and needle/metering valves, buying a solenoid might still be the cheapest solution. I'm in the market now for a solenoid since, learning about several reasons not to run co2 24/7. :icon_conf
 

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Unfortunately, I can no longer find the Parker solenoid that was on eBay for the longest time. It was the cheapest price I saw in terms of all other solenoids.

You can, however, still get Clippard solenoids for ~$22. They get warm (some people say hot), but do feature an LED to indicate when the solenoid is on. Alternatively, you can get a Burkert solenoid; this will run a little cooler, but does not have the LED feature. It also costs more.
 
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