# Setting up Milwaukee CO2 regulator MA957



## bartoli

Recently I set up a pressurized CO2 system using the Milwaukee CO2 regulator MA957. In the process, I discovered something. Hope others will find it useful. But first here is what I went through.

After following the instruction printed on the box to set up the regulator, the low pressure gauge started to lose pressure within a couple days (dropped from 10psi to 5psi) and the bubble rate dropped as well. Here is a part of what that instruction said:

"Turn the adjustment knob (E) clockwise until you get a reading on the low pressure gauge (F) of approx. 10 lbs or less on the inside set of numbers (psi)."

Then I came across the MA957 on-line instruction at:

http://www.milwaukeetesters.com/pdf/MA957 Regulator Set Up Procedure.pdf

It emphasized that the low pressure gauge should be ignored:

"Very slowly, turn the big knob on your regulator in until you start seeing some bubbles come out of your regulator bubble counter. Do not pay any attention to the right side gauge. All you are interested in is the bubble counter."

When I followed the on-line instruction, I reached the bubble count that I wanted (three bubbles per second) but the low pressure gauge stayed at the zero psi mark. However, within hours, the bubble count stopped. No CO2 was coming out. Then I turned the big knob a little bit to have bubbles resumed. But again, within hours, the bubbles stopped.

Then I called Milwaukee. I was told my CO2 gas was dirty and therefore my needle valve was clogged. I was asked to fix the clogged valve by following the procedure described at:

http://www.milwaukeetesters.com/pdf/clogged_needle_valve_repair.pdf

The procedure requires that I destroy the needle valve by drilling a hole through it:

'Use a 1/16" drill and go through the top hole of the needle valve and drill through the base of that hole until you feel the drill pass through into the main chamber.'

I did not want to destroy the needle valve. Thus, I did not apply the procedure. Instead, I experimented a bit with the regulator and discovered a way of getting it to work consistently.

I discovered that during the initial set-up of the regulator, I needed to keep adjusting the big knob until the low pressure gauge showed a reading of 20 psi - not 10 psi (even 15 psi was not good enough). At 20 psi, with the needle valve wide open, bubbles were flying out like water was boiling. Then I used the needle valve to reduce the bubble rate to three bubbles per second. Since then there was no lost of low pressure - the low pressure gauge stayed pointing at 20 psi. And the bubble rate stayed at three bubbles per second.

Can someone please explain why 20 psi was needed to keep a consistent bubble rate of three bubbles per second?

Better yet, can someone explain the operating principles behind a regulator? For example, what is the role of a certain low pressure level in maintaining a consistent bubble rate?

Why does Milwaukee's on-line instruction said to ignore the low pressure gauge reading and yet, at least in my case, a successful set-up requires at least a certain low pressure reading?

Thanks.


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## cbwmn

The needle valve is NOT destroyed by the drilling procedure if you stop drilling when it "thumps" through th debris. Read the procedur again. Afterrrr I performed it, I knocked out tan colored debris,not brass shavings.
Charles



bartoli said:


> Recently I set up a pressurized CO2 system using the Milwaukee CO2 regulator MA957. In the process, I discovered something. Hope others will find it useful. But first here is what I went through.
> 
> After following the instruction printed on the box to set up the regulator, the low pressure gauge started to lose pressure within a couple days (dropped from 10psi to 5psi) and the bubble rate dropped as well. Here is a part of what that instruction said:
> 
> "Turn the adjustment knob (E) clockwise until you get a reading on the low pressure gauge (F) of approx. 10 lbs or less on the inside set of numbers (psi)."
> 
> Then I came across the MA957 on-line instruction at:
> 
> http://www.milwaukeetesters.com/pdf/MA957 Regulator Set Up Procedure.pdf
> 
> It emphasized that the low pressure gauge should be ignored:
> 
> "Very slowly, turn the big knob on your regulator in until you start seeing some bubbles come out of your regulator bubble counter. Do not pay any attention to the right side gauge. All you are interested in is the bubble counter."
> 
> When I followed the on-line instruction, I reached the bubble count that I wanted (three bubbles per second) but the low pressure gauge stayed at the zero psi mark. However, within hours, the bubble count stopped. No CO2 was coming out. Then I turned the big knob a little bit to have bubbles resumed. But again, within hours, the bubbles stopped.
> 
> Then I called Milwaukee. I was told my CO2 gas was dirty and therefore my needle valve was clogged. I was asked to fix the clogged valve by following the procedure described at:
> 
> http://www.milwaukeetesters.com/pdf/clogged_needle_valve_repair.pdf
> 
> The procedure requires that I destroy the needle valve by drilling a hole through it:
> 
> 'Use a 1/16" drill and go through the top hole of the needle valve and drill through the base of that hole until you feel the drill pass through into the main chamber.'
> 
> I did not want to destroy the needle valve. Thus, I did not apply the procedure. Instead, I experimented a bit with the regulator and discovered a way of getting it to work consistently.
> 
> I discovered that during the initial set-up of the regulator, I needed to keep adjusting the big knob until the low pressure gauge showed a reading of 20 psi - not 10 psi (even 15 psi was not good enough). At 20 psi, with the needle valve wide open, bubbles were flying out like water was boiling. Then I used the needle valve to reduce the bubble rate to three bubbles per second. Since then there was no lost of low pressure - the low pressure gauge stayed pointing at 20 psi. And the bubble rate stayed at three bubbles per second.
> 
> Can someone please explain why 20 psi was needed to keep a consistent bubble rate of three bubbles per second?
> 
> Better yet, can someone explain the operating principles behind a regulator? For example, what is the role of a certain low pressure level in maintaining a consistent bubble rate?
> 
> Why does Milwaukee's on-line instruction said to ignore the low pressure gauge reading and yet, at least in my case, a successful set-up requires at least a certain low pressure reading?
> 
> Thanks.


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## bartoli

Hi Charles, thank you for the info.

When you say that drilling did not destroy the needle valve, does that mean you can still use the needle valve to adjust the bubble count?

Also, if you don't mind, did you follow the on-line set-up instruction, i.e. set up the regulator by ignoring the low pressure gauge reading and just focusing on the bubble counter? If you did, after the drilling, did you get a sustained and consistent bubble rate? Also what was your bubble rate and the psi reading on the low pressure gauge?

I try to understand how the regulator operates and the role of the low pressure gauge.

Thanks again for your reply.


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## cbwmn

Yes, I did not pay much attention to the low pressure gauge. 
I followed the factory procedure in setting the bubble rate.
The way they explain it, the low pressure gauge isn't necessary.
After drilling the needle valve orifice, the bubble count was much easier to control.
Make sure that it is the Milwaukee factory supplied needle valve. Mine has a brass knurled knob on the adjusting screw.
When drilling, be sure to back out the adjusting screw on the needle valve. 
Then you just clean out the gunk when you drill it. When it "clunks", stop drilling.
I had purchased a used Milwaukee regulator and p controller.
Good luck
Charles

It was much easier after I



bartoli said:


> Hi Charles, thank you for the info.
> 
> When you say that drilling did not destroy the needle valve, does that mean you can still use the needle valve to adjust the bubble count?
> 
> Also, if you don't mind, did you follow the on-line set-up instruction, i.e. set up the regulator by ignoring the low pressure gauge reading and just focusing on the bubble counter? If you did, after the drilling, did you get a sustained and consistent bubble rate? Also what was your bubble rate and the psi reading on the low pressure gauge?
> 
> I try to understand how the regulator operates and the role of the low pressure gauge.
> 
> Thanks again for your reply.


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## cbwmn

As I recall, they have a toll free phone number also. You can call them to make sure that your needle valve is factory supplied



bartoli said:


> Hi Charles, thank you for the info.
> 
> When you say that drilling did not destroy the needle valve, does that mean you can still use the needle valve to adjust the bubble count?
> 
> Also, if you don't mind, did you follow the on-line set-up instruction, i.e. set up the regulator by ignoring the low pressure gauge reading and just focusing on the bubble counter? If you did, after the drilling, did you get a sustained and consistent bubble rate? Also what was your bubble rate and the psi reading on the low pressure gauge?
> 
> I try to understand how the regulator operates and the role of the low pressure gauge.
> 
> Thanks again for your reply.


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## bartoli

cbwmn said:


> Yes, I did not pay much attention to the low pressure gauge.


Thanks Charles. I assume that you now have a sustained and consistent bubble rate. BTW, what is your bubble rate and what is your low pressure gauge reading?

Also, can you still use the needle valve to adjust the bubble rate?


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## cbwmn

bartoli said:


> Thanks Charles. I assume that you now have a sustained and consistent bubble rate. BTW, what is your bubble rate and what is your low pressure gauge reading?
> 
> Also, can you still use the needle valve to adjust the bubble rate?


I have 3 BPS @ 50 PSI on the low side guage.
I really am not too concerned with the BPS & PSI.
I rely on the pH controller which is set at 6.5.
As for the needle valve - IT IS NOT DAMAGED BY DRILLING OUT THE PORT.
You could perform the drilling without a power drill.
I think you could also do it by twisting the 1/16" bit with your fingers.
I did mine with an old fashioned "hurdy gurdy"
As I said B4, just make sure that it is a Milwaukee needle valve.
Charles


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## bartoli

cbwmn said:


> I have 3 BPS @ 50 PSI on the low side guage.


Very interesting... at 50 psi you get only 3 bps. My low pressure gauge stayed at zero psi when I got 3 bps. Anything above zero psi and the bubbles were flying out as if the water was boiling.



cbwmn said:


> As for the needle valve - IT IS NOT DAMAGED BY DRILLING OUT THE PORT.


Can you use your needle valve to adjust the bubble rate?


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## cbwmn

bartoli said:


> Very interesting... at 50 psi you get only 3 bps. My low pressure gauge stayed at zero psi when I got 3 bps. Anything above zero psi and the bubbles were flying out as if the water was boiling.
> 
> Can you use your needle valve to adjust the bubble rate?


Yes, just clean it out.


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## bartoli

cbwmn said:


> Yes, just clean it out.


Charles, thank you for the confirmation that you can still use the needle valve to adjust the bubble count.

I wonder what the drilling actually did to the regulator. Also, why didn't Milwaukee pre-drill all their regulators?

Thanks again for your info.


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## cbwmn

bartoli said:


> Charles, thank you for the confirmation that you can still use the needle valve to adjust the bubble count.
> 
> I wonder what the drilling actually did to the regulator. Also, why didn't Milwaukee pre-drill all their regulators?
> 
> Thanks again for your info.


BART
I don't think you arre reading the reply's.
You drill out debris, not brass.
If you don't believe me, at least believe Milwaukee.


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## bartoli

cbwmn said:


> I don't think you arre reading the reply's.
> You drill out debris, not brass.
> If you don't believe me, at least believe Milwaukee.


Hmm... I wonder what gave you the impression that I was not reading your reply? I am just trying to understand what the drilling will do to the regulator. What is puzzling to me is that if the drilling does not damage the regulator, then why doesn't Milwaukee pre-drill all their regulators?

As to believing in Milwaukee, I have some first hand experience there. As mentioned in my opening post, Milwaukee told me that the needle valve of my brand new CO2 regulator had been clogged and that I should ignore the low pressure gauge reading when setting up the CO2 regulator. It seems to me Milwaukee was wrong in both counts. My needle valve was not clogged. All I needed to do is ensuring that there is enough low pressure (around 20 psi) to provide a sustained bubble rate. When the low pressure was set to have lower than 20 psi, the low pressure and bubble rate gradually dropped.

If anyone has a different take. I like to hear them. After all, I am here trying to understand the operating principles behind the CO2 regulator.


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## rbarn

Milwakee's hang up on wanting as little pressure as possible is so the
solenoid wont leak when closed.

As long as your solenoid is not letting Co2 bypass when closed then your
PSI is not too high.

Low pressure recommendation has nothing to do with the needle valve.


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## nvision

actually, i find the needle valve and bubble rate to be less consistent if the pressure is set too low when used with a solenoid switching on/off over time. for some reason a higher pressure yields better consistency, i keep mine between 20-30.


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## cbwmn

bartoli said:


> Hmm... I wonder what gave you the impression that I was not reading your reply? I am just trying to understand what the drilling will do to the regulator. What is puzzling to me is that if the drilling does not damage the regulator, then why doesn't Milwaukee pre-drill all their regulators?
> 
> As to believing in Milwaukee, I have some first hand experience there. As mentioned in my opening post, Milwaukee told me that the needle valve of my brand new CO2 regulator had been clogged and that I should ignore the low pressure gauge reading when setting up the CO2 regulator. It seems to me Milwaukee was wrong in both counts. My needle valve was not clogged. All I needed to do is ensuring that there is enough low pressure (around 20 psi) to provide a sustained bubble rate. When the low pressure was set to have lower than 20 psi, the low pressure and bubble rate gradually dropped.
> 
> If anyone has a different take. I like to hear them. After all, I am here trying to understand the operating principles behind the CO2 regulator.





cbwmn said:


> The needle valve is NOT destroyed by the drilling procedure if you stop drilling when it "thumps" through th debris. Read the procedur again. Afterrrr I performed it, I knocked out tan colored debris,not brass shavings.
> Charles


See this:


cbwmn said:


> The needle valve is NOT destroyed by the drilling procedure if you stop drilling when it "thumps" through th debris. Read the procedur again. Afterrrr I performed it, I knocked out tan colored debris,not brass shavings.
> Charles


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## bartoli

rbarn said:


> Milwakee's hang up on wanting as little pressure as possible is so the solenoid wont leak when closed.


Yes, that too was my understanding. I wonder whether that is a common concern for all regulators or is it an issue only for Milwaukee's regulator?

BTW, I found the following quite helpful in trying to understand how a DC solenoid works:

http://www.detroitcoil.com/PAGES/How A DC Solenoid Works1.pdf


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## bartoli

nvision said:


> actually, i find the needle valve and bubble rate to be less consistent if the pressure is set too low when used with a solenoid switching on/off over time. for some reason a higher pressure yields better consistency,


I would assume that being in the regulator business Milwaukee also knew that as well. But why does Milwaukee go as far as asking its customers to completely ignore the low pressure gauge reading?

When I was on the phone with Milwaukee and brought up the observation that my low pressure gauge was at zero psi, the Milwaukee support person was noticeably upset and insisted that I should ignore the low pressure gauge reading. Why was Milwaukee so touchy about discussing the low pressure gauge reading?

I hope someone can explain the role of a low pressure gauge in having a sustained bubble rate.


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## bartoli

cbwmn said:


> See this:


Hi Charles, I am not sure what you were trying to say.


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## nvision

you probably called and got a disgruntled rep. try calling again and see if someone else answers. i do not think the low pressure gauge is entirely useless.


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## BryceM

FWIW I usually keep my Milwaukee low-side pressures around 100 psi. I replaced their needle valve with one of Rex Grigg's finer valves though. I get better overall consistency at the higher pressures.

Engineering-wise, this type of regulator is made to function correctly around 20-150 psi. At extrememly low pressures it often fluctuates. I know why Milwaukee instructions read like they do. With the kind of needle valves they use (coarse) it's about the only way to get a reasonable bubble rate. Still, it's not really using the regulator as it's designed.


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## cbwmn

bartoli said:


> Hi Charles, I am not sure what you were trying to say.


Quote:Originally Posted by bartoli 
Charles, thank you for the confirmation that you can still use the needle valve to adjust the bubble count.

I wonder what the drilling actually did to the regulator. Also, why didn't Milwaukee pre-drill all their regulators?

Thanks again for your info.End quote

B art, I was just trying to tell you that the drilling procedure just cleans out debris that is clogging the orifice.
Also, the Milwaukee needle valves ARE drilled by the factory.Why don't you try it and see if you can control the bubble count better?
Charles


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## bartoli

cbwmn said:


> B art, I was just trying to tell you that the drilling procedure just cleans out debris that is clogging the orifice.


Hmm... I thought the debris that you referred to was produced by the drilling that widens the hole through which CO2 pass through. But you are saying that those debris were already there and the drilling procedure just removes them. So, drilling does not widen the hole?



cbwmn said:


> Also, the Milwaukee needle valves ARE drilled by the factory.


When I thought the purpose of the drilling procedure was to enlarge the hole through which CO2 pass through, I wondered why the factory did not apply the drilling procedure.

But now you said the drilling procedure was just to remove debris. Since a brand new CO2 regulator has no debris, why would the factory pre-drill the needle valve?



cbwmn said:


> Why don't you try it and see if you can control the bubble count better?


Please explain what you meant by "better".

My observation suggested that when there was not enough low pressure, the bubble rate gradually dropped. That observation seems to be confirmed by various people who had posted here saying that their low pressure has to be at least a certain level.

But you seem to be suggesting that drilling the needle valve will result in sustained bubble rate "regardless" of the low pressure reading. Is that right? If so, can you please explain the reasoning behind?

Charles, I appreciate your effort of trying to help. Please bear with me and provide more information.

Please note that my username is Bartoli, NOT Bart.

Thanks.


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## bartoli

BryceM said:


> Still, it's not really using the regulator as it's designed.


Would you mind expanding on the above? I am curious.

Thanks.


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## cbwmn

This is my last comment on this thread.
I have offered you a solution to your irregular bubble count and you don't seem to want to try it.
Milwaukee told you that your needle valve was clogged and the method to clean it is posted on the Milwaukee website.
I purchased a used Milwaukee system that did have a clogged needle valve and the cleaning procedure cured that problem.

Sorry if I have offended you. 
Charles


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## giantsfan101712

Hi,

Seems im having the same problem with the bubble count...starts of fine but then dies down about 3 hours later..so i called milwaukee,they said go to there trouble shooting site and read the directions from there and you'll have no problems,so i did exactly what it said to do and it seems worse that way..with no pressure the bubbles are irregular and they just fizzle out...when i use the right gage and set the pressure around 40psi it seems to work a whole lot better...so my question is do you want a higher pressure in the right gage...and I aslo asked about the drilling and they said they dont reccomend this..its getting frustrating!!!ANY ONE HAVE EXPERIENCE WITH THIS MODEL??? I currently put it at 45 psi on the right side gauge to see if this holds...


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## nvision

you should be fine at 45psi. does the temperature in your home fluctuate a lot? might be just that...


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## giantsfan101712

Well i was also wondering about that to because my sump is in the basement along with my reactor so the temp does drop at night but the bubbles seem to stop during the day also..It seems to be holding now at 45psi but this is what its done all along only to drop later.. this is hooked up to a calcium reactor so do think that is to high of a setting...I read somwhere that to high of a setting turns the reactor into a bomb..But not sure how true that is..


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## bartoli

cbwmn said:


> This is my last comment on this thread.


Sorry to hear that.



cbwmn said:


> I have offered you a solution to your irregular bubble count and you don't seem to want to try it.


You're right on that - I did not want to try your suggestion because it includes performing _irreversible_ action on the regulator. Why would I risk damaging my regulator when it is already functioning properly?

If you'd read my opening post, you would know that I had already fixed the problem. I posted the message NOT looking for a solution - the problem was already solved. I was looking for information to help me better understand the situation.



cbwmn said:


> Milwaukee told you that your needle valve was clogged and the method to clean it is posted on the Milwaukee website.


As far as Milwaukee's reputation on technical advice, it is in the trash can! I will NOT buy any Milwaukee products unless I am confident that I won't need Milwaukee's technical support.



cbwmn said:


> I purchased a used Milwaukee system that did have a clogged needle valve and the cleaning procedure cured that problem.


Good for you.



cbwmn said:


> Sorry if I have offended you.


Not at all. I appreciate your participation in this thread. See you around!


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## mahchay

I never had any issues with mine i just set it and its perfectly normal besides the main gauge drops a bit but that's obviously from using up my CO2


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## bartoli

mahchay said:


> I never had any issues with mine i just set it and its perfectly normal besides the main gauge drops a bit but that's obviously from using up my CO2


What is your bubble rate and low pressure reading?


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## Mhappy

it does seem like anyone has really answered your question.

Within a regulator is a needle valve. This needle valve is pressed in when you turn the big knob and allows partial tank pressure (based on how much you turn the big knob) to go from one chamber to another. The pressue in one chamber is the tank pressure (around 1000) and in the other chamber is the output pressure (read by the right gauge).
Their set up tells you to ignore the right gauge because you are turning the knob with your system free flowing. The gass will flow through the system and not be read on the gauge (unless there is a significant amount of backpressure) Be aware that the right side gauge may read 20 psi but that could be because there is 50 psi going through the regulator and you have 30 psi of back pressure. If the gauge isn't blown you can try starting the system another way. (also available on youtube) Turn off the main bottle. Expel the remaining air within the regulator by letting the system run. (pretty much do what you do to change the tank). When you go to start it keep the needle valve next to the selonoid open but keep the selonoid closed. Turn the Co2 tank "on" then turn the big knob. At this point if the right gauge is working it should be increasing as you turn the big knob (if the big knob doesn't move and you feel tension on each turn than STOP TURNING IT.) ( this probably means their right side gauge isn't working (since they dont care about the right side gauge they design faulty products)). Anyway, if the pressure went up than you can use that as your working pressure. Once you turn the selonoid and the gas begins to flow the right side gauge should lower but that is only because gas is leaving the regulator. When the selonoid is off at night the pressure will read the same as it did when you set it. To control the bubble count use the needle valve next to the selonoid. 

on a side note. The Co2 regulator from milwaukee is designed to blow a safety at 60 psi. you can adjust this by tightening the screw on the side, HOWEVER THE MORE YOU TIGHTEN IT THE MORE PRESSURE IT WILL TAKE TO BLOW THE SAFETY. THE SAFETY VALVE TIGHTENED ALL THE WAY WILL BE STRONG ENOUGH TO HOLD BACK THE 1000 PSI IN THE TANK. You have a good chance of breaking the diaphram or other internal parts if you overly tighten the safety and increase the regulator pressure too high.

I got a faulty regulator and am in need of one little part that is inside. If anyone has a broken regulator I would pay for the part I need.

enjoy.


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## Bob57

I know that this is an old post,but why not buy a Fabco NV-55 needle valve(more precise and fine tuned) directly from factory(less than 25.00) and replace the one that comes with the Milwaukee regulator?


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## Left C

Bob57 said:


> I know that this is an old post,but why not buy a Fabco NV-55 needle valve(more precise and fine tuned) directly from factory(less than 25.00) and replace the one that comes with the Milwaukee regulator?


The thread sealant, Loctite, used on the stock needle valve makes it hard to remove the bubble counter and also hard to remove the needle valve from the solenoid. If you can get it off, the Fabco NV-55-18 is a good choice. If you don't want to remove the stock needle valve, you can run a better needle valve like a Fabco NV-18 with barbs inline.


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