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Gas Regulator Troubleshooting

ironhorse64 is a welding expert and is adept at troubleshooting welding systems.

Gas Regulator Troubleshooting

Gas Regulator Troubleshooting

Introduction to Regulators

Why do we even need regulators? Regulators take a high-pressure gas like oxygen and reduce it to a useable pressure for uses like oxy-acetylene cutting. Oxygen cylinders are filled to a pressure of over 2,200 psi and need a regulator to reduce pressure to 30 psi to cut steel. The acetylene regulator does the same thing, but the pressures are substantially lower. Full cylinders are below 300 psi and delivery pressure is less than 15 psi.

Specifications of a Regulator

Specifications of a Regulator

Another type of regulator is called a flow gauge. These regulators take a tank pressure of 2,200 psi and drop it down to where the gauge reads in "CFH" or "cubic feet per hour." Mig and Tig welders have regulators that display CFH.

Regulators with two gauges are called "two-stage" regulators. A two-stage regulator will have a bulb on the back. This houses a second regulator or a "stage." These regulators keep the outlet pressure at a consistent level even as the cylinder pressure lowers. Research labs will frequently have this style of regulator in tandem with test equipment.

Flow Gauge

Flow Gauge

Carbon Dioxide CO2 Regulator/Flowgauge

Carbon Dioxide is one of the more versatile gases. It can be used as a shielding gas for welding, carbonation for sodas, dispensing beer, and even making dry ice. These are just a few of its uses.

Cylinders of carbon dioxide or CO2 are different than most gas cylinders. Oxygen, nitrogen, helium, and argon for example are pumped into cylinders as a gas at about 2,300 psi for larger cylinders. Carbon dioxide is pumped into the cylinder as a liquid and the pressure reaches only about 850psi. As the CO2 warms it will fill the top of the cylinder with gas and the lower portion of the cylinder will remain a liquid until a time comes where the head pressure drops and allows more of the liquid to become gas.

CO2 regulators are probably one of the more misunderstood regulators. The tank pressure gauge seems like it is always almost full and then before you know it the tank is empty. It gives you a false sense of security seeing the tank pressure reading full then suddenly the needle drops to show that you are almost out of gas. What happens is the liquid CO2 in the lower portion of the cylinder is changing to a gaseous state creating head pressure then it is used. This process is continued until the liquid is almost gone. Without the liquid to make the gas the cylinder pressure falls fast.

If the tank pressure is so unreliable, how can you tell how full the cylinder actually is? The best way is to know what size of cylinder you have. The most common cylinders are 5 lb, 10 lb, 20 lb, and 50 lb cylinders. What you want to do is to weigh the CO2 cylinder when it is full—you'll need to know the weight of the empty cylinder as well. If you have a 5 lb liquid CO2 that weighs 12 lbs full and you weigh it after using it a while and it weighs 9 lbs, you have used 3 lbs of the 5 lbs of CO2.

Carbon Dioxide Regulator

Carbon Dioxide Regulator

Carbon Dioxide Regulator

Even though this flow gauge looks radically different than the one previously discussed, its operation is the same with one exception. This CO2 regulator is used in high flow applications.

CO2 is extremely cold. If the regulator is controlling a high rate of CO2 the body of the regulator becomes cold enough that it doesn't allow the CO2 in the cylinder to warm enough to create CO2 gas. If the flow gauge isn't able to warm the liquid to a gaseous state it will spit out small pieces of dry ice.

The fins on the flow gauge create more surface area so that the flow gauge allows the ambient air to warm the regulator, thus creating CO2 gas. There are times when the flow rate is so great that these will even freeze up. If this is the case then there are finned flow gauges that you can plug into a 110v outlet to power an internal heater.

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There are CO2 regulators that do not have the float tube but use a dial gauge instead. Either way, they will read flow rate in cubic feet per hour or CFH. Be careful not to get a flow regulator confused with a pressure regulator. A pressure regulator will read in PSI not CFH.

A Word of Caution: Regulator Maintenance

If you look closely at a regulator gauge you will see the instructions "USE NO OIL." If pure oxygen or high-pressure gas comes in contact with oil it can ignite and cause a fire.

Never use oil on any gauges or regulators.

Anecdotal Experience With Oil and Regulators

I once had a customer call in and asked me if we had "EHN O" oil in stock. I had never heard of it, so I asked a coworker if he knew. He had never heard of it either so I returned to the phone and asked the customer what he was going to use it for. He replied "For my regulator—it says right on the gauge to use "EHN O" oil right on it." Then his lights came on and realized the warning was "USE NO OIL." To this day it is still my favorite story. The moral? Keep all oil products away from regulators.

Oil and Oxygen Don't Mix

The following video is an example of mixing oil and pure oxygen. The dropping of the weight is an example of the high pressure of the gas coming in contact with the oil. This is why we never use oil on regulators.

What Is Wrong With My Regulator?

It Seems Like the Cylinder of Gas Didn't Last Very Long

Leaks can happen when cylinder valves are not shut off after use. Small leaks can also happen at any place where two parts come together. How do you find leaks on a regulator? It's commonplace in other industries to look for leaks like you would in an innertube using soapy water.

When it comes to finding a leak in high-pressure cylinders or regulators, do not use soap. If you look at the label you will likely see the soap is made out of some sort of oil or petroleum-based product. Remember: Do not mix oil and oxygen. There are products out there, however, that are safe for leak detection.

Snoop!: Finding Gas Leaks Safely

Snoop! is a totally safe liquid that is applied to places where two pieces come together. Apply it at the base of gauges, inlet nipple, tank nipple, or any place you feel needs to be checked.

Apply Leak Detector—What Now?

Simply look for the bubbles. They can be very tiny bubbles that look almost like foam from small leaks or larger bubbles from larger leaks.

  • If the leaks are coming from the regulator where the gauges are screwed in, these can be "backed out" (or unscrewed) and Teflon tape can be applied and gauge turned back into regulator.
  • The same can be done for the nipple going into the regulator. Be aware that from the factory these parts are installed with Loctite and can be difficult to remove. Most regulators are made of brass and the parts can be damaged very easily.
  • If the bubbles are coming from where the nut of the regulator meets the cylinder it can occasionally be corrected by tightening the nut more to cinch it down and seal it. Be careful not to overtighten and never use Teflon tape where the nipple meets the cylinder valve.
  • If there is a large leak coming from the body of the regulator through holes in the body or through an external safety (see picture) there has been a rupture in the safety and it should be replaced by a service technician.

My Regulator Gives Me the Creeps

The biggest problem that a regulator can have is when the outlet gauge starts to rise and just keeps going until it is pegged. When this happens the diaphragm is shot and needs to be replaced. If you have a good regulator (Victor, Smith, Harris) in most cases they are worth repairing. Ask for a quote on the repair and the price of a new regulator and then decide on which option to take. If it is a cheap regulator just ditch it and get a new one. More than likely parts aren't available for them.

What Happened to My Gauges?

Periodically the needles get bent, don't return to zero, or even get totally pegged and stay. This is an easy fix. Just order up the exact size and pressure gauge as the defective one. Most gauges are 1/4" pipe thread and the 1 1/2" gauges are 1/8" pipe thread.

  • Remove the old gauge,
  • remove any dried Loctite,
  • wrap the threads of the new gauge with Teflon tape,
  • install!

You could even go into a local welding supply and they might replace the gauge for just the price of the gauge. It is just good customer service to do this and creates an impression of goodwill with the customer.

Repairs Are Simple and Safe

The external repairs of regulators are pretty simple, but if done wrong can be dangerous. If you make the mistake of putting a low-pressure gauge where the high-pressure inlet is, the gauge will explode. Remember to be careful, do not use oil, and replace gauges one at a time with the exact pressure reading gauge as the stock equipment.

If you have any questions about regulators I will do by best to answer them—comment below!

Martin Waldner on September 14, 2019:

Having problems with a high pressure nitrogen regulator. I turn it up to where i need it(200 psi) and start up the machine, it will drag down 100psi. Will stay at 200psi when the machine is not running. I cannot hear any leaks, and im thinking i could hear that big a leak. What do you think is going on?

Martin on September 14, 2019:

Having problems with a high pressure nitrogen regulator. I turn it up to where i need it(200 psi) and start up the machine, it will drag down 100psi. Will stay at 200psi when the machine is not running. I cannot hear any leaks, and im thinking i could hear that big a leak. What do you think is going on?

Terry Collins on August 06, 2019:

My regulator on my Argon tank leaked thru the tiny hole in the manifold. Should gauge be replaced?

Nick on May 26, 2016:

I am using co2 to run a mig welder, at the regulator it shows less than 2 psi but at the mig gun 35 cfh (no orifices in place )what would cause this note we have 15 other welding machines that are set between 30 - 40 psi and the cfh at mig gun is close to what the regulator reads

George on March 07, 2016:

On my 450 victor oxygen regulator when I open up the oxygen tank the regulator low side goes crazy the oxygen pours out of the safety valve what is wrong please and thanks

nitro man on March 11, 2015:

Hi. We have a nitrogen regulator and the male that fits into the nitrogen tank is worn out.. How do I change it?

serviceengineer on March 09, 2015:


I am not sure if this has been posted before but we are having a problem with our Dual stage Co2 regulators. When they are drawing gas through they sound like a chirping bird and it get louder over time. The units are around 2 years old and we have it happening on a number of different regulators. What is causing the problem?

Logical77 on January 29, 2015:

I also have a homebuilt beer kegerator setup that I put together. I was going through too much CO2 so I thought I would start with my regulator. I installed the regulator on the tank with a new washer and cut the CO2 tank on and let it set the gauges. Tank is around 700psi and my outlet is set around 12-14psi. Once that is done, I cut the tank off to see if the pressure holds or drops. Within 12 hours, the gauges are back to 0. To trouble shoot, I backed my "set screw" (adjustor for low side) all the way out so nothing was coming to the low side. When I did that, the tank pressure gauge held for over 24 hours. This leads me to believe it is in the diaphragm, low pressure gauge or my outlet valves. (I have a wye with two small check valves for attaching two lines). Is this correct? I'll try and narrow it down with a leak detector, but it is obviously a pretty slow leak... My regulator appears to be a cheap one so I doubt I can find a rebuild kit. I did take mine apart and visually inspected for damage to the diaphragm, but it appeared to be ok. Certainly soft, not brittle... Any other suggestions on how to try and track down the leak? Thanks!

ironhorse64 (author) on May 10, 2014:

You might have a bad diaphragm in you regulator. If you have an outlet gauge on your regulator and it is "pegged" I would invest in a new regulator depending on how much you paid for your regulator. Regulators can be rebuilt but those used on kegorators are usually inexpensive and more cost effective to replace.

spmaxson on May 07, 2014:

We have a beer kegerator and the beer is coming out 100 miles an hour. The gas as a result is going fast, and at 25.00 a fill, it is getting more expensive than bottles. What is wrong?

ironhorse64 (author) on May 03, 2014:

@chuckwagonne: Most regulator pressure gauges will have two gauges on it. The gauge on the right is usually the cylinder pressure that tells you how much gas is left in the tank and reads usually from 0-400 PSI. When full it will read about 250 PSI. If there is a gauge that reads from 0-30 psi with a red zone after 15 psi that will be your outlet pressure.

chuckwagonne on May 02, 2014:

Given that I can't find it online, the answer to this question must be staring me in the face, but does the cylinder pressure gauge on an oxyacetylene setup tell me how how much gas in left in the tank?

ironhorse64 (author) on March 09, 2014:

@jamikcha: If you mean it leaks where the nipple goes into the regulator you should have a piece of Teflon tape wrapped around the threads. If it leaks at the cylinder you could have a bad thread on the cga fitting or the thread on the cylinder valve. The nut and nipple should seat without any Teflon tape. Teflon tape shouldn't be used at the cga fitting.

jamikcha on March 03, 2014:

I have an Acetylene regulator, got it from ebay. When I bought it, i didn't realize that the inlet connetion was CGA 510 but my bottle takes only CGA 520 inlet connection. So, i ordered nut and nipple CGA 520 online. Removed the inlet from my regulator and installed the one i bought online. Now, my problem is that it's leaking so badly from the inlet connection thread. Any concerns or suggestion what i should do in this case? Thanks so much.

ironhorse64 (author) on August 19, 2013:

@seodress: Thanks for checking it out and glad you liked it!

anonymous on July 30, 2013:

I have a nitrogen tank regulator that isn't registering the cylinder pressure. The outlet pressure gauge is working though. Don't really know much about regulators but there doesn't really seem that there is that much which can go wrong with them.

seodress on July 05, 2013:

Very helpful lens.

ironhorse64 (author) on April 24, 2013:

@anonymous: If you are still having problems, take it to a local welding supply company and see if they can help. You might have to replace the nut and nipple if they are severely scarred from the wrench and pliers

ironhorse64 (author) on April 23, 2013:

@anonymous: The only regulators that I have seen that have left handed thread are those that are used for beverage dispensing. Make sure that it is left handed. Look for any markings around the nipple or on the back that might have an LH or Left. What I usually do when I have a stubborn nipple is to push the nut back to the body of the regulator to expose the end of the nipple that goes to the tank then find a 6 point socket that fits over the end of the nipple. Use a ratchet with the longest handle you have and use a piece of pipe over the handle of the ratchet if needed for leverage. Then apply smooth even pressure. As far as the teflon tape, it is supposed to be used for threaded connnections going into the regulator body. Some manufacturers will use lok-tite. Do not use teflon tape for the threads on the cylinder to CO2 nut connection. That is a metal to metal connection. Hope that helps.

anonymous on April 21, 2013:

I have a CO2 regulator that has a leak where the high pressure supply nipple tube fits into the regulator. It appears the tube was installed using plumber's Teflon tape as were all other fittings on the regulator. The tube is left-hand threaded. I cannot get the tube out of the regulator. I have tried with a pipe wrench and with large slip-joint pliers. It will not budge. Is there a "trick" I should know about in order to get the tube out? Thanks!

ironhorse64 (author) on March 31, 2013:

@anonymous: There is locktite placed on the threads from the factory that make it difficult. If it is a true CO2 regulator it should have a CGA 320 fitting already on the regulator. If you need to you could take it to a welding supply store and see if there is an adapter. Sound like you might have a CGA 580 for Helium, Nitrogen or argon. There is an adapter that is available that you could just screw on.

anonymous on March 26, 2013:

How much flow can I expect to come out of an E sized tank that has a pressure of 900 psi? The flow seem to max out at 4 or 5. Thanks.

anonymous on March 25, 2013:

I just changed my argon co2 mix bottle with one from my local welding supply shop. I get hardly any volume or pressure from my welding nozzle. Checked flow coming out of regulator same thing little to no pressure or volume. I pulled apart regulator seat and seals look great. does this sound like bad regulator or did they possibly give me an empty bottle. Will an oxygen regulator work just as a test to see if bottle is filled close to proper psi.? thx tman

anonymous on March 12, 2013:

I bought a CO2 regulator and need to swap out the inlet nipple that's installed ( with a rounded nose ) for one that has a flat face, to fit the CO2 tank. I can't get the nipple that's installed to come out. What's the story?

ironhorse64 (author) on February 17, 2013:

@anonymous: If you are getting frost on an oxygen regulator it can be from high consumption. When there is a high volume of oxygen used the body of the regulator becomes cold and the ambient moisture can freeze. If there is a leak you can sometimes hear it or feel it coming from the regulator. If you feel there is a leak use a liquid called snoop and it bubble where the leak is. DO NOT use any soap that is petroleum based. Check the labels.

anonymous on January 09, 2013:

Why do you get frost on an oxygen regulator, is this a sign of a leak?

ironhorse64 (author) on January 01, 2013:

@anonymous: No you cannot. Argon cylinders are filled to a pressure of about 2200 PSI and your acetylene regulator tops out at 400 PSI. It will literally blow the input gauge apart. Plus it is not good to introduce a high pressure into a regulator that has been used for a fuel gas. If you wer going to use a regulatr a helium or nitrogen would work.

anonymous on December 28, 2012:

Can I use an Acetylene regulator on an Argon tank?

ironhorse64 (author) on October 21, 2012:

@anonymous: Oxygen regulators have a different fitting than what an argon bottle will accept. Plus it is not a good idea to change fittings on the oxygen regulator to fit an argon or any other cylinder. There is a certain amount of oxygen residue left behind and can result in a fire. That is one of the reasons they have different fittings.

There is no danger in using gas regulators that have the same fitting. Argon, Nitrogen and Helium all have the same fittings and regulators can be interchanged. I strongly suggest that you find an argon, nitrogen or helium regulator to achieve your desired results.

anonymous on October 21, 2012:

can you use an oxygen reg on an argon bottle for increased flow

ironhorse64 (author) on September 22, 2012:

@anonymous: The nut and nipple will not fit onto a liquid argon. When you say liquid argon I am assuming you mean a cryogenic cylinder since all other argon's are gaseous. It is not a good idea to run any gas into a regulator that has been used for oxygen..

anonymous on September 22, 2012:

Can I use an Oxygen gauge on a Liquid Argon Bottle for regulating

ironhorse64 (author) on August 15, 2012:

@anonymous: If you have gas leaking from the relief valve you are wasting a lot of gas as well as having a safety hazard. Ice is usually from the cold oxygen freezing moisture on or around the regulator. Sometimes regulators will freeze just by high usage such as blowing glass or scrapping.

anonymous on August 09, 2012:

what if my regultor always leak from the releif valve and always ice is accumulated on the ientire regultor mwhat is the cause?

ironhorse64 (author) on July 16, 2012:

@anonymous: Sounds like the safeties are blown. Sometimes gas will come out of holes in the body of the regulator or out of safeties that look like a hex nut screwed into the body. Blown safeties happen periodically. Strange that you have so many of them. Did you buy the regulators at an auction?

anonymous on July 10, 2012:

new oxygen bottle hooked up regulator never changed the setting on pressure. turn on bottle and low pressure goes nuts and air starts coming out the release. it has been set on 30#. did this to 3 gauges. Possible all three regulators bad. the third one worked for about 5 minutes.

ironhorse64 (author) on May 15, 2012:

Sorry to have missed your question. I haven't been on Squidoo in some time. If you are using a small amount of co2 for plants there still could be some liquid co2 in the cylinder. It can have a little Co2 enough to register flow but not enough to show on the cylinder pressure side. With small usage and large cylinder this could be the case. You might want to take your regulator to a local welding supply and have them hook it up to a full cylinder and see what happens

anonymous on May 14, 2012:

while switch off regulator still gas coming

anonymous on February 29, 2012:

@ironhorse64: Thank you for your reply.

The LP does drop back down to a stable 40 psi. I forgot to mention that it is a non-adjustable single stage regulator. When I set a higher bps, it drops further down. A 2 - 3 bps would be at 20 psi while a 1 bps is 40 psi.

The raise in LP is random, I find 50 - 65 psi in the morning and when coming home I find it at 40 psi stable.

I also notice that it is a British thread instead of a CGA320, while it connect firmly, I'm not sure if I should replace the British Nut and Nipple to a CGA320. The British connection has a built in washer (white and quite large) which also came with a rubber O-ring (gasket). Would installing a CGA320 be a good idea?

ironhorse64 (author) on February 25, 2012:

@anonymous: My first thought is that the pressure gauge is defective. I would go to your co2 supplier or a welding supply in your area and ask them to hook up your regulator to a full cylinder and test it. If the pressure gauge does not show pressure and is bad they can replace it. Welding supply distributors should carry the gauge for your regulator. It might look different than the one you have but they should have something that will work. I live in the northwest and where I work we do the install for free and just pay for the gauge. Usually less than $15.

anonymous on February 24, 2012:

My regulator seems to say its empty yet the pressure bubble still shows flow when the seleniod trips. still flowing and still reads empty Ive tapped on it everything, for a week now still flowing?? bad gauge?50lb tank, viagrow reg.

ironhorse64 (author) on February 22, 2012:

@anonymous: The pressure on the low side of the regulator will read different wile gas is moving as to when it is shut off. What might also be happening is the CO2 that was once flowing through the low pressure side has now stopped flowing with the solenoid off and that gas may have warmed up do to the ambient air and has expanded creating more pressure. Does the pressure drop back down to 40 psi when the solenoid is activated?

anonymous on February 20, 2012:

I have a single stage regulator on a 5 lb Co2 tank used on aquariums.

My High pressure is steady at 800 psi while my Low pressure goes up and down depending on my needle valve settings. The whole system is hooked up to a solenoid and when I unplug the solenoid, the Low pressure raises.

At 1 bubble per second of Co2, the LP is 40 psi.

When the solenoid is off (whole system off) , my LP raises. In the morning I find it at 60 psi.

I have done leak tests, I have also purge dirt out of my solenoid. What are your thoughts about this.

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