HVAC Pressure Testing a Refrigerant Line with Nitrogen!

[@acservicetechchannel]

Tool List- www.amazon.com/shop/acservicetech Support- www.patreon.com/acservicetech For those that are looking for the tools used in the videos: (Linked Below) Here is a link the Nitrogen Regulator amzn.to/2bXdR5f Here is a link to the Nitrogen Flow Meter amzn.to/2brvoBg Here is a link to the Air Acetylene Torch setup- amzn.to/2aQalsb Here is the Link for the Yellow Jacket Refrigerant Manifold Gauge Set used in the videos- amzn.to/2aenwTq Here is a link to Refrigerant hoses with valves used in the videos- amzn.to/2aBumVI Here is a link to the Digital Refrigerant Scale used in the videos- amzn.to/2b9oXYl ACSERVICETECH is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.

[@daviddelamaterii5801]

Video description was very understandable and informative

[@kevinblankenship2433]

The yellow hose has a ball valve on it, right off the regulator. You can have both the red and blue manifold valves open, and throttle it at the ball valve on the yellow hose. Also, you could bring it up slowly by the screw on the nitrogen regulator. This helps, if you have digital gauges that are very sensitive.

[@thisisyourcaptainspeaking2259]

Glad to see you doing this at a meaningful pressure, I see many barely pressurizing @ well below realistic values, sloppy work.

[@Honestandtruth007]

As Always Thank you Teacher Craig 🙏👍

[@guillermotejeda692]

My gauges having been equalizing the high side seems to be about 20 psi more each timeI pressurize, any idea why?

[@Louisyongcool2328]

One question can i use dye and nitrogen together to test the unit?

[@cameronstrong100]

I'm sorry, did you say both of the Schraders we're out while nitro pressure testing?

[@Brittvanegas]

Yes

[@officialmultie]

Good stuff man

[@marcolopez9476]

Where can I buy and recharge nitrogen cylinder in Texas?

[@ekie85]

Are you using dry nitrogen or nitrogen?

[@dcrickerson7611]

Another great video! Thank for all your time and effort in making these video's.

[@acservicetechchannel]

Thanks a lot DC!

[@monikarealtor2876]

Good morning My ac refrugrent line exploded under the house is it possible to perform nitrogen pressure test on already broken pipe. Please let me know

[@APEXIII]

The point of a pressure test is to see if you have leaks in the system. If you’re pipes have burst there is no point in doing the test

[@abbe6305]

when i braze in a new compressor, scroll copeland, i need to have nitrogen, its it correct that i put nitro on low side and blow out on the high side? Becuse the compressor have a rewerse seal on high side in compressor and can damage the seal?. correct? so its ok to flow nitrogen in to the compressor while braze?

[@raindogs451]

My only objection to brazing is that Stay Bright is almost always a superior connection; shear strength, tensile strength and bursting strength. Only in melting point (med gas) and sloppy connections is brazing worth a darn. Maybe dissimilar metals too. HVAC orthodoxy says "flux is evil" in spite of the fact it is used in some brazing too. Soldering is just a better connection in most applications.

[@MdRizwan-by4hp]

Thank you sir 🙏

[@acservicetechchannel]

So nice of you

[@paulkurilecz4209]

Is ten minutes at the test pressure with no pressure drop considered sufficient that only extremely small leaks exist? Is this best way to find very, very small leaks to put about 10 psig of refrigerant into the line set and evaporator and then pressure up with N2 to the test pressure? TIA

[@angelzucchet8543]

Excelent thank you 😄

[@acservicetechchannel]

Happy to help!

[@Twoface0233]

Why do you have to take the schrader cores out before brazing? And what exactly happens to the service valves if you don’t protect them?

[@marconantel7735]

They are pretty easily damaged from heat, orings and seals

[@calledout4437]

Hey thanks for the video. I'm getting ready to replace my compressor. What if I don't have nitrogen? Is there some other effective way to test? Or if I'm confident in my joints while I know it's not recommended, can I just skip the pressure test?

[@kinetic1259]

I noticed in the installation guides for some new models don't require a nitrogen pressure test anymore (at least for warranty), only confirming that the piping and units hold a vacuum of -76 cmHg (­-0.1 MPa) for 15 minutes before releasing refrigerant into the system. Still a good idea... But not technically required for warranty.

[@fastlife866]

i have a technical question.. I was on a job today. r22 two ton unit with txv. evap is clean, filters clean, good airflow, condenser is clean good airflow. my question is I have 1 degree subcooling and high superheat. aprox 80 psig lowside and 201 psig high side. suction line temperature was 75F. i have 14 degree split across both indoor unit and outdoor unit. pressures are steady no fluctuations. unit is 2006. acording to my chart it says to add refrigerant but my suction saturated temp is 50 degrees. my guess is a bad txv what do you think my issue is?

[@acservicetechchannel]

Hey Brian, was it extremely hot and humid in the house possibly and there is that much heat in the refrigerant. What was the dry bulb outside?

[@fastlife866]

acservicetech house was 79 inside, my outdoor dry was 84

[@yonkromis7883]

@@fastlife866 tell me what the chart says or let the house cool down to the right temperature and test ir again

[@fastlife866]

@@yonkromis7883 if i remember correctly i added refrigerant to bring the superheat down. Even though my pressures were higher then average the superheat n subcooling i got dialed in and it was working fine.

[@yonkromis7883]

@@fastlife866 thank you for your timely response I figured that was the thing that you did

[@geometric2194]

Do you keep your Schrader valves out still when pressure testing?

[@jayweiner977]

You can. If you have a shrader removal tool it’s best to use that. Also makes your vacuum faster.

[@zekenzy6486]

great video. thanks you

[@acservicetechchannel]

Thanks ZE!

[@80SWoods]

Do you have to use nitrogen to pressure test? I’m installing my own system and was hoping to use welding gas (argon/O2) since that’s what I have on hand. I “assume” the vacuum pump will pull anything all out anyhow when I do that step.

[@A-bone]

Don’t use argon

[@DaleKlein]

@@A-bone Why not? (beside the probably extra cost of CO2/Argon mix vs. N2)

[@joes4407]

If manual for Lg heat pump says to pressure test to 550psig but condenser has 450psig operating pressure labeled on unit, what would you recommend? Thank again.

[@acservicetechchannel]

If you have a digital manifold you can pressure test to 450 and see any drop very quickly compared to a compound gauge. If it is an older unit then only pressure test to 200 or maybe 300psi. You don't want to cause a leak, thanks!

[@khybersafi9137]

How do you flow nitrogen from one side to the other if the coil has a non-bleed TXV? Thanks.

[@exclusive_148]

Let nitro in through both sides. Then let it out

[@jimbola77]

excellent video thank you for sharing!!!!!!

[@acservicetechchannel]

Thanks jimbola77!

[@dougharsch9995]

What size nitrogen bottle and how much nitrogen is needed on a typical job for soldering lines and then pressure testing?

[@acservicetechchannel]

We use a 60cf or 40cf tank. I carry 60cf tanks in the truck and I use maybe a 1/4 of a tank each install, thanks and I have the nitrogen regulators and nitrogen flow regs that I use linked at amazon.com/shop/acservicetech

[@dougharsch9995]

@@acservicetechchannel Thanks

[@baleDELgavilan713]

Didnyou recover the refrigerant into the compresor or into a vacuum?

[@acservicetechchannel]

Initially, when taking out the old unit, the compressor internal pressure relief blew when doing the pump down as it was very weak. I just shut the valves and recovered the rest. I wanted to reuse this unit ans a testing unit at my shop. Usually you will just recover everything out and not pump down unless you are reusing a unit, thanks.

[@daryllneuburger4946]

I have recently been taught to slowly add thru the high side then slowly thru the low side I was told by adding to fast can cause the TXv to slam shut I personally have not had this happen but wondering your thoughts I have been replacing a few TXv s lately due to the installers adding the nitrogen to fast or that's what are senior tech says

[@acservicetechchannel]

That could possibly happen. It could also be the tech brazing the suction line for a long time without removing the bulb or an install brazed without nitrogen and the byproduct mixing with anti corrosives put in by the manufacturer. You should always add nitrogen into both the high and low sides at the same time. You can add it fairly quickly that way with no problem. When you say adding refrigerant into the liquid side, I am assuming that you are talking about breaking a vacuum with liquid refrigerant after doing something like a compressor changeout or weighing in refrigerant by weight per foot. Yes slowly add through the low side while on and best to use a kwik charge vaporizer to keep the compressor safe, thanks!

[@daryllneuburger4946]

thanks for your responce the way you do it was the way i was taught but i try to never stop learning the way i was taught is not always the best lol

[@acservicetechchannel]

Thanks Daryll!

[@FloridaMan7337]

Can you use Dawn dish soap as the bubble leak detector?

[@acservicetechchannel]

We try to stay away from all dish soaps now, including Dawn. Just use non corrosive bubble leak detector. It is cheap, works well, and won't corrode the pipe, thanks- If you are looking for the right kind, I have the Rectorseal version I use linked at amazon.com/shop/acservicetech thanks

[@FloridaMan7337]

What if I rinsed it off good with a neutralizer like water and vinegar? Also, does that Rectorseal work as a leak detector and braze work sealant?

[@geoffrey5239]

Nice video and just what I was looking for in installing a split unit system. I note that you did not close off the nitrogen supply until the end. Would it not be better to shut off the nitrogen supply while you are waiting to see if the pressure drops in the system ?

[@acservicetechchannel]

Yes I could have, however, I had those handles shut and the pressure in the regulator was not much more but yes, I could have taken the pressure off at the tank reg, thanks!

[@geoffrey5239]

I withdraw my comment - I did not appreciate that you had closed the manifold's connection to the Nitrogen cylinder while waiting to see if the pressure held !

[@poryeyang1854]

i was wondering if you can do a review on the best leak detectors and which one picks up better..etc..and which one you prefer most.

[@acservicetechchannel]

Thank you for letting me know what you would like to see!

[@ddcws1]

If you find a system almost completely out of refrigerant then recover the remaining refrigerant, pressure test with nitrogen and find no leaks. Should you put system under vacuum?

[@acservicetechchannel]

Hey David, yes pressure test with a digital gauge set for more precise measurements over a shorter span. If it doesn't drop after 10 minutes then there is not a leak. Remember nitrogen will still fluctuate due to temperature but very little compared to air. It could have leaked through the valve cores or there is the possibility of someone releasing it on purpose. After you get done the job, make sure to put locking caps on the ports. This way you know people are not able to get into the system without the key. The standing vacuum test will also verify no leaks, thanks a lot David and Great to hear from you!

[@MrSpartan117fan]

I build refrigeration units and the company asks for a 250 psi test for 20 minutes and nomatter what the guages will stay put for a few minutes then start dropping . I check every joint with soap and nothing . The system then holds vacuum no problem . Dont understand whats happening you have any insite?

[@acservicetechchannel]

It is possible that the setup used for pressure testing is leaking or the bottle is hotter than the system which causes the pressure to lower.

[@MrSpartan117fan]

@@acservicetechchannel I have tested my guages with soap and submerged the hoses in water and there are no leaks . If the nitogen is cool the pressure will drop when its in the system? I use a large nitrogen bottle that is around 5 feet tall in a space where the ambient temperature is around 24-25 C . Could what you said about the nitrogen be my problem?

[@acservicetechchannel]

Certainly, especially if its holding vacuum during a ten minute standing vacuum test and this same thing happens every time, thanks

[@MrSpartan117fan]

@@acservicetechchannel Thank you very much for confirming with me !

[@ashyurivillanueva6095]

SIR, GOOD DAY! WHY THE PRESSURE OF MY SUNCTION LINE IS 55PSI THEN ALL OF A SUDDEN ITS DROP IN 30PSI? BUT MY AMPERE READING IS STILL 14.4AMPS? PLEASE HELP! THANK YOU! 🙂

[@ashyurivillanueva6095]

LG MODEL: TP-C808FLA1. 72,000 BTU. R22. 3PHASE. NORMAL AMPERE 14.0A MAX 18.5A

[@JacobandAlaina]

What size nitrogen tank did you use?

[@acservicetechchannel]

60 cubic foot tank thanks

[@sergiodoordie319]

Hey great video man so u did all this work without the valves on the service ports right ?

[@acservicetechchannel]

Thats correct, I put the valve cores back in after breaking the vacuum with the refrigerant, thanks

[@tommyteamer9037]

Amazing video on showing how to do a pressure test.

[@whitesheatingairappliancer7101]

Great video thank you.

[@acservicetechchannel]

Thanks Ron!

[@wildman8601]

If the condenser has a filter already installed is it still smart to add another filter dryer in the attic ??

[@acservicetechchannel]

Just use the one to avoid any excessive pressure drops, thanks

[@wildman8601]

acservicetech ok figured but wanted to ask because you're really on point w your knowledge

[@acservicetechchannel]

Glad to help Wild Man!

[@Pretzel114]

Thanks for the video Acservicetech. For R22 if no safe psig is given you only go to 150psig then what is a limit for r410 if there is no max psig listing on the unit? Thanks again.

[@acservicetechchannel]

Most R410A Evap coils are newer and usually have a max design pressure uless they were retrofitted from r-22 to r410a with a piston or txv change.If that is the case then I still wouldn't go much higher than 150, maybe 200 at the max. If the coil is newer within the last ten years or so and cooling only then maybe test up to 250-300, thanks Nick!

[@Pretzel114]

acservicetech Thanks for the reply acservicetech. Helps expand my knowledge a little more lol. take care

[@acservicetechchannel]

Glad to help Nick!

[@ergarzavala2330]

Can you leave the gauges open when pressure testing

[@acservicetechchannel]

I wouldn't. I want as much control as possible that take out of play a possible leak in the nitrogen regulator or gauge set. Remember that when the handles are shut then the pressure is just going straight to the gauges but if the handles are open then it connects to the service hose and regulator, thanks

[@ergarzavala2330]

Thanks for the explanation

[@طارقالمخبرالتقني]

لماذا لاتخبرهو الخصائص الغاز الخطيرة السام ...والقابل للشتعال .....

[@MrMagsimus]

Thanks nice video

[@julianomartinez6080]

Question for anyone: as you can see, the technician in the vid is using the refrigerant gas gauges for the process of injecting Nitrogen to 50 PSI first, and then up to 300 PSI into the system. However those are not Nitrogen gauges. They're rather gauges for the specific refrigerant gas of that air conditioner. The only valid Nitrogen gauges are the ones connected to the Nitrogen bottle. So when he's reading "50 or 300 PSI of Nitrogen" at the refrigerant gauges, he may not have that pressure at all. The question is: what's the actual pressure he should read at the refrigerant gauges for 50 and 300 PSI of Nitrogen, respectively, and why?

[@kinetic1259]

As long as you purge your gauges and hoses with.... Wait for it... Nitrogen 😂 Beforehand, you're good to go, what you're talking about is mixing different refrigerants. Also, some refrigerants operate under different pressure ranges.

[@whitewigglesworth]

50 psi is 50psi dude. Its literally the gas pressing on the walls of the container at a pressure of fifty pounds per sqaure inch. It doesnt matter what the gauges were meant to be used with. By the way the gauges are designed to work with nitrogen and alot of different refrigerants.

[@throttlebottle5906]

you could have gotten away with saying "pounds" vs psig.

[@acservicetechchannel]

I am a teacher, what can I say, ha ha, thanks!

[@goru426]

Is it not dangerous for a person to release so much Nitrogen so close to himself? After all Nitrogen can displace oxygen from your lungs.

[@acservicetechchannel]

Nitrogen is roughly 80% of the air and this was outside so it was fine but it also very controlled as well. You want to make sure to not shoot the rubber grommet from the end as well, thanks!