A/C Leak Test, Evac and Recharge (ALL R134a Systems)

[@ScannerDanner]

Thank you everyone for the education! Maybe if I could see up close without my reading glasses I would have noticed the white plug covering the adjustment screw 😂 You guys are awesome. The only downside to me doing something dumb on camera, with a community as sharp as you guys, is I get to hear about it a thousand times 😋 But I'll take it any day of the week. I learn from you guys too!! More than you know.

[@TermoneenyCC]

Were just here to keep you right :) but seriously thanks once again for another great informative video Paul

[@zeke112964]

I'll be 57 this year and I try to learn something new every day

[@simonilett998]

My favourite saying is: If I'm not learning something new every day, there's something wrong...(or it's time to find a new line of work)🤣👍🇦🇺

[@chriscrusader5412]

Yeah man, sorry bout that, I wrote my first comment thinking I would be helping you, then I read all the other comments saying basically the same thing. But it took me so long to type it out I left it lol! I was thinking cool I could possibly help Danner which has been helping all of us for so long!

[@throttlebottle5906]

yells "4 eyes" while pointing at the screen, while adjusting glasses to read the screen. lol ;)

[@ecaparts]

The small white caps on the front of the gauges are for zeroing the gauge. Turn the small screw (probably counter-clockwise) to zero

[@gregreed986]

I work on residential A/C systems and watching your video's made me confident to try this for the first time on my GMC Sierra. I bought a new condenser and replaced it myself. I used nitrogen to leak test, pulled a vacuum and recharged with 1234YF refrigerant. That was the most expensive part. Ouch! Thanks to you and a few others, my A/C is perfect now.

[@ScannerDanner]

awesome! Thank you Greg

[@MatthewHolevinski]

Scanner Danner, getting old, starting to gravitate to those recreational vehicles and that comfortable A/C.

[@tyree9055]

🤣😆😅

[@ChristisKing7749]

Ive learned more about charging AC from this video than any other I have watched.

[@brianburke7440]

Do not let low pressure gauge 'see' too much pressure, the brass tube bends to a larger curve. That throws off the "zero/vacuum" setting. Love your stuff, great help to us all.

[@ScannerDanner]

Exactly what happened

[@frankiev-tech4630]

Yeah my brotha! This is hands down my money jobs...I love a/c repairs...and you nailed the leak. When you live in Florida... the heat is almost year round scorching weather, people will pay whatever. But my method with finding a leak is using an a/c recovery machine. I vacuum 5 min, and recharge 8oz, and quickly spray soapy water. I usually find it within 5 minutes. As soon as I find it...recover the freon quickly and really you don't lose much freon...beats getting nitro. I nail it everytime with this method and better than that obsolete sniffing detector crap...and I still slip in the freon lost as part of a diagnostic fee and get that money back😉😉 man and you got me sold on getting a thermo cam...it's also a great tool on finding parasitic draws.

[@stationaryenginesworldwide]

Great video Caleb and Paul.you two work together so well ...been following you for years now and love being a premium member.. Keep up the awesome work!

[@ScannerDanner]

Thank you so much!

[@simonilett998]

Hey Paul, love your work man. The white plugs on the front of the gauges are the access ports for the needle adjustment screws. Also it's possible a high spike in pressure when introducing the nitrogen to the system can ping the gauge and stress the bourden tube inside and throw out it's calibration. Another cause could be leaving pressure in the gauges when storing them, or leaving the valves closed when stored in hot weather/vehicle etc may also do them same👍🇦🇺

[@joeo1357]

Just seen your post..

[@Flowtester1]

I swear he knows that. I think his channel is were I learned how to zero the gauge. Just pop the white plug out on the face and turn the flat head screw. On my gauges the white plug got loose after I did it the first time. I might of got a little rough getting it out.

[@throttlebottle5906]

@@Flowtester1 I have seen cheapo gauges, without the hole drilled and just a white sticker or scuffed spot on lens there! lol cheap cheap cheap go the birdies

[@ScannerDanner]

@Trevor um no, that's not me, if you'd watch more of my stuff, I get things wrong all the time and always show my mistakes. Sorry you feel this way, maybe we had an unpleasant exchange in the past or something?

[@ScannerDanner]

@Simon llett I believe you are absolutely spot on. When I nitrogen charged this system to 250psi, it stressed the tube. Even though the low side gauge has a max number listed on it for 350, it still tweaked it. Great tip on leaving psi in the gauges too! I never do but others may. Thanks!

[@8953147]

That was a great refresher on charging air conditioning systems, especially the HOT water method that was 'cool' Paul. You mentioned that method before but now seeing it done was spectacular!!

[@ScannerDanner]

thank you jake!

[@robertmedina6875]

I use strait simple green!! Awesome video Paul and Caleb!!!I just wanna take a chance to say I have become addicted to ScannerDanner premium! I listen to it when I’m walking the dog, I listen to it when I am driving in the car, I listen to it while everyone else is watching TV, end it is awesome because if I don’t quite get a lecture I can go back and play it again and again. Thank you Paul and Caleb for your hard work to bring us Quality content! God bless you!

[@ScannerDanner]

Thank you Robert!

[@GeminiSeven43]

I always use simple green as it foams like crazy with the slightest pressure. Great Video as always.

[@tankabbot22]

Paul (Butterfingers Danner) lol! Love you Paul and Kaleb. Watching you for years, sat with you at ASA 2019. You are an icon , and an inspiration to all techs around the world. Thank you for all the great videos!❤️

[@ScannerDanner]

🤣 thank you my friend

[@nelsonvergara8932]

Your idea of charging it with the engine off is very smart, in your engine set up you don’t have engine fumes in your face while you’re working

[@PistonShack]

Hi Paul, Great work! Time to check AC system on my 2001 Volvo V70XC. It hasn't been touched since new. Last couple years AC started occasionally turning off if outside temperature 30C (80F) or higher.

[@Russell_Duncan]

I’ve only ever done A/C repairs using an automatic machine. Wish I’d had the privilege of learning using manifold gauges and good solid theory. I learned a lot from this video Paul (& Caleb), thanks for sharing this stuff.

[@LynxStarAuto]

Automatic machines suck, but they have one thing about them that makes them worth it... They can extract the oil out a system in seconds. You can't do that with manual gauges unless you are flushing.

[@superbestdad]

I’m laughing about the the gauge. That’s me for sure, tapping the crap out of the gauge right on the white plug that gives access to the adjusting screw. Love the content, I always appreciate everything you upload. Been a mechanic since 91 and still learning, even the crap I should’ve already known. Thanks!

[@MrBooMY3]

I was about to come and tell him that. Pretty sure the adjustment screw is under that white plug on the front of said cheap ass gauge. I have the same set. Charged MANY ACs with it. Mine is maybe 1 psi off. Been too lazy to adjust it.

[@ScannerDanner]

I believe you were the first to comment about the plug and adjustment. Thank you!

[@klausmikaelson214]

From my experience those o-rings will leak again eventually if they are not OIL resistance type, in HVAC we use the Green o-rings (oil-resistance), very nice work with refrigerants for a mechanic!

[@scientist100]

I was concerned that the black o-rings are strong but for AC, I wasn't sure. I choose green rings when I bought them in a kit, too bad they are not universal but even smaller ones will still seal even when stretched a little.

[@ScannerDanner]

this drawer in my toolbox that I pulled them from, were all AC o-rings. I believe I will be okay, but you may be right

[@Usmanthemecano]

German cars use violet colored orings..

[@LynxStarAuto]

@@Usmanthemecano I work on German cars for a living. It's the same thing. Some use yellow o-rings too. As long as they are hvac rated you are fine.

[@rubenceballos2632]

Thanks!

[@liquidrockaquatics3900]

Thank you for showing how to properly store your gauges. That was one thing I wasn’t sure about, but it makes sense and hopefully will prevent any damage from long-term pressure exposure

[@frugalprepper]

I use an old fridge compressor that also took 134a, as my vacuum pump. I also have a 30lb tank that I recover into. I can hook up the fridge compressor to the low side, hook up my tank to the high side of the fridge compressor, and put the 30lb tank in a 5 gallon bucket with some ice. It will vac down the system and recover the 134a into the 30lb tank. If I am sure it was a clean system then I will just reuse it from the tank, but if it's questionable then I take it down to my friends shop and let him put it in his recycler.

[@ScannerDanner]

This is an awesome idea! Was just thinking of something similar

[@Mr2004MCSS]

Thanks for this video. I enjoyed it and it refreshed some things that I have forgotten. I've been DIYing AC repairs since 2006. I hated charging using the small cans so I ended up buying a refrigerant scale for the 30 pound tanks and bought some tanks. It makes recharging so much easier. Set the scale for the charge amount and then wait for the alarm to go off to say it's done. As others have stated, most gauge sets have a small screw in the face of the gauges that let you zero out the needles. I have Robinair gauges and occasionally I have to zero them out.

[@isalmankhan1]

First of all Love your gear SD, looking cool😎 In the beginning of the video, I was guessing the compressor is a Denso unit by the shape of the clutch, but the A/C system sticker explained it all👍 Thanks for sharing SD, & Special Thanks to Caleb, Stay Safe Guy's❤

[@jkbrown5496]

Get a couple spare service port caps. Drill a small hole in them. Use these caps, spray with leak detection liquid, check for bubbles at the hole, wipe off. Then replace these test caps with the regular ones. No leak detection liquid in the schraders.

[@MarioDallaRiva]

40 footer! I still can't get over that. Nice video, ragazzi. Nice to have cool air when you need it. And no leaks!

[@zeke112964]

@35:30 you're at 30psi on the low you said to add 4 psi.....You initially stated it was reading 4 psi without pressure so you should subtract 4 not add it! At around 28 psi your evaporator would be 32° and would start freezing up so your system would need more refrigerant.

[@nandor690]

I was blown away when you said 4 pounds. Our 40 foot busses holds 19 and our articulating busses hold almost 40 pounds. Earlier in the video when I seen you holding the 12 ounces cans, I thought, that’s gonna be a lot of cans 🤣

[@ScannerDanner]

The difference with this RV is it has two roof mounted AC units. The front AC system is really made to just keep the driver comfortable and was never able to cool the entire RV. Make sense?

[@craigbaggett3370]

The front of the gauge screws off and you can calibrate it with your Handy Dandy Scanner Danner screw driver 😊

[@zmotorsports62]

Great video Paul. You must be living right with the easy repair of merely an O-ring right at the compressor. Thank you for the plug of my channel. I really appreciate the mention.Safe travels to you and your family and God bless. Remember if you ever travel through my neck of the woods you have a place to plug in and relax my friend. Mike

[@ScannerDanner]

Right? It couldn't have been a more convenient place. Thanks again for all the help my friend.

[@ScannerDanner]

hope you saw a bump in your channel subs too

[@AP9311]

Super high quality content! I enjoyed every thing you explained. Increased my understanding how to do a/c systems. Unfortunately i have cheap ass gage set lol. I know most people cheap out on gages when do their ac lol! I'm trying to increase my knowledge on electronical and ac field! I'm trying to absorb your teachings as much i can!

[@rubenceballos2632]

Great explanation. You ran down the whole system basically. You helped me. Thank you.

[@throttlebottle5906]

if there's calibration screws, it will be a flathead screw behind the "white dots/plugs" on the gauge lens, visible about 17:58 many of the cheap gauges don't have holes and plugs in the lens though. also, setting to the zero may not make them right anywhere else, but they're probably not right anyway lol.

[@jimkillen1065]

Sir I appreciate your videos . Where I use to work at a power plant , I was in maintenance and operated equipment . When AC got to not cooling proper in a D11 we called cat out to fix the problem . I think they charged the system to a bit over 300 with nitrogen . Definitely found the leak , Thanks for the information and the time you spent doing this

[@deonpotgieter4473]

I bet they created some more leaks aswell

[@ScannerDanner]

@@deonpotgieter4473 nah, 300 psi is fine. The high side of an AC system will hit those pressures on it's own

[@markraday8071]

Great content you explained everything about the procedure perfectly! I will be watching your channel from now on 💯

[@ScannerDanner]

Thanks Mark!

[@PhillyDee215]

Summer is here🔥I've changed about seven a/c condensors in the last week🥶

[@scientist100]

so far leaky lines for me. One did not have an o-ring washer at the condenser for some odd reason. Perhaps front bumper work that required the condenser to be replaced and didn't install the washer lol

[@djamelabedennacerchiba3233]

Francly . I am always running when the other talk about the ac system . It seems so difficult Today i will learn some thing about that . As you are teaching . Thanks indeed. I must first of all understand how it works . Then iwill understand leaks .

[@johnaclark1]

I installed a simple ball valve on my yellow hose on my gauge set. It allows me to seal the hose when removed but be able to open it when needed. Picking up a used Robinair 34788 machine on Craigslist last year has changed my life, however. It paid for itself half way through the first summer I had it. Your gauge set has small white plugs on the front lenses that pop out and allow you to adjust the calibration with a small screwdriver.

[@danielwoods5605]

Everyone witnessed Scanner Danner pull a rookie move. That O ring only respects your bare hands

[@edwardjaniszewski9389]

Paul that plug on the face of your gauge is access to a calibration screw

[@throttlebottle5906]

some of the cheap gauges don't actually have a plug and just a white dot on the lens where it should be!

[@luismarty1685]

Thank you Caleb.

[@MichaelS-ox2xw]

Hate to be the guy ever having to replace those a/c lines through the cab hey haha.... Great video Danner. Cool to see the system filled another way and using gauges rather than the usual a/c machine trolley.

[@htownblue11]

Paul and crew go on one camping trip in Florida and sleep in the heat and priority numero uno when he gets home is to get the RV AC squared away….hahahaha….I kid I kid. Great break down as usual. Finding the leak Could have been a nightmare with the length of runs those lines have. Your boy giving you crap when you dropped the o ring was hilarious.

[@ScannerDanner]

lol, Caleb and I have grown so close together though all of this. I'm blessed some of you get to see it.

[@JD-526]

I purchased a A/C Manifold Gauge Set ITEM # 60806 from Harbor Freight and a Valve for the small self sealing cans at Advanced Auto. They both worked well together. I did not need the adapter from the self sealing valve to the service hose of the manifold set. Also when measuring temperatures from vents turn the fan down low to get an accurate measurement of temperature otherwise the high-speed of the fan will raise the exiting temperature.

[@2005Pilot]

Kool Infrared camera!! Going to be using the HS to System transfer next go round!! Thanks again, Bro really enjoyed 😊👍👍

[@2005Pilot]

But!!!!! Not a Good Idea if you don’t have check valve as you stressed. I rethought my situation since I’m without a check valve on service hose

[@vbtr01]

Good AC video! You can "measure" the vacuum by the sound of the vacuum pump, close the valves with the pump on it should run very quiet, than open the valves and if pump become noisy, vacuum isn't enough... I have cheap gauges too :)

You have a calibration screw under the rubber things on the glass. I think not sure about those gauges but I do see the rubber plug in the front

[@christophervanzetta]

That thermal imaging camera is great for finding shorts on boards using voltage injection

[@SA-iw4ci]

Hey man. I dig the early to mid 90's GM underhood retractable light you have there. I installed one in my 04 Frontier.👍👍

[@ScannerDanner]

funny, I always forget that light is there lol

[@chrisland169]

yes white plugs in front of gages ,and you need to run the engine at 1500 rpm to see the real pressure so more can Paul!

[@JimmyMakingitwork]

Uh oh, never heard the pressure wasn’t real at other engine speeds? ;)

[@chriscrusader5412]

I think you can adjust your gauges! Look at front of gauge looks like there's a white plug on front, pop that out should be a screw to adjust them back to zero! I read that change in altitude will change them so you have to adjust them. Take care and God bless you and your family!!! You do some awesome videos my friend! You and Caleb are awesome dudes, but your Brother is the most awesome.

[@AdrianKingsleyHughes]

I’m not going to give you crap about the gauges, I just find it hilarious to hear you complain about cheap-ass tools!

[@Goldwing1500rider]

HIM being instructor buying cheap ass gauges?? 🤣😂😅😂🤣

[@Milkmans_Son]

@@Goldwing1500rider An expensive gauge set used once or twice every other year is just as stupid. Besides, what kind of salary do you think HE, being an instructor, makes every year?

[@ahmadghosheh3104]

Did that yesterday on my 2007 Camry Hybrid, need special oil. But yeah, it's intimidating but not hard. The worst part is remembering which valve is open and which is closed 😂. The hot water idea is awesome. On my 2009 Camry the low side is 1.5 inches from the very hot exhaust manifold, yeah, this will help

[@Everyday_Richard]

Paul, remove the little white plug on your manifold set. The clear front plastic piece. Turn the screw. It will realign your needle on zero. Can be done on both high and low pressure guages.

[@robertpope3619]

I'd say Mike might be spot on. The commercial trucks I work on that are sleeper units use that amount.

[@throttlebottle5906]

when you dropped the o-ring, I thought "chances of finding that are slim to none", then you said it. lol

[@LynxStarAuto]

I just saw the Jeep series, and now coming to this getting a good chuckle at the gauge comments. 😂

[@ScannerDanner]

nice!

[@luismarty1685]

You the man Paul! Always love your videos.

[@anthonysova7117]

Good call on the nitrogen I wanted to make a 2cent comment on your previous vid but you got enough comments about checking with air Paul 2 things to remember hot goes to cold and hi pressure goes to low pressure NEXT level in your diagnosis will be checking sub cooling and superheat I’m a retired refrigeration tech checking temperature on systems is easy no more thermistor wrapping on clean copper CHEERS still get thru ur book AMAZING

[@kennethdandurand3472]

At 18:10, there is an adjustment screw on your gauges.....pop the plastic seal above the screw....

[@ganeshnarayan5505]

Great video Mr Danner thanks for sharing.

[@mikep780]

you should check out the power probe temp kit, you can see your ambient temps and utilize two vent temp probes to see what your temps are while charging.

[@johnrockett6495]

Great great job scanner Dan Thank you for teaching me that

[@Pablo_Automotive]

Thanks a lot again Paul your videos are always perfect

[@theadmiral5425]

Nice easy fix for you this time.....If that were my coach I think i would have tried the charging the system using the sub-cooling method like they do in HVAC. That's assuming it has a TXV and not an orifice tube. Eliminates the need to guess on the amount of refrigerant.

[@johnmiley458]

Great informational video.

[@blake8297]

Gotta remember, a micron gauge would be nice, but you can only apply, at best, 14.7 psi of pressure when pulling a vacuum.... It may not be enough to show a leak, but 250psi of nitrogen will be. Ive had orings not leak under vacuum, then leak when I added pressure. I think you said it backwards at 35:30. The gauge was reading 4psi high, so the actual pressures would be lower than its reading.

[@gaad7938]

When you used the blue hose to suck in oil, you also sucked in outside air between the time you unscrewed from valve block and stuck end into oil. Same when oil was all sucked in.

[@ScannerDanner]

And that is why this method is done at the beginning of the evac process

[@PaulWattsSpringGunning]

Great Video. Thanks for the upload! I like to replace the schrader valves when doing a/c work. Nothing is worse than having one leak right after a fill. :-(

[@ScannerDanner]

some of these valves are not easily replaced, so I try to not touch them unless I have to

[@TonyRule]

11:44 Oh, yes it does. Shim change on the clutch just because the gap is a little large.

[@throttlebottle5906]

some didn't have shims and had to be pressed on at the exact right depth to adjust clutch air-gap. of course those ones were deemed non-repairable, because it took an act of god to get them apart and back together without damaging them or wiping front shaft seal out. lol

[@johnaclark1]

A trick I used for charging with small cans was to do the math on how many cans I needed. If I needed, say 28 oz of refrigerant I'd use 4 oz from a partial can and weigh it in first with a kitchen scale. That will go in easy peasy. Then turn that can off and set it aside for another job (have more than one can tap.) Then you can just add the number of full cans you need using the hot water bucket method, can upside down, without having to worry about weighing it in. Most every time I used hot water I was always able to get the full charge in without even starting the engine.

[@scientist100]

Does the hot water allow for a higher pressure and leave the can without the compressor pulling it in?

[@johnaclark1]

@@scientist100 Yes.

[@scientist100]

@@johnaclark1 one would think that the pressure left in the can would mean gas refrigerant until it cools down. Perhaps that's not true, how can the compressed freon not be some sort of left over when it decompresses? What is the freon replaced in volume in this case? Perhaps very little left over? Sorry but this doesn't make much sense to me, I always saw the compressor as a vacuum pump which made sense that the full freon was pulled from the can.

[@johnaclark1]

@@scientist100 Yes, there's always a small amount of gas pressure left in the can but, by weight, it's virtually nothing. Even if you use the compressor to suck the refrigerant in there is still a small amount of vapor left in the can, depending on the low side pressure created by the compressor. It's definitely not a vacuum. If the low side pressure is 40psi with the compressor running then you'll still have 40psi of gas pressure left in the empty can. If you're using the hot water method, yes, you'll have a little more.

[@ScannerDanner]

@@johnaclark1 perfect reply, thank you John. Agree, compressor running, you will still have about 30 psi in the can "leftover" vapor psi. You will NOT be able to remove ALL of the gas in a small can, no matter how you choose to charge the system. By heating the can, you will get the most out, with the compressor running of course, to lower your low side psi, but it is so minuscule in comparison to what I did.

[@lawrenceheinz2679]

Awesome video. Very well explained too

[@rickl6697]

Our 2003 Newmar DSDP had stopped cooling in July of 2018. We took our coach to the Freightliner service center in Gaffney, S.C. to have a M3 service done and get the A/C leak fixed. They found a leaky fitting on a hose at the condenser in front of the side radiator and replace it and charged the system and it worked great for about a year and 2 months then got to where it was no longer cooling. At rest pressure was about 40-50 psi. I bought an electronic leak detector from Harbor freight and checked the fitting and hose they replaced, no leak. All around the compressor and hoses, no leak. Our high and low side ports are at the front of the coach and the low side Schrader valve has a leak the detector could pick up even at 40 psi with the engine off. The high side is fine. Do you know of a device which would allow you to replace a Schrader valve with 40 psi in the system without losing the refrigerate in the system. Too bad they don't have shut off valves behind the Schrader valves. May just have to wait till it all leaks out. Which may take a while. Thanks for posting Paul !

[@ScannerDanner]

what is your ambient temp? 40-50 psi at 80-90 degrees means there is basically nothing in the system anyway

[@rickl6697]

@@ScannerDanner If memory serves me correctly it was 85-90 degrees. We had a trip to Modoc S.C. (Lake Thurmond, Army corp of engerneers campground) planned several weeks ago so I put 2 cans of R134 in And the low side was getting up 55-60 psi running so I'm guessing there is some air in the system. Air temp out the dash was 62 at 1500 rpm and around 68 at idle. Still has a slight leak at the low side chg port Schrader valve.( Was hoping the 134r going in might clear the valve and stop leaking but nope.) Thanks for getting back to me.

[@ScannerDanner]

@@rickl6697 there is some conflicting info here my friend. You said rest psi was 40-50 on an 80-90 degree day. This means your system is basically empty. Then you added two cans and have a low side of 55-60? What was high side psi?

[@rickl6697]

@@ScannerDanner I can't find my little notebook where I wrote the pressures down. To best of my memory the high side was getting up to 135-150 but I couldn't swear to it. I was checking the high side but was focused mostly on watching the low side which was getting high. If Ican find my little pocket notebook I'll post a reply. Thanks for getting back to me. Edit. I still haven't my notebook from 2-3 weeks ago but I did find some video and still pics from Oct 13, 2020. Oct 13, 2020 static was 60/60 Idle. Was. 35/72 (no cooling) High idle. 1100. 22/82(no cooling)

[@ScannerDanner]

@@rickl6697 you need a lot more refrigerant in that system my friend

[@daletuott4545]

Most gauge sets have a screw head toward the bottom center off to one side that you can zero the gauge. Yours looks like it is under the white "dot" on the front "glass". Pull the rubber cover off and remove the bezel and glass to access adjustment screw. If glass is plastic you can drill a small hole to access and put some tape over the hole preventing dirt getting in the hole. The white "dot" maybe a piece of tape coving a hole already.

[@Portuguese-linguica]

Paul that thermo cam . You can use that to check the liquid level in the compressor . There's a KZbinr that does ac units ( can't remember name ) he shows you how to do that .

[@tankabbot22]

Please let Kaleb handle the O-rings next time. His hands are steady as a rock!

[@mattt4183]

I use the argon bottle for my TIG welder for pressure testing. More expensive to fill than nitrogen but I'm not out the cost of another bottle.

[@ScannerDanner]

Are there any concerns using that gas?

[@mattt4183]

@@ScannerDanner It's not theoretically as good as nitrogen for leak detection because it's a slightly larger molecule. No concerns other than that. I don't see any reason why you couldn't use an argon blend, or CO2, MIG shielding gas either. IIRC Bernie Thompson sells a CO2 leak detector for AC systems. One common shop gas you definitely shouldn't use for pressure testing is oxygen. Putting pure O2 into a system containing hydrocarbons is dangerous especially at high pressure.

[@damonzilliox2751]

@@ScannerDanner actually argon would be better than nitrogen because it is a completly inert, noble gas.

[@TimNadaud]

Thanks for the video.

[@pomonabill220]

On your thermal imager (Seek), you need to set the emissivity for what material you are trying to measure for the temperature readout to be accurate. There should be that option to set the emissivity for the shiny plastic versus a matte finish versus human skin versus water, etc. Probably the most overlooked setting on any thermal imager/infrared thermometer (which is fixed on the cheaper units).

[@d.d4184]

Just so your not disappointed. What sort of crap guage are they. 😳Love the hot water trick. Never tough of this.

[@ozzstars_cars]

Have a 'cool' summer Paul.

[@bonzaibarty]

Pop the little caps on the gauge lens and adjust the set screws to zero the needle.

[@TonyRule]

35:07 That is low - you started with the gauge indicating +4 PSIG, not -4 PSIG. So 30 +PSIG indicated is actually only +26 PSIG.

[@ScannerDanner]

LOL my math sucks

[@throttlebottle5906]

his below freezing vent temps agree with it being low on gas and the gauge being off and the engine was idling, so it will be worse when sped up, probably ideal to check around 1500-1800rpm on a diesel engine. R134A at 26psi would be about 24F saturated vapor pressure, which makes for a mighty cold evaporator coil! it will likely ice the evaporator, especially fast if the blower speed gets turned down and maybe just with engine revved. ahh the joys of A/C. for sure needs to calibrate the zero and test the gauges against known good, they could be wrong still even with the zero set right.

[@ScannerDanner]

@@throttlebottle5906 I took a trip already and it was perfect. I don't trust my low side gauge completely either, but I didn't want to add anymore with my high side psi at 225-250 at idle on an 80 degree day. I was more worried about that than the low side showing it to be a little low. But you still may be right, I may be low still.

[@josephwash109]

Those white plugs on the faces of the gauges can be removed to access the zero-adjust screws. You'll just need a small flat blade screwdriver to complete the adjustment.

[@TheCrazy243]

Have you ever service or diagnose 1234yf air conditioning system? I haven’t see any of your videos. I just diagnosed bad AC clutch on 2015 Dodge Durango with 1234yf. Full charge. No leak. I have adapter for it. It was little tricky. Great video tho.

[@kd7cwg]

I did not know about those self sealing cans either. I had to purchase a new tap, because the puncture style does not work on those properly.

[@Mr79elk]

my last set of cheap gauges started leaking past the knobs. while I have some good gauges, I keep cheap ones around, and just replace them every year or two now

[@1kleineMax1]

19:00 The gage probably got damaged while you were putting so much pressure on it. The linear scale stops at 120psi, you went to 250! That may overbend the measuring tubespring inside.

[@jonka1]

I think his mind is too cluttered to think of that. He is right on his limit of ability at times.

[@Jangus]

If the shop air compressor is working correctly, won’t the moisture be removed from the air already?

[@richardcranium5839]

one thing i seen was you burying the low side guage when pressure testing. in my years i've found that guages are like circuit breakers - only normally run them to 80 %. if you bottom out a guage it will stretch the bordon tube inside and the calibration will never be right again. so in that situation i'd put the nitrogen in the high side and watch the low side to make sure it was equalizing showing the expansion valve was working up to about 100 psi the disconnect the low side before upping the pressure. lol at the post on the white plugs for calibration. also you may get away with liquid on the low side being carefull but all it takes is that one time liquid slugging to wish you hadnt. seen it too many times. used to be the recievers all had sight glasses. was great for charging. now you pretty much have to go by pressure and temp if you dont know system volume. theres an electronic tool that checks for bubbles on the liquid side but you need 6 inches of steel or aluminum tubing for it to work correctly and most vehicles dont have that they're all hose.

[@ScannerDanner]

100% spot on comment as to what happened to my gauge. my man

[@The_Redkween]

At 35:15, your offset gauge pressure was offset about +4 psi, so your low-side pressure was actually 4 psi lower than what the gauge showed, not higher. :). Edit: nvm, I see someone else caught it

[@malcolmy11]

Thanks for the video. When you were charging with the engine on, shouldn't you subtract about 5 psi from the gauge reading? Since the busted gauge was showing 5 psi at atmospheric pressure. So your low side pressure was actually 25 psi rather than 45 (gauge needle was at 30). Is my understanding correct?

[@ScannerDanner]

Yep, my math sucks 😄

[@AdrianKingsleyHughes]

Those thermal cameras are fun. They rely on emissivity of a surface. On shiny surfaces I pop a bit of kapton tape which makes the reading more accurate.

[@robertrichardson1133]

I see you just watched the same Motor Age video I watched. Lol

[@AdrianKingsleyHughes]

@@robertrichardson1133 credit where it’s due, I think I got that off the awesome bigclivedotcom! But I’ll have to check out that channel. Thanks!

[@robertrichardson1133]

I think it was to days ago that I watched the video diagnosis with thermal imagery and he used the term emissivity (which I had never heard before) and then used some electrical tape on a A/C line because it was shiny. I haven't seen the video bigclive did on it.

[@GeminiSeven43]

I purchased a Flir TG165 and on heater bands have a hard time getting accurate temps and was wondering about adjusting the emisivity on it. I know from experience with the spot infrared meters it is night and day from one spot to another due to reflectivity and it would be nice to use a piece of tape to even things out. Thanks so much.

[@paulthompson1654]

hi charge by weight ,sight glass , subcool for txv or super heat for ccot .While always looking at high and low pressures . Oh yea crank the engine upto 1200-1500 rpm Check cleanliness of evap core ?? change receiver drier always

[@Turbotomass]

Is the only concern with using compressed air to pressure test moisture? Will pulling a vacuum on the system not remove that moisture? If the vehicle a/c system has a leak I figure there's probably a lot of moisture in the system anyway. I've seen compressed air left in an a/c system destroy an air compressor.

[@ScannerDanner]

To be honest, I've been using compressed air for over 20 years and never, not once, had an issue. I'm just tired of defending it, and I can't argue with moisture free nitrogen being better.

[@LChand]

Hi ScannerDanner, what’s being used these days to replace r134a? As availability in Canada to get r134a is becoming difficult. Thanks for all your great educational and entertaining videos !!

[@ScannerDanner]

A new refrigerant that is actually flammable, kind of crazy. But not sure what is being offered as a retrofit for R134a as we still carry it even at the local Wal-Mart

[@LChand]

@@ScannerDanner was afraid of that, maybe I’ll have to visit a Walmart out there. Thanks for the reply, keep up the great videos!

[@ralfsautomotive]

Why don't you use the screw to adjust the gauge? Under the plastic Plug. Am I missing something?

[@ScannerDanner]

lol, read my pinned comment my friend

[@ralfsautomotive]

@@ScannerDanner LOL go figure!!!

[@thirtythree160]

2:36 Lo side is 100psi and hi side is 80psi. Can the low side gage take 200 to 300 psi without messing the gage up?

[@ScannerDanner]

This particular low side gauge does list 350 as a max, so it shouldn't have tweaked the calibration, but it did.

[@TonyRule]

@@ScannerDanner Actually, there's a bit of video at 12:45 just before you had the N2 hooked up showing the low gauge already sitting at +4 PSI. So unless that's out of sequence, the high pressure wasn't the cause. Edit: Sorry, I forgot, that was the second pressure test. Yeah, you tweaked it with the 250PSI N2 at - see the low pressure gauge at 6:12 - I'm not sure what that 350 refers to.

[@liquidrockaquatics3900]

Question for you. My manifold gauge set does NOT have a check valve in the end of the yellow hose, but it would sure be useful; was that something you added yourself? When using the 12 oz cans an can taps, is the tiny amount of air in the tap detrimental? I have been bleeding back refrigerant from the system to the can with the blue dial and the car running until I can just barely hear gas escaping and then closing the can the last 1/8 thread to get all the atmosphere out. I have been using the old style pierce cans

[@ScannerDanner]

no sir, my yellow hose that came with my manifold gauge set already had the built in check valve. And I would say no, on that tiny amount of air. Nothing to stress about.

[@danielschmidt4762]

On some gauges they have screw on the face of the gauge to adjust it to 0

[@robertgarrett5009]

I do some commercial refrigeration (big ass building chillers), I only ever use my thermal imager, and a set of insert probes for fluid temps. My thermal imager is a Fluke, much better than the unit used here.

[@joeydelmarsjr.646]

fluke are expensive

[@bartscave]

Some equipment service trucks use large nitrogen tanks instead of air compressors for air tools. They’re cheap to refill