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

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.

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

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

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.

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

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.

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.

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!

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👍🇦🇺

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.

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.

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!

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!!

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!

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

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.

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!

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.

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❤

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!❤️

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

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

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

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.

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 .

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.

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 🤣

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

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

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

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

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!

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

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 :)

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.

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!

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

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.

@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.

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

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

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.

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

Thank you Caleb.

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

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.

👏👍 getting better Finding the leaks on those large RVs can be a bit of a pain with a mile of hose. That’s where a combination of using the ultrasonic leak detector when you have it pumped up high with nitrogen comes in the play. And with refrigerant a very sensitive refrigerant leak detector like the D-Tek. Stratus All those old rVs with all that hose naturally loses a little bit of refrigerant right through every foot of hose and when you stack up many feet that adds up to a slightly bigger leak that you cannot pick up using UV dye or looking for signs of oil and sometimes unless really bad not even the leak detector picks it up because it’s diluted down so much per foot of hose. As for the thermal imager or the infrared thermometer. When you point those optical devices directly into the cold air stream it rapidly chills the lens distorting the optical refraction of the infrared and start showing a much colder false reading than is actually really there. So you will get a cold reading that keeps falling to a crazy cold point that’s almost not possible unless you really had a true mechanical thermometer that was accurate telling you to real temperature. So what it comes down to , thermal cameras or imagers thermal infrared thermometers do not allow the cold airstream to directly blow onto the face of the thermal imager. As for a high-pressure nitrogen leak Decay test. That’s where a extremely accurate digital pressure read out that has the decimal point and reads down to 1/10 of a psi is very helpful. But before hitting the leak decay test button allow the system to stabilize after adding high pressure for about 10 minutes if there’s no obvious big leak then hit the button and ststart yourocked in timer countdown. The Fieldpiece SM480V refrigerant manifold is an excellent tool for this job. You mentioned a micron gauge they are extremely useful. But it takes a learning curve and it could be very frustrating learning how to use one correctly and understanding what they mean by the numbers. AccUTools BluVac+Pro Micron gauge is one of the best steadiest most reliable and more forgiving about getting oil contamination up in the sensor. And often when searching for leaks many times you can draw a vacuum and have zero leaks because the negative pressure actually pulls in the rubber up tight and seals to itself or up against a metal surface with a thin film of oil and performs a perfect airtight seal. But when adding pressure in reverse the rubber expands and folds out and opens up and then will leak under pressure where it did not leak under vacuum. Situation with RVs where they’re usually sitting for many months of the year and are never in any hurry to go anywhere unless they’re taking off on a vacation I might swing by the customers jobsite pump it up with 150 or 175 psi of dry nitrogen and then leave and come back 24 hours later if I left my gauges there or disconnect my gauges and come back in one or two weeks if it’s a very very small leak after I have done my repairs to prove my repairs were the only leak. And then recharge the system with refrigerant. And that’s when you discover you might have one of those leaks that are sensitive to temperature as the metal and rubber expand and contract and all your leak testing found nothing and it started leaking instantly blowing out refrigerant once the metal or rubber has contracted and spilling out refrigerant rapidly. Then there’s those leaks that only leak under vibration when the vehicle is moving down the road and hoses and fittings are bouncing and vibrating then they start leaking when pulled in stopped in a garage stagnant steady but running the leak stops those can be tough the phone usually UV dye will find those ones.

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

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

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.

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

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

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

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.

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.

You the man Paul! Always love your videos.

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).

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.

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

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

Great informational video.

Thanks a lot again Paul your videos are always perfect

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.

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

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.

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.

1. your gauge started at 4 psi, so 30 minus 4 = 26 psi pressure {not add to for 34 psi}. 2. hook up at compressor gives lower reading than if hooked in line further away from the compressor. 3. diesels idle slower rpm than gas, giving higher low side reading. Less suck at low RPM. I think you're low on charge. I would idle up to 1200-1500 rpm, add gas till I hit at least 30 psi with your gauges giving at least 26 psi actual in case it has a low pressure switch that usually cuts ac off 20-25 psi. Then drive it and see how it does. MIGHT STILL NEED MORE. YOU'LL KNOW ON THE FIRST HOT DAY OF YOUR NEXT TRIP....Hope this makes sense and helps.

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

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.

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.

Great video Mr Danner thanks for sharing.

Take the cover off the back of gauge. If you see an oval cross section brass tube shaped as a 'C' that is attached to gears which move the dial pointer, you can very gently bend the tube into a larger or smaller curve to "recalibrate".

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

Always check for leaks under pressure (not in a vacuum) ....because that's the way the system operates and you can seal leaks up in a vacuum.

Two things about those gauges you have a little tiny plug or the screws out you pop it out. Use the screwdriver to adjust it or you pop the whole lens off you don’t go from the back side you don’t do it every day don’t mess with the gauges let somebody that knows what they’re doing mess with them because you don’t.

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.

Careful(just careful) putting to much pressure into the system when trying to find a leak. Wait for it.............................................................LOL I had that bite me before! No, NO not cause I was overpressuring the system, I can hear people screaming LOL but because the seal that was actually leaking sealed under the higher pressure. Since then I test in stages and use vacuum testing more often.

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.

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. :-(

Great great job scanner Dan Thank you for teaching me that

never aim the bottom of the can at yourself or anyone, because that's where it will bell outward and split open venting everything from over-pressure. this goes with your warning about not opening the high side with vehicle running, the bottom splitting open is exactly what should happen, vs. the top or whole bottom coming off.

I live in a trailer. That damn rv is more advanced the my house!! Crazy and cost 3 times more my house was 32k brand new!!

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

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.

Thanks for the video.

To calibrate those cheap gauges, you pull the little white plug on the sight glass, then use a small screw driver on the screw in the gauge face.

35 year's of working on a/c system's I can tell you you are write on the money with with that a/c pressure .

Awesome video. Very well explained too

The gauges are adjustable as far as the zero point. Those little white inserts on the face should be removable and the brass screw will allow you to re set to zero indication. Calibrating for accuracy is more complicated and requires more instrumentation.

You rock bro !! Thank you

Nice job, Thank you.

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

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

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

When I first moved to the ac department at my shop I pulled the gauges off without sucking the high side down. Without doing that I didn’t know that the valve on the high side was stuck open. That was not a fun day.

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

I have a microwave oven in my shop, so i use it to heat the water up to put the cans of refrigerate in.

Back in the 90’s when they banned r12 people were using propane to charge ac systems.

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.

You have to remove the small round plastic plug at the lower center of the guage face and with a small flat tip screwdriver insert it through the hole and turn the small screw to zero out the guage needle.