Thinking about buying an AC recovery machine

[Wrench97]

Yeah thats pretty much what I posted in OP except it was a larger model with self purge. I'm sure it would work but not actually approved equipment for automotive (per EPA).

Yea they want us to fight the front seal leak under vacuum issue(pressure pushes it out to seal) that doesn't exist on sealed units.

 

[cgrutt]

Nope not yet but as luck would have it my compressor blew up on me last week on my F150... should never have mentioned I was thinking about servicing it haha. Pretty sure its just the clutch and I may be able to repair it without evacuating the system. Issue is $$$ at the moment I would love to get the recovery unit but got sidetracked on my boat.

Pretty sure compressor is OK (it was working fine before it stopped last week). Not seized up. Still has refrigerant. I removed clutch and pulley and the clutch was in bad shape. Rubber in-between the outter shell and inner plate was completely blown apart and it was no longer attached. The face was also in rough shape had two pronounced grooves with matching grooves on the pulley. The bearing in pulley was still in tact but felt a little gritty. I was going to just order a clutch and bearing but thought it would be best to replace entire pulley due to the grooves on face. Looked at aftermarket kits but wasn't sure if they were identical and would work with the oem magnetic coil. Also most of the reviews were mixed some good some bad. Anyway just ordered the OEM Motorcraft parts. Should have them on Tuesday.

Oh, is there a tool that holds clutch in place while bolt is being loosened/tightened? Tried oil filter wrench which probably would have worked if compressor was off vehicle but I left it attached and didn't have much room. Wound up using a prybar which worked but clutch was already shot don't want to do that with the new part. There's no holes or anything where a spanner would fit.

 

[Wrench97]

This is the most common one.

But I know there are a couple I've had to use a strap wrench on.

 

[cgrutt]

This is the most common one.

But I know there are a couple I've had to use a strap wrench on.

Yeah I know about that style but there are no holes to put the pins in. Strap wrench may work thanks.

 

[cgrutt]

This is style that is on my truck. I wish I had the flip up fan shroud that would have made access a bit easier. Mine just blew up I didn't have the loud squealing that's on video. I also bought a smaller belt and replaced an idler pulley with a ribbed style and rerouted belt bypassing compressor because I was afraid it might have seized up on me before I had a chance to repair it. My pulley has no friction material left on it as shown on the video glad I ordered a new one. Apparently just use a small impact to get the clutch off I should have tried that but just used a ratchet. Anyway good video if anyone finds themselves in same predicament with 2004-2008 Ford.

 

[Carchie]

expensive to do this for just 3 jobs in your life. By the time you get to the 4th, the refrigerants, fittings and laws will have changed again. It may be less costly to pay a shop you trust to pull the system down, do the repair yourself, and then have them recharge the system in part with the refrigerant they reclaimed. Gone are the days of inexpensive vacuum pumps, inexpensive canisters of refrigerants, etc.. Might look on FB Marketplace for a good working system that was used on the type refrigerant you want to service. Also Vevor has a 3/4 HP unit for $373, 1hp for $477, and new recovery tanks for $76.

Spot on. The cost of DIY recovery gear for just a couple of jobs rarely makes sense anymore, especially with environmental rules changing so fast.

 

[75gmck25]

I'm considering a recovery of the R134a from my '75 GMC pickup so that I can check out the old evaporator for leaks (original; might have a small leak), replace the orifice and accumulator, check hose connections, and then do a complete recharge. I may also make new hoses, in an attempt to improve the routing and make it easier to work on the engine. The A/C is currently working, but has gradually lost some charge over the last couple of years, so its cooling is not very effective.

If I buy a recovery machine and tank, what do you do with the R134a that is recovered? Is there somewhere you take it for disposal, or is the assumption that you could filter it and use it to refill the system?

FYI - I live in Northern Virginia, where its difficult to find a small shop that has experienced mechanics and wants to bother with working on an old A/C system. They have plenty of business from newer vehicles where they can hook up an automated machine and let it do all the work.

 

[cgrutt]

I'm considering a recovery of the R134a from my '75 GMC pickup so that I can check out the old evaporator for leaks (original; might have a small leak), replace the orifice and accumulator, check hose connections, and then do a complete recharge. I may also make new hoses, in an attempt to improve the routing and make it easier to work on the engine. The A/C is currently working, but has gradually lost some charge over the last couple of years, so its cooling is not very effective.

If I buy a recovery machine and tank, what do you do with the R134a that is recovered? Is there somewhere you take it for disposal, or is the assumption that you could filter it and use it to refill the system?

FYI - I live in Northern Virginia, where its difficult to find a small shop that has experienced mechanics and wants to bother with working on an old A/C system. They have plenty of business from newer vehicles where they can hook up an automated machine and let it do all the work.

If recovery unit has filter and dryer believe you can reuse the recovered refrigerant in your system.

 

[Wrench97]

If recovery unit has filter and dryer believe you can reuse the recovered refrigerant in your system.

Yes you recover for reuse. Contaminated refrigerant needs to go to a reclaimer like Agas in a DOT certified bottle, most HVAC supply houses can also take it some will buy it others will charge you to take it.

 

[joel63]

Do the job yourself and know that its done right has always been very high on my list of personal priorities. I enjoy learning new things and having ability to repair stuff for both myself as well as friends and family. And of course there's the tools... not so much having a collection but more being able to handle projects when I need to. Let's just say have a very strong preference for self reliance.

To me, that's what it's all about. Something that I've subscribed to in my time.

 

[cgrutt]

Well just ordered a Mastercool 69100 Amazon had 30% off coupon got it for $981 (before tax). Still need to order some more stuff (scale, micron gauge, etc) but I've been thinking about this for a while now and price was right.

 

[cgrutt]

Well scratch that its the wrong model number (not certified for automotive) I just canceled it.

Turns out it actually is approved by EPA for automotive but doesn't include some accessories that are in the 69110 kit. I may reorder...

 

[aggie113]

if you are hoping to dispose of old refrigerant properly, be sure a local gas recycler will take stuff from regular folks.

 

[cgrutt]

So apparently the difference between 69100 and 69110 is the 69110 is explicitly marketed for automotive and includes high side hose and quick connect. Both use same pump and compressor. I checked EPA site and both models are approved for automotive. I reordered and added the high side hose and connector (plus a tee adapter) so its basically the same.

 

[cgrutt]

if you are hoping to dispose of old refrigerant properly, be sure a local gas recycler will take stuff from regular folks.

Hoping to reuse the recovered refrigerant after I replace compressor.

 

[cgrutt]

Ordered a compressor (kit including expansion valve and receiver dryer / accumulator) and new serpentine belt for wife's car today.

Also ordered a new manifold, set of hoses, micron gauge and a refrigerant scale. Should be pretty much set as far as equipment goes.

Got home early today and the local Airgas store was actually open so decided to stop in. Picked up a small tank of Nitrogen and a purge regulator. Kinda surprised how much that cost but figured I'd use it to purge and pressure test system. They sold me a Snith 30-450-580 regulator for the Nitrogen. Balked at the price but it seems like pretty good quality.. Body appears to be brass.

 

[Snapped-off]

These are pretty nice recovery machines. Very fast.

 

[cgrutt]

Nitrogen purge after refrigerant recovery before opening system to change components to prevent atmospheric air (and humidity) from being sucked into system when opened. Seems like a smart move.

 

[pcmeiners]

These are pretty nice recovery machines. Very fast

How much was this unit?

 

[Snapped-off]

How much was this unit?

$10k.

 

[cgrutt]

Started working on wife's car today. The recovery machine seems to work pretty good recovered 1.94 lbs out of 2.1 to 2.17 lbs capacity. The expansion valve was a PITA due to location but I got that changed.

Nitrogen purge seems to work good but I had pressurized system with about 4 psi after recovery. Small burst of pressure sprayed a bunch of PAG oil over firewall and my hand when I disconnected the hose going into expansion valve. Wasn't expecting that haha.

Used the micron gauge to prep recovery tank. That worked good. Used the manifold during recovery to draw from both high side and low side. Didn't get any oil out of recovery machine. I'll dump it out of compressor when I pull it out tomorrow and see how much was in it. Looking for about 4 oz.

 

[cgrutt]

Well got the Mercedes sorted out turned out to be a difficult project but finally got it back together. It completely resolved the main issue with noise that has probably been going on for past ten years! Car sounds new again. Had a bunch of issues getting it to pull and hold a vacuum I wound up buying another new expansion valve and got it sorted out. I believe I had that in and out three separate times trying to track down a very small vacuum leak. Was only able to pull system down to 580 microns but close enough. It stabilized and held at about 800 before I charged system. Charging was also an issue. Wound up using 12 oz cans and a hair drier to create a pressure differential. Weighed out 2.17 lbs which is the exact spec but suspect I'm a little under (but probably within spec 2.1 lbs + 0.07 lbs) that with minor loss in lines etc. Had center register reading 44 F it was very cold and fresh feeling on a warm muggy night.

We're heading upstate tomorrow morning (should have left today but have major issue with my truck... ugh) so had to get the car back together for the holiday weekend. More on the truck and other projects I have lined up for the Mercedes next week. Very happy with the new equipment little bit of a learning curve but it all seems to work great.

 

[Wrench97]

Getting a low micron reading on a automotive system is impossible, the front seal of the compressor is designed to hold pressure in, when placed under a vacuum they will leak. One of the reasons you have sealed compressors in HVACR.

 

[cgrutt]

Getting a low micron reading on a automotive system is impossible, the front seal of the compressor is designed to hold pressure in, when placed under a vacuum they will leak. One of the reasons you have sealed compressors in HVACR.

I was running into that very frustrating! Had vacuum down into 700s thinking all was good then it would suddenly spike well into 1000s come down a bit but never recover. Pressurize with nitrogen to 150 psi and it seemed leak free. I suspected o ring collapsed under vacuum but held tight under pressure but also wasn't quite sure if it was with my equipment or not. I think in my case it was expansion valve it had four different size o rings and may have mixed up which one went where. Overall quite the learning experience!

 

[Wrench97]

I was running into that very frustrating! Had vacuum down into 700s thinking all was good then it would suddenly spike well into 1000s come down a bit but never recover. Pressurize with nitrogen to 150 psi and it seemed leak free. I suspected o ring collapsed under vacuum but held tight under pressure but also wasn't quite sure if it was with my equipment or not. I think in my case it was expansion valve it had four different size o rings and may have mixed up which one went where. Overall quite the learning experience!

Na the compressor seal is a lip seal similar to a wheel seal it will get so low then burp, don't fret it that's why the receiver/dryer/accumulator has a bag of desiccant in it.

 

[cgrutt]

Na the compressor seal is a lip seal similar to a wheel seal it will get so low then burp, don't fret it that's why the receiver/dryer/accumulator has a bag of desiccant in it.

Believe the issue I was struggling with was definitely the expansion valve not being seated 100% it resolved after I swapped it for a 2nd brand new one. It was only on vacuum held pressure fine.

 

[mm08822]

Well got the Mercedes sorted out turned out to be a difficult project but finally got it back together. It completely resolved the main issue with noise that has probably been going on for past ten years! Car sounds new again. Had a bunch of issues getting it to pull and hold a vacuum I wound up buying another new expansion valve and got it sorted out. I believe I had that in and out three separate times trying to track down a very small vacuum leak. Was only able to pull system down to 580 microns but close enough. It stabilized and held at about 800 before I charged system. Charging was also an issue. Wound up using 12 oz cans and a hair drier to create a pressure differential. Weighed out 2.17 lbs which is the exact spec but suspect I'm a little under (but probably within spec 2.1 lbs + 0.07 lbs) that with minor loss in lines etc. Had center register reading 44 F it was very cold and fresh feeling on a warm muggy night.

We're heading upstate tomorrow morning (should have left today but have major issue with my truck... ugh) so had to get the car back together for the holiday weekend. More on the truck and other projects I have lined up for the Mercedes next week. Very happy with the new equipment little bit of a learning curve but it all seems to work great.

That's awesome!! 4 months ago (almost) everyone was saying not to purchase equipment and here you are now having fun.

 

[signcrafter]

Started working on wife's car today. The recovery machine seems to work pretty good recovered 1.94 lbs out of 2.1 to 2.17 lbs capacity. The expansion valve was a PITA due to location but I got that changed.

Nitrogen purge seems to work good but I had pressurized system with about 4 psi after recovery. Small burst of pressure sprayed a bunch of PAG oil over firewall and my hand when I disconnected the hose going into expansion valve. Wasn't expecting that haha.

Used the micron gauge to prep recovery tank. That worked good. Used the manifold during recovery to draw from both high side and low side. Didn't get any oil out of recovery machine. I'll dump it out of compressor when I pull it out tomorrow and see how much was in it. Looking for about 4 oz.

Couldn't you reuse the 134 you recovered, or does your recovery machine not do that? You said you charged from 12oz cans. If I spend that much on equipment I would want to be able to reuse the refrigerant when I recover it.

Curious the cost of your nitrogen and regulator if you feel like sharing it or PMing me it. I've been thinking about getting nitrogen also. I've never seen anyone purge with nitrogen after recovering a system. When you unhooked your lines were you able to plug them right away before the system lost the nitrogen pressure? I get his theory of not letting air in but usually you are opening up the system and exposing it to air when doing repairs. Not always possible to plug things and keep the system pressurized when doing repairs. Most common repair I do is for a compressor that died so I replace the compressor, condenser, expansion valve, and dryer and flush the lines and evaporator the best I can. Pretty hard to keep the system pressurized when doing that unless you were to replace one part at a time and plug the rest of the system to keep it pressurized. I'm not an expert but thought that purging with nitrogen after opening the system and doing the repairs and then pulling a vacuum to boil any air and moisture out was acceptable. Think most shops even skip the nitrogen purging from what I have seen and just pull a vacuum after repairs before charging.

Glad the equipment you bought worked out for you. I'm still thinking about what all I want to get or which direction I want to go. Will your setup also work for 1234yf if you buy another recovery tank?

What micron gauge did you go with?

 

[cgrutt]

I decided to use fresh cans believe it was only $45 at NAPA so just bought them and went that route instead. I still have the recovered refrigerant and will probably use it on a future project.

I don't have exact cost of nitrogen but want to say about $500. I bought it at a local welding supply so am sure I paid more than I could have found it for online but I own the tank and believe regulator is actually a pretty good one. I wound up using it more than I expected chasing the small leak so very glad I bought it. When I initially opened system there was only a small positive pressure and I placed rubber plugs in ends of all lines but the nitrogen was gone as soon as I opened system. From what I understand (and I'm a complete nube at this) the theory is you just don't want the vacuum from recovery sucking ambient air back into system when you open it so nitrogen creates a small positive pressure instead of a vacuum. Either way I found it far more useful for checking for leaks and glad I had it. I originally had a leak at drier and wound up using slightly thicker orings than what came with new drier to fix that issue. That was easy to track down with the nitrogen.

The micron gauge is the BluVac+ Pro seems awesome and I was actually using the app to track vacuum. It is so sensitive I probably wouldn't even known I had a problem with expansion valve without it. As a side note I also found out my Harbor Freight manifold is junk and won't hold a deep vacuum by itself let alone connected to vehicle. I was having so many problems chasing the microscopic leak I switched manifolds to make sure problem wasn't the new manifold. The small leak immediately turned into a massive one (at the micron level) with Harbor Freight manifold connected haha.

 

[cgrutt]

Oh just thought about something else not sure if it is issue with all cars or not but turns out I needed a scan tool to clear low pressure code (in the ac system not a standard obdii code) triggered by Mercedes system that prevented new compressor from working immediately after charging system. The ac light in vehicle was flashing and compressor didn't seem to work at first. Checked with my Autel and sure enough there was a trouble code that had to be cleared before compressor would start. Wasn't expecting that.

 

[Wrench97]

Oh just thought about something else not sure if it is issue with all cars or not but turns out I needed a scan tool to clear low pressure code (in the ac system not a standard obdii code) triggered by Mercedes system that prevented new compressor from working immediately after charging system. The ac light in vehicle was flashing and compressor didn't seem to work at first. Checked with my Autel and sure enough there was a trouble code that had to be cleared before compressor would start. Wasn't expecting that.

That's mostly a Benz thing most others will activate the compressor once the switch shows pressure.
Volvo trucks would not turn the compressor on if the outside air temp sensor read below 32f however if you unplugged the sensor the dash would read -41 and A/C compressor would work just one of their many quarks.

 

[signcrafter]

I decided to use fresh cans believe it was only $45 at NAPA so just bought them and went that route instead. I still have the recovered refrigerant and will probably use it on a future project.

I don't have exact cost of nitrogen but want to say about $500. I bought it at a local welding supply so am sure I paid more than I could have found it for online but I own the tank and believe regulator is actually a pretty good one. I wound up using it more than I expected chasing the small leak so very glad I bought it. When I initially opened system there was only a small positive pressure and I placed rubber plugs in ends of all lines but the nitrogen was gone as soon as I opened system. From what I understand (and I'm a complete nube at this) the theory is you just don't want the vacuum from recovery sucking ambient air back into system when you open it so nitrogen creates a small positive pressure instead of a vacuum. Either way I found it far more useful for checking for leaks and glad I had it. I originally had a leak at drier and wound up using slightly thicker orings than what came with new drier to fix that issue. That was easy to track down with the nitrogen.

The micron gauge is the BluVac+ Pro seems awesome and I was actually using the app to track vacuum. It is so sensitive I probably wouldn't even known I had a problem with expansion valve without it. As a side note I also found out my Harbor Freight manifold is junk and won't hold a deep vacuum by itself let alone connected to vehicle. I was having so many problems chasing the microscopic leak I switched manifolds to make sure problem wasn't the new manifold. The small leak immediately turned into a massive one (at the micron level) with Harbor Freight manifold connected haha.

It makes sense to purge with nitrogen after recovering so you don't "vacuum" air in when opening the system. But think trying to keep the system under pressure while working on it so no air gets in is pretty hard and don't think many if any do that. I understand air has moisture and not good for the system. But I'm not a pro and don't know the exact science so not sure how much more moisture would get into the system if you open a system that has been vacuumed down vs opening one that was pressurized with nitrogen? Also not smart enough to know the physics(think that's the term) of how vacuuming the system down after repair to boil the moisture out would be affected by opening the system under vaccum vs opening it while under pressure of nitrogen. Would love to learn from someone on here smarter then me.

I guess I just don't see being able to keep the system pressurized while doing repairs like the guy in your video said very realistic. You said you lost all pressure as soon as you opened up the system so atmospheric air then entered the system. Wondering how much worse air being sucked in when opening system that's under a vacuum is then allowing air to enter a system with no vacuum on it would be? Maybe it does create a lot more moisture entering but I don't know. Also then how that would affect the vacuuming during refilling being able to get the air out of the system?

I'm not being argumentative, genuinely would like to know and learn. But if you are going to open the system up and allow air in either way, and if vacuuming it down after will get it out then I guess I don't see the point to purging with nitrogen before opening the system. The guy in your video was saying to keep the system under pressure the whole time doing the repair so no air could get in.

I don't have experience with recovery machines but think they only remove the oil that is mixed with the liquid refrigerant on the high side and leave the majority of the oil in the system. So having some spray out when you opened your pressurized system would be normal I would think. When I replace a compressor or condenser or whatever the car usually comes to me pretty much empty. I will look up service info and they list how much oil you should add when you replace each part. Think it's more of a guideline but I figure it's the best I can do. And if I'm replacing the compressor, condenser, and dryer then I flush the evaporator and lines which should get most of the oil out of them. So I will add the recommended amount of oil for the whole system. Not sure if there is a better way to do it or not. You can drain the compressor and measure how much comes out but not sure you can accurately do that to a condenser and other parts.

Are you going to look into getting a 30 pound tank instead of little cans if you are going to put new refrigerant in instead of reusing the old stuff? You would save some money over buying 12 ounce cans but they are just way easier to use and measure. But they are another big upfront cost when buying all the tools you did. I haven't looked up prices lately but think last time I did it was almost half the cost of buying little cans.

Again, I'm not arguing or debating anything. Just typing what I know and hoping to learn more or be corrected if I'm wrong. AC work is a whole different skill set with lots of technical stuff and I'm always trying to learn more to do it correctly. I think a lot of auto mechanics learn the basics which is good enough to be able to replace parts and charge the system but there is so much more to it in my opinion. I am not a pro or expert or anywhere close and I started off with a set of gauges and a vacuum pump to replace a compressor on my car many years ago and got by. But have tried to learn more with each repair and get more tools to do it the right way. You jumped all in with the equipment. I couldn't afford that when I replaced my first compressor 20 something years ago. Didn't even know what a micron gauge was back then or much about how an AC system even worked. Learned the basics of how to charge it and didn't have a scale so just guessed the best I could with the little cans. But I'm always trying to learn and better myself.

One thing I've learned and don't recall reading it in your posts is I've found the high and low schrader valves a source of leaks many times so I always replace them whenever I do any work on the system. They are cheap and easy to do so it's just an automatic for me. Depending on the vehicle you need a core removal tool or the special sockets for some.

 

[cgrutt]

It makes sense to purge with nitrogen after recovering so you don't "vacuum" air in when opening the system. But think trying to keep the system under pressure while working on it so no air gets in is pretty hard and don't think many if any do that. I understand air has moisture and not good for the system. But I'm not a pro and don't know the exact science so not sure how much more moisture would get into the system if you open a system that has been vacuumed down vs opening one that was pressurized with nitrogen? Also not smart enough to know the physics(think that's the term) of how vacuuming the system down after repair to boil the moisture out would be affected by opening the system under vaccum vs opening it while under pressure of nitrogen. Would love to learn from someone on here smarter then me.

I guess I just don't see being able to keep the system pressurized while doing repairs like the guy in your video said very realistic. You said you lost all pressure as soon as you opened up the system so atmospheric air then entered the system. Wondering how much worse air being sucked in when opening system that's under a vacuum is then allowing air to enter a system with no vacuum on it would be? Maybe it does create a lot more moisture entering but I don't know. Also then how that would affect the vacuuming during refilling being able to get the air out of the system?

I'm not being argumentative, genuinely would like to know and learn. But if you are going to open the system up and allow air in either way, and if vacuuming it down after will get it out then I guess I don't see the point to purging with nitrogen before opening the system. The guy in your video was saying to keep the system under pressure the whole time doing the repair so no air could get in.

I don't have experience with recovery machines but think they only remove the oil that is mixed with the liquid refrigerant on the high side and leave the majority of the oil in the system. So having some spray out when you opened your pressurized system would be normal I would think. When I replace a compressor or condenser or whatever the car usually comes to me pretty much empty. I will look up service info and they list how much oil you should add when you replace each part. Think it's more of a guideline but I figure it's the best I can do. And if I'm replacing the compressor, condenser, and dryer then I flush the evaporator and lines which should get most of the oil out of them. So I will add the recommended amount of oil for the whole system. Not sure if there is a better way to do it or not. You can drain the compressor and measure how much comes out but not sure you can accurately do that to a condenser and other parts.

Are you going to look into getting a 30 pound tank instead of little cans if you are going to put new refrigerant in instead of reusing the old stuff? You would save some money over buying 12 ounce cans but they are just way easier to use and measure. But they are another big upfront cost when buying all the tools you did. I haven't looked up prices lately but think last time I did it was almost half the cost of buying little cans.

Again, I'm not arguing or debating anything. Just typing what I know and hoping to learn more or be corrected if I'm wrong. AC work is a whole different skill set with lots of technical stuff and I'm always trying to learn more to do it correctly. I think a lot of auto mechanics learn the basics which is good enough to be able to replace parts and charge the system but there is so much more to it in my opinion. I am not a pro or expert or anywhere close and I started off with a set of gauges and a vacuum pump to replace a compressor on my car many years ago and got by. But have tried to learn more with each repair and get more tools to do it the right way. You jumped all in with the equipment. I couldn't afford that when I replaced my first compressor 20 something years ago. Didn't even know what a micron gauge was back then or much about how an AC system even worked. Learned the basics of how to charge it and didn't have a scale so just guessed the best I could with the little cans. But I'm always trying to learn and better myself.

One thing I've learned and don't recall reading it in your posts is I've found the high and low schrader valves a source of leaks many times so I always replace them whenever I do any work on the system. They are cheap and easy to do so it's just an automatic for me. Depending on the vehicle you need a core removal tool or the special sockets for some.

I'm pretty much a tool junkie what can I say haha. Its all good I like to do the best job I can and feel having the right tools is a large part of that. I didn't mean to suggest or intend to keep lines pressurized while doing repair so sorry if it or video I posted came across as such. The takeaway I got from video is if system was under vacuum when you opened it up it could **** ambient air and moisture deep inside components but if you pressurized it before hand it wouldn't allow the moisture to penetrate as deeply thats all. Made sense in my mind and I wanted the nitrogen to pressure test system. I did replace the schrader valves. Believe they are high flow standard valve core tool didn't fit I used needle nose pliers.

 

[signcrafter]

I'm pretty much a tool junkie what can I say haha. Its all good I like to do the best job I can and feel having the right tools is a large part of that. I didn't mean to suggest or intend to keep lines pressurized while doing repair so sorry if it or video I posted came across as such. The takeaway I got from video is if system was under vacuum when you opened it up it could **** ambient air and moisture deep inside components but if you pressurized it before hand it wouldn't allow the moisture to penetrate as deeply thats all. Made sense in my mind and I wanted the nitrogen to pressure test system. I did replace the schrader valves. Believe they are high flow standard valve core tool didn't fit I used needle nose pliers.

I am a junkie also and have been looking for a used recovery machine for a while but might end up going your way instead of a dedicated machine shops use. The guy in the video said to remove the line and plug it right away to keep the system pressurized so air can't get in. It makes sense but just not sure how possible that is. I would think that as soon as you lost pressure it allowed the air to start going into the system and replacing the nitrogen? I get the vacuum ***** it in at a much faster rate but would think after a few minutes after loosing pressure your system had air in the whole thing, but I'm not a scientist or whatever would know exactly how that works. Also don't know if vacuuming the air in would create more moisture or not, and then if pulling a vacuum on the system after the repair would get rid of all the moisture or not.

I'm with you on the nitrogen to purge and test before filling. Guess my question is about how bad sucking air in when opening the system under vacuum is vs opening it after purging with nitrogen? And then if that matters or will affect the vacuuming to get rid of moisture before charging? Just for my own knowledge. Your theory makes sense but I'm curious about how much it would make a difference. Ya those schrader valves are bigger and use a different size tool.