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Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: UGLYTRUK ()
Date: August 05, 2018 07:26PM

I attended the AC tech session, and one of the attendees mentioned test charging my newly installed system with nitrogen. Its a stock style 1966 version condenser. Before I try fill it with R12, how does one use a micron gauge to check for leaks? I've used the hang style gauges a few times, but I'm far from a pro! I will be ordering a new reciever dryer from Rock Auto. They sell two GM styles, neither of which is "listed" for the Corvair, but they sure look very close!

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: MattNall ()
Date: August 05, 2018 08:13PM

No idea!! I just checked the Web... Gauge! over time...


Spray bottle with soapy water will show and leak as bubbles.





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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: Frank DuVal ()
Date: August 05, 2018 08:55PM

Use micron gauge to see what the vacuum is in the system while using the vacuum pump. 500 microns is real dry system. 1000 microns is good. When the system is pulled to 1000 microns, leave it under vacuum, with pump valved off. The first rise in microns will be water vapor gassing off. If you cannot achieve 1000 microns, there is a leak.

Then you break the vacuum by connecting the nitrogen bottle to the system and flood the system with nitrogen.

You can then pull another deep vacuum, if there was sill some water vapor is the system as shown by rising micron gauge.

Here is a graph of microns vs time

[www.refrigeration-engineer.com]

Frank DuVal

Fredericksburg, VA

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: UGLYTRUK ()
Date: August 05, 2018 09:08PM

It seems a micron
gauge is $150ish, and I was hoping to see a ytube vid of exactly what to buy and how to use it and the technique for filling with nitrogen

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: MattNall ()
Date: August 05, 2018 09:20PM

Non liquid Nitrogen comes in bottle like Oxygen

$150? you won't pay that for a Tire...why a useless gauge?





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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: ChillerPhil ()
Date: August 05, 2018 10:10PM

The initial leak check should be at a positive pressure consisting of a Refrigerant "Trace Gas" and Nitrogen. Then an Electronic Leak Detector, Gas Sampling, is utilized for leak detection. If no leak indications are found, then you should evacuate. A "Soap Bubble Solution" will reveal significant leaks. An Electronic Leak Detector is required for minute leaks, ones easily missed with "SBS". In evacuation, utilize new oil in the vacuum pump, as fouled oil will diminish its ultimate pressure. Also,prove your vacuum pump performance with a Micron Gage prior to evacuating the system. As to pressure increases while performing a "Standing Vacuum" test, leakage will increase continually while water will increase to its vapor pressure relative to the ambient.



Edited 1 time(s). Last edit at 08/05/2018 10:13PM by ChillerPhil.

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: MattNall ()
Date: August 05, 2018 10:33PM

Now that's great info! Welcome to the CCF!





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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: moomba32 ()
Date: August 06, 2018 01:54AM

I enjoy reading info when the writer actually knows what's he's writing about, well done Phil and Frank.

Don Marlowe
66 Monza 2Dr 140/pg
64 Spyder convertible now, 110/pg
Eutawville SC

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: Phil Dally ()
Date: August 06, 2018 03:52AM

Another smart guy named Phil...who knew!!! smiling bouncing smileysmiling bouncing smileysmiling bouncing smiley

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: UGLYTRUK ()
Date: August 06, 2018 04:27AM

Great info Phil, I'm feeling chilly already! eye popping smiley

But I'd really need a parts list, and a how to ytube video, bcause if a pix worth 1000 words, then a video is worth 10,000???

As far as tires goes MATT my 215 60R14's measure 24" inflated. A 185 80R13 measures 25", so I priced a 225 60R14, the same size as equipped on my 8 lugged equipped '65 Grand Prix. For whatever reason, they're $10 cheaper!. So I'll be ordering 2 this AM, possibly even using my discount tire direct CC which offers 6 months zero interest if paid monthly (min charge) and in full within 6 months, but the cheaper eBay price, $112 delivrd may not allow the CC offer I've used for other tires, and discount tire is always the least expensive option, always free sh, and I have my own vintage Coats 2020 tire machine and $80 harbor freight balance.



Edited 1 time(s). Last edit at 08/06/2018 04:31AM by UGLYTRUK.

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: junkman ()
Date: August 06, 2018 05:17AM

A micron gauge is a helpful tool, because the higher the numbers go on the gauge, the deeper your vacuum is. My vacuum pump will pull the system down to 30 inches of mercury, and when I leave the pump going for a few hours, it will bring the micron gauge to 10,000 (SUPCO VG64 Digital Vacuum Gauge). The highest number that I have ever experienced is 14,000. Just because your system holds a vacuum, it doesn't prove that it will hold pressure. This is where a nitrogen bottle comes into play. You pressurize the system with nitrogen to 200 / 250 PSI, and shut off the flow to the system. Wait a few minutes, and the system should balance on both the high and low sides. After a half hour / hour, check your pressures. Depending on how much it has dropped, will tell you how big of a leak you have. If it doesn't drop, you are good to letting the nitrogen out of the system, and to charge the system with your refrigerant of choice. I once had a system that had a slow leak, so I put a pound of refrigerant into it and I hunted for it with an electronic leak detector and could never find it. I had to resort to putting dye into the system, only to find that a hose had become porous.
I remember in the "old" days, if a car lost a 12 ounce can of refrigerant a year it was considered acceptable. Today, any loss of refrigerant is not to be tolerated.

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: UGLYTRUK ()
Date: August 06, 2018 06:23AM

Informative junkman

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: Frank DuVal ()
Date: August 06, 2018 01:16PM

Just looked up the VG54 and it is a typical great micron gauge, so the readings are lower numbers for better vacuum. 500 microns is the goal for a dry system.

10,000 microns is 29.53" Hg, 98.7% of pure vacuum, 10 Torr, 10 mm Hg.

750 microns is 29.89" Hg, 99.9% of pure vacuum, .75 Torr, .75 mm Hg.

As you can see, lower numbers better. Now, I have never attached a micron gauge to an automotive system. I do use one on our chillers at work, and regularly get them down to 500 microns with an electronic gauge, waiting for the water vapor to boil off.

For most car work, since I am not in a hurry, I just let the vacuum pump run for hours, shut the valves, wait overnight and see if the vacuum diminishes. Also putting heat on the receiver dryer helps boil out trapped moisture. Heat lamp, NOT torch!eye popping smiley

Breaking the vacuum with nitrogen also helps remove moisture from the system.

I use an electronic sniffer to find leaks.

Frank DuVal

Fredericksburg, VA

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: jjohnsonjo ()
Date: August 06, 2018 02:27PM

Also putting heat on the receiver
> dryer helps boil out trapped moisture. Heat lamp,
> NOT torch!eye popping smiley
>
>

If I know there is a hot day coming, I park the car in the sun and turn the pump on in the morning. Its a lot faster at boiling off the moisture. Waiting for a cool day to do the job can mean more pump time.

J.O.

65 Corsa Turbo Vert
79 Honda XL 500S
69 Honda CL 160 D
2010 BMW F 650 GS
2003 Bounder 36D
2013 KIA Optima SX turbo-AKA ZIPPY (wife,s car)
69 Newport Holiday Sailboat
Baja 150 dune buggy cart
Coleman HS 500 UTV
2016 KIA Sorento SXL Turbo

Bethlehem,Pa

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: robert wilkinson ()
Date: August 06, 2018 03:40PM

Good information! I would only add that dry nitrogen serves not only to purge the system of some additional water, but it allows better leak testing (using a halogen leak detector) than is possible with pure refrigerant.

The reason is that you can use 200 PSI or so pressure (system not running of course). This is about the same as the high side sees when running, but you don't need it running. AND, its much higher than the low side ever sees, running or not. That's because the vapor pressure of the refrigerant will be 80 PSI or so, depending on ambient temperature. So leak testing is more sensitive.

You need to add refrigerant to the N2, which is legal as long as you add just a little. This refrigerant will be vented to the atmosphere, of course, but there is a provision by the EPA that allows it (the amount of added refrigerant is defined as "de minimus" so its up to your conscience--but a few oz suffices nicely).

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: ChillerPhil ()
Date: August 06, 2018 09:02PM

Additional "Best Practices";
Pressurize the system incrementally. For example pressurize to 50#'s and check. First by listening, if leakage is heard, feel for it with your hands. If you can not feel it, spray the SBS in the location and check visually. You may need an inspection mirror and a flashlight. Also, watch your gauge pressures for movement.
If it passes that pressure test then increase to 100#'s and then utilize the electronic leak detector.
Final test pressurize is below the Low Side Burst Pressure for the system.
Depressurize and begin the evacuation process.
A standing vacuum test is only a 14.7# test pressure on the system,i.e. our atmosphere pressurizing the exterior of a system at 500 micron vacuum internally.
It feels quite good to be able to contribute to this community, I appreciate the comments.
Frank, the chillers you mentioned, vapor compression or absorption cycle?
JO. , great practical information definitely applicable to proper refrigeration practices.
robert, you must work in HVAC/R.
Matt, I have been reading, offline primarily, for a few years. CCF is my favorite forum. Some day I will own a corvair, but learning in the mean time.



Edited 1 time(s). Last edit at 08/06/2018 09:03PM by ChillerPhil.

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: MattNall ()
Date: August 06, 2018 09:04PM

We appreciate your contribution! Let's us know when you are looking to buy!





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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: UGLYTRUK ()
Date: August 06, 2018 09:21PM

I bot this machine last year at a swap meet. I was promised it worked, the fellow even plugged it into his generator. I didn't pay much, maybe $50? Maybe less... Dunno... Anyways, a fellow who passes by regularly used to run a starter alternator shop locally, and he did AC recharging on cars, so I figured he'd help me figure the machine out...

I ordered 2 receiver dryers from RA, when they arrive I'll look for a Ytube video demonstrating the micron gauge and nitrogen charging technique. Images anyone?

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: Frank DuVal ()
Date: August 06, 2018 09:24PM

Phil, Vapor compression.

We did have an experimental PLMC (Pumped Liquid Multiphase Cooling) system, but it isn't a "chiller" as ambient is best you can do. It does move a lot of heat energy from a process to the outside air.

Frank DuVal

Fredericksburg, VA

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Re: Nitrogen:How To Test My AC System For Leaks? And Micron Guage-HELP! eye popping smiley
Posted by: ChillerPhil ()
Date: August 06, 2018 10:40PM

UglyTruk.
Start with yellowjacketuniversity.com. That is the first one that comes to mind. They have articles, videos, Q & A and you can even get a Degree in Cool.
Check appiontools.com in their videos section.
Check jbind.com in their FAQS section.
Frank, PLMC is not a refrigeration application that I am familiar with, but sounds interesting. What tonnage and is that a cascade system?
It is amazing at the many different ways that refrigeration is applied and that in vapor compression only.
ChillerPhil.

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