The triple evacuation of the air conditioner

[@TandNServices]

I was taught to use refrigerant to break the vacuum. I also just open the liquid side on the initial vacuum. The reason I do it like that is because a long time ago I was doing start ups on apartments I kept having restrictions when I started up the systems, I found out if I just opened the liquid side for a little bit I would find the restriction before I opened the valves.

[@jimrodriguez4368]

So what were the final micron readings? Did the 850 go lower?

[@grayfurnaceman]

Jim Rodriguez In this case it did not. Units that have been open will usually drop with each vacuum. GFM

[@neitzsche5150]

GFC, your method makes a lot of sense. Most of us were taught to break a vacuum with dry nitrogen, which, as you stated, is, in fact, a non-condensable. This may be due to the confusion over the vague and nebulous definition of "deminimus discharge". Thanks for sharing.

[@grayfurnaceman]

When I work on systems, the best work I can do is what I will do. Breaking with nitrogen is not the best work. The small release of refrigerant is, to my mind, deminimus. GFM

[@RobHVAC]

Nice video Grey.

[@Fireship1]

Good procedure. Thanks for sharing - Jack

[@dcrickerson9775]

It makes sense to me. Thanks for sharing.

[@Newpark7]

All makes sense to me. I like it.

[@carlosportillo8863]

Thanks Did you have to recover vapor refrigerant that was used to break vacuum?

[@grayfurnaceman]

No, I consider it a deminimus release. GFM

[@mark.r8900]

Hi, after replacing a suction line and liquid line service valve do you perform the vacuum with both valves open? If so, wouldn't the vacuum pump pull compressor oil out of the system? Thanks

[@grayfurnaceman]

I follow what I said in the video. Why would you think it would remove oil? GFM

[@mark.r8900]

I've always performed vacuum from closed service valves through line sets and indoor evaporator. So I wasn't sure if I had to vacuum an empty system the strength of the vacuum pump might suck some compressor oil out. Will the vacuuming suction strong enough to do this? Thank you.

[@mark.r8900]

Also a complete vacuum would include evaporator, line sets, compressor and condenser coil. Is this correct? Thanks

[@grayfurnaceman]

@@mark.r8900 A very deep vacuum will start some boiling of the oil, but you would have to leave the vacuum on for several weeks to have an effect. Yes, a complete vacuum includes all parts of the system. GFM

[@mark.r8900]

You're by far the best instructor I've ever seen. Thank you.

[@jarrodabel4529]

How many ounces of 22 did it take to bring it back to 0 psi? 5 or so?

[@mikewells9896]

Great video...

[@grayfurnaceman]

Mike Wells Thanks for the support. GFM

[@cmalinoski]

Gfm I got a question ? What if you weren't using R-22 ? Say you were using MO-99 or R-410a / A blend... On your 2cd Evac step,you introduced (Vapor) to the Vapor side. Obviously with a blend you always intro Liquid... Could you introduce the Liquid to the Vapor side as you did. To push the contaminants thru the evaporator thru the expansion device also out thru the Liquid port,and thru the compressor & condenser ??

[@grayfurnaceman]

cmalinoski It will work just the same. You just have to be careful about the amount as the liquid puts more in faster. GFM

[@cmalinoski]

Thank You Sir. For your response. Keep them video's coming. Always a go to for me. Really liked your video on the capacitor calculation thing. I too have noticed doing it that way.seems to always show Caps reading low.While under load. Even new Caps.Huh ??

[@grayfurnaceman]

cmalinoski I did not show the other motors I tested. Some read more, some read less. GFM

[@haroldabbot7763]

should the micron reading come down each time you evacuate? steve australia

[@grayfurnaceman]

It should if the system is clean with no leaks. GFM

[@melllvar4262]

You are a Rebel GFM 😊

[@Lestat103]

I'm about to do a tripe evac on a compressor air dryer, and will be following your method. I see you haven't removed the valve cores. Is that an optional step, can you connect your hoses directly to the service ports without compromising the job? I don't care about faster evacuation, but I only want to do this job once.

[@grayfurnaceman]

Actually, the cores are removed. GFM

[@blissJesus1]

I have a job tomorrow that may require this type of vacuum. My hope is the non condensibles are not the dessicants from the filter dryer. Slight pressure fluctuations within semi-normal operating pressures, but the line freezes. I never saw ice in nearly 2 hours of run time. I have clean indoor coil and filter. I have clean outdoor unit with normal superheat, and subcool is at the upper range of 20. I suspect a restriction in this system

[@grayfurnaceman]

blissJesus1 If you suspect moisture in the drier, I would replace it. Most any time you open a system, the drier should be replaced. If it has a fixed orifice, it should be removed and checked. If it is moisture, it will usually operate normally for a few minutes, then block. Warming the expansion device will melt the moisture. Hope this helps. GFM

[@dpeagles]

I have seen debris flow into the piston and cause problems. Then when the unit shuts off the debris would flow back into the line. So it may take hours for it to show back up at the piston. Finally just installed the filter/drier right at the piston. Never had another problem.

[@blissJesus1]

thank you for your time; I started looking into airflow on the system, and learned the customer had switched two runs, I did not think it would makea big difference but they were not freezing before they did this. I only had 850 cfm at the return, on a 3 on system, and it is all flex, that has many twists and turns, and sags. After I correct the duct, i will check pressures again. If the situation persists, I will go into the piping.

[@rabaimokrani2745]

Why not use thicker hoses. It gives a better vacuum?

[@grayfurnaceman]

The depth of the vacuum will not increase appreciably with thicker hoses. The reason for the triple vac is 3 evals to 1500 microns is better than one to 500. By breaking the evacuation with refrigerant or nitrogen, you are sweeping out contaminants more effectively than one evacuation could do. GFM

[@carlosportillo8863]

Thanks great video. Did you have to recover the vapor refrigerant on the second evacuation?

[@Jimddddd1981]

If you where evacuating a 410 system the process would be the same except you would break the vac with liquid. Correct?

[@grayfurnaceman]

Jim D You got it. When putting in liquid, a little means a lot. GFM

[@juanmaldonadojr.8947]

That was my question lol!

[@cliffmeima2015]

I like it.

[@johnfrancis4748]

SMH you need to go back to school

[@awesomeaustin2348]

This is so wrong, you should take this vid down !!

[@grayfurnaceman]

What is your problem with the video? GFM

[@awesomeaustin2348]

@@grayfurnaceman Assuming this unit doesn't have any leaks, and the heat pump and indoor coil are close together for instruction purposes or 60ft away it doesn't matter, it took 22 mins to pull down system to 833 microns, it should have taken less than 5 mins to pull down to 250 or less. Your rigging is all wrong, pulling a vac through a set of gauges (1st restriction) and then through a 1/4 hose (2nd restriction) into the 1/4 port on the vacuum (3rd restriction) is not the best practice of pulling a vac. Also on a triple vac you should always break your vacuum with dry nitrogen, not refrigerant because technically and lawfully you now have to recover that refrigerant and start over. I thought I herd you say you did pull out the schrader valves which is good because that would have been 2 more restrictions. Now I'll admit I'm a commercial/industrial guy, mostly industrial but I do work on some split units in some offices from time to time but I pull my vacuums with the same rigging, 2 ton heat pump or a 500 ton chiller.

[@grayfurnaceman]

@@awesomeaustin2348 Good answer. I usually don't get that. I do however have some issues and explanations. I have never, ever, had any unit evacuate to 250 microns in 5 minutes. Not a new one, old one, small or large. With or without gauge set, large or small hoses, new hose, large vac pump, new vac pump, old vac pump, anything. In fact, I have never had a unit pull to 250 microns at all in 35 years of service. I test my vac pumps periodically, and they are capable of 60 to 80 microns. The fact is, when pulling a vacuum, you will use a gauge set, as most smaller units do not have any way to isolate. I will say that a 3/8" hose is sometimes useful, although its value is somewhat overrated. As for breaking the vacuum with refrigerant, the use of nitrogen is simply adding in a non condensible into your system. I would want refrigerant and only refrigerant in my systems. Remember, evacuation only removes a percentage of what is in the system, not all of it. The refrigerant released is deminimus as it is about 1% of the charge. The bleeding of the hoses filled with liquid can easily exceed this amount. GFM

[@awesomeaustin2348]

@@grayfurnaceman Your vac pump is a 5 to 7 cfm , your rigging has reduced your volume down to a approx. 0.5 cfm at best, if your lucky.. I pulled down a 40 ton McQuay unit I replaced 2- 20 ton compressors, 2- core driers, repaired 2 leaks, 1 in the discharge line and 1 in the hot gas bypass line, pulled it down to 246. 2005-R22 bomb. It gets done daily my friend . Your vac pump is rated to pull down to 50 microns, close it up and only put your micron gauge on it, You'll see.

[@awesomeaustin2348]

@@grayfurnaceman Sorry, I can't break my vacuum with refrigerant, I'd lose 15 lbs or more .