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We illustrate how to recover refrigerant from a system with a working compressor. The system in this video is being decommissioned, so it is acceptable to recover refrigerant while a unit is running if it will no longer be in operation after the recovery.
We use the Fieldpiece MR-45 digital recovery machine instead of a manifold to recover the refrigerant (you can find that machine at
It is a good idea to recover for a bit before turning the recovery machine on. On the machine, you will see the input and tank pressures start to equalize. Some units, like the Fieldpiece MR45, can be throttled. When the machine starts, the tank pressure will rise a bit and pull the refrigerant in relatively quickly.
Remember to weigh the charge in the tank every time you recover. Keeping the tank on a scale can also let you see the slowdowns in recovery. However, even if you don’t use a scale, you can still tell when your recovery is almost finished; the inlet pressure will drop heavily when the refrigerant has been almost completely recovered.
Even though the unit is running, the best practices remain the same: use large hoses and core removal tools for fast evacuations. However, another best practice is to place something on the condenser unit, such as a toolbox, to raise the head pressure during recovery and increase the pressure differential that allows the refrigerant to flow out. As an optional practice, you can take a pinch-off tool and crank down on the liquid line to raise the head pressure even more.
This procedure will be crucial as we decommission more R-410A units. You will notice an uptick in R-410A systems being decommissioned as R-22 slowly disappears.
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I'm just gon na shoot this quick video on recovering gas out of a unit. That's going to be decommissioned. That has a running compressor, so i've got this unit set to run, got my core remover tools and hoses on there, because i like to recover fast. But that's kind of optional right already got this purged out to the cylinder.

When you have a working unit and you're decommissioning it you don't care about it anymore. You can use the compressor. That's already running. You can see i'm pushing gas through here now.

As you see your pressure in your tank and your input start to equalize, if you have a recovery machine that can be throttled. Actually i had that backwards with the pressure i wouldn't have been moving much gas, but we got that nice sub cool liquid pushed into the machine through the input. This is our 22 to the output on the tank side. As you can hear, it's not having a hard time with it the recovery machine.

What you want to do at first, though, is you want to let a decent amount of gas just flow through before you start up your recovery machine that way, you're not killing your compressor. Now i also have my case on top of the unit raising head pressure that helps, you know, create a pressure differential to get gas out. In this case, we block the condenser a little bit if it's convenient and optional, but not necessary step two is you can take a pinch off tool and crank it down on the liquid line, i'm only pulling through the high side right now very important. I do not have the low side open to my machine, so i could crank this down on there but looks like our head pressure, this unit's at like 100 right now, anyway, the left is our inlet pressure of our recovery machine.

The right is the tank. So that's head pressure right now, of course, with this compressor running too so now we can go ahead and shut it down. I have my suction open now too, so you can see how little gas was in that unit. How fast that all came out now.

I didn't weigh it in this case. You should always weigh it. You know not the greatest example, but especially on 410a. This will really help and as we get further along we're going to be decommissioning 410a more and more and there's going to be less and less r22 units.

So this will keep your tank pressure much lower, especially with 410a. Thanks for watching our video, if you enjoyed it and got something out of it, if you wouldn't mind hitting the thumbs up button to like the video subscribe to the channel and click, the notifications bell to be notified when new videos come out, hvac school is far More than a youtube channel, you can find out more by going to, which is our website and hub for all of our content, including tech tips, videos, podcasts and so much more. You can also subscribe to the podcast on any podcast app of your choosing. You can also join our facebook group if you want to weigh in on the conversation yourself thanks again for watching you.


8 thoughts on “Recovering refrigerant w/ a working compressor”
  1. Avataaar/Circle Created with python_avatars Robert Cherry says:

    I usually use the compressor to move most of the refrigerant straight in a recovery cylinder.Than the final 10 percent is removed in vapor form with the recovery machine,Faster this way,and less work of removing the liquid refrigerant,for the recovery machine.

  2. Avataaar/Circle Created with python_avatars Mark Atwood says:

    Does it make any difference flipping the recovery tank? I've heard it recovers faster if you flip the tank and use the vapor port as it creates less resistance for the refrigerant entering the tank.

  3. Avataaar/Circle Created with python_avatars Nor-Cal Refrigeration & H.V.A.C says:

    The MR. 4555555555

  4. Avataaar/Circle Created with python_avatars john mavok says:

    The amount of time of setup would be more than just hooking up the recovery machine and cooling the tank down with water. Are you in Orleans ?

  5. Avataaar/Circle Created with python_avatars The Long Road Home says:

    I just run the indoor fan and use a cool collect in a bucket of water🤙🏼 i'll try this method but I don't think it'll be any quicker lol..

  6. Avataaar/Circle Created with python_avatars Eassyheat/ Cooling says:


  7. Avataaar/Circle Created with python_avatars Raul Pimentel says:

    What ever you do don’t buy your equipment from the pawnshops?

  8. Avataaar/Circle Created with python_avatars Silky_ says:

    Question. In some cases the condenser is inoperable, would it still be best to pull only from the liquid side?

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