I just installed a new Mr. Cool system a few weeks ago. Works great, its quiet and works as expected.

I haven't finished the lineset covers since the routing is a bit wonky so I was able to see the liquid line shaking while I was outside with the dogs.

Anything to be worried about?

Edit: Link to the specific unit https://www.homedepot.com/p/MRCOOL-Advantage-3rd-Gen-18-000-BTU-1-5-Ton-Ductless-Mini-Split-Air-Conditioner-and-Heat-Pump-230V-60Hz-A-18-HP-230B/308810697

Video https://youtu.be/1pYjNYvFjo8

  • Please edit your post wth a link to your Mr. Cool system. As it is now, it's unclear what you are asking. Aug 3, 2019 at 20:40
  • how are the dogs related to your question?
    – jsotola
    Aug 3, 2019 at 23:43
  • If you had a short video of the movement that might be helpful. As I said in my answer some movement is normal and I believe your line set is flex line not soft copper so there may be more movement on your line set depending on how you secured the lines or excess of close to the outside unit.
    – Ed Beal
    Aug 10, 2019 at 16:14

1 Answer 1


I just had a training class that mentioned these units a few weeks back (even offered a bounty to get more views). The system comes fully charged you just assemble it and connect the lines. All hvac systems vibrate and this is normal. I hope you reviewed the instructions and the feed back to seal the threads on the line set. I use nylog (nylog blue for the last few years). Movement is somewhat normal especially with the 25’ line set so having the thread sealant is a good idea and will reduce the number 1 cause of failures low refrigerant (this was what the instructor told us). Yes some vibration is normal the pad you mount the unit helps dampen this, so I would not worry two much about that.

With dogs (I love dogs and have them) make sure they do not pee on the outside unit. Dog pee is very corrosive and will wipe out the outside coil much faster, I have seen this several times on systems where dog pee ate the fins and eventually caused holes in the tubes. But as far as some vibrations of the pipes this is normal.

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