Air Conditioner - Compressor Issue

LHoborg on 20/04/2022 - 12:30
Last edited 22/04/2022 - 19:55 by 1 other user

This is a long shot, but thought I'd post here anyway.

About seven months ago, I got a Mitsubishi split system, model number: ME PEA/PUZRP170 (pulled from the invoice), air con installed. It cools and heats a 4BR 2Bath 2living room home that has a fair amount of north/east sun exposure.

When I run it on heat/cool, it emits this high pitched noise (on fan only, it's virtually silent). The high pitched noise is worse in the morning and improves throughout the day. This is a short recording of the noise after it ran for about 30minutes (at 8am). It was recorded in the room next to the compressor, which has a brick veneer wall in between (it's even louder outside). (You'll hear one of my kids briefly in the 4s clip - please ignore)

The installer come over as part of a warranty investigation and they believe that's just how the unit is… But I'd like other opinions, especially given the cost of the unit/install.

Any ideas/suggestions are very welcome.

EDIT: Thanks all. I've convinced the installer to send a tech over on Friday morning (when it's cold) so they can hear it. Will provide an update on the outcome.

EDIT #2: they pushed it back to Tuesday. But I did call the electrician they used as a subby, who is quite sure it's a PCB issue Will update again Tuesday

Electrical & Electronics Air Conditioner Mitsubishi

Comments

  • MS Paint on 20/04/2022 - 12:32
    +2

    Compressor bearing noise?

    • Hoborg on 20/04/2022 - 12:33

      I know very little about it… is there any other way I can confirm?
      (Perhaps just getting a second air-con maintenance guy out is the best solution)

      • MS Paint on 20/04/2022 - 12:37
        +1

        Has it made that sound since day 1 of installation or progressively got louder over the last 7 months?

        • Hoborg on 20/04/2022 - 12:39

          The sound has been there since I first started using it (October/November) but feels like it's worse on heat than on cool.

          I can't say I've noticed it get progressively louder.

  • Master Bates on 20/04/2022 - 14:22
    +1

    That is not normal. We have an ancient ME split system and it doesn’t make that noise.

    • Hoborg on 20/04/2022 - 14:38

      Thank you - appreciate the comparison.

      For what it's worth, I convinced the installer to inspect it early on Friday morning.

      Will see what he says.

  • flagger on 20/04/2022 - 16:24
    +2

    Not normal. If that's what your hearing inside with a wall in between, I would have been claiming warranty on day 1. Sounds like your installer doesn't want to fix the system. You may have to contact Mitsubishi if you get no love from the installer.

  • brad1-8tsi on 20/04/2022 - 17:01
    +2

    Not normal.

    At me old employer we had hundreds of Daikin and Mitsubishi Heavy Industries (better than Mitsubishi) ACs and none were ever like that.

    Whenever a tech says "that's normal" and you think it isn't ask them for examples of the same "normal" in other installations. Video or a visit to a showroom or another installation.

    • Hoborg on 20/04/2022 - 20:57

      Thanks - that's a great idea. Will do this if they come back with 'that's normal' again.

  • CheapukeeSkate on 20/04/2022 - 18:41
    +3

    Sorry to disagree with everyone, but my in my opinion this is normal for some brands of inverter air conditioners.

    I believe we are hearing the switching frequency of the PWM of the unit. It will change in pitch depending on the load on the airconditioner, hence why it sounds different in the morning (louder on heat as it is cooler), or during heat vs cool mode as the compressor requires more torque.

    Similar comparison to the cheap Pioneer units that are all over the internet: https://youtu.be/43XKfuptnik?t=2293

    Is Mitsubishi Heavy actually better than Mitsubishi Electric? This would suggest they are from a noise point of view as the PWM frequency seems to be further out of the audible range. Hitachi drives are very noisy but generally of high quality (Heard them called "Hiscratchy").

    • Hoborg on 20/04/2022 - 21:00

      FWIW - it's a 16kw system, running on low fan, heating the house from 18 to 21 degrees (Outside was 12 degrees at the time)
      I shouldn't be pushing the unit very hard at all.

      Also, I would assume this is at least a mid-range unit. It should perform better than the cheaper ones…

      But I'm no expert and will definitely take your response on board - thanks.

    • brad1-8tsi on 22/04/2022 - 07:30

      MHI are better than Mitsubishi and they are separate companies with different owners.

      Daikin and MHI are on par with each other in terms of quality but I prefer Daikin as (last time I was buying ACs) they use their own employess for warrantee whereas MHI sub-contract warrantee.

  • Stewardo on 20/04/2022 - 19:51
    +1

    Warranty claim for sure.
    Maybe call a different Mitsubishi warranty repairer than the one that installed it.

  • flagger on 27/04/2022 - 12:44

    Did you manage to get someone to look at it?

    • Hoborg on 27/04/2022 - 18:29

      They pushed me to today, then no show…
      Trying again

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