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  • July 28, 2024 at 1:51 pm #1484
    theachub_m40wgrTheAChub
    Keymaster

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      Hi
      I have an issue with a Mitsubishi city multi system not providing much heat.

      system is circa 2001 – but still in reasonable condition. Outdoor is a PURY P250 YMF with 9 ducted PDYF P20 indoor units. I suspected it may have been short of gas – but recovered and gas charge – is as per commissioning sheet.

      Hot gas seems to reaching the BC box(49c) – but air off temp at indoors is only around 22c

      I got the following data from sw1

      Comp freq 82
      Discharge 20 bar
      Suction 3 bar
      BC box P1 47 P3 39
      TH11 10.3
      TH12 1.7
      TH13 99?
      TH14 99?
      TH15 0
      TH16 12.8
      LEV 3 440

      INDOOR LEV’S – ALL AT 2000

      Any ideas?

      July 28, 2024 at 1:51 pm #1485
      KingACKingAC
      Participant

        What are your actual suction and discharge pressures? Do they correspond to what the system thinks the pressure transducers are reading?

        July 28, 2024 at 1:52 pm #1486
        theachub_m40wgrTheAChub
        Keymaster

          Premium

          Yes – gauges read the same as sw1 readings

          July 28, 2024 at 1:52 pm #1487
          KingACKingAC
          Participant

            Is it 407c? What discharge temp are you getting? Is compressor at full speed for above readings?

            July 28, 2024 at 1:53 pm #1488
            theachub_m40wgrTheAChub
            Keymaster

              Premium

              Yes it’s a 407c unit. I spent a bit of time looking at it today.one thing I found – was that th1 thermistor{ compressor discharge) was reading 123c even with the unit off, I changed the sensor but it made no difference, still showed 123c when running, when-pipe temp was only 76c.

              Would this be enough, to stop the compressor ramping up to full load ? Im presuming it must be an issue with the main board causing the sensor reading error.

              I have a board off a PUHY YMF C, it looks the same, but was going to check to see if it’s compatible with a PURY unit, as a replacement board is £350 .

              July 28, 2024 at 1:53 pm #1489
              KingACKingAC
              Participant

                Yes, i think this will prevent full load on compressor, big weird that just this thermistor is not reading right, worth checking board though.

                July 28, 2024 at 1:53 pm #1490
                KingACKingAC
                Participant

                  If this is a PURY-P250 YMF-C unit than the discharge temp. probe is TH11 and not TH1.

                  July 28, 2024 at 1:54 pm #1491
                  theachub_m40wgrTheAChub
                  Keymaster

                    Premium

                    Hi, thanks for your reply.

                    yes its a PURY – P250 YMFC CIRCA 2001

                    I was just going by the handbook I have image 2 pury ymf c .jpg sw1 .jpg

                    My manual doesn’t list any SW1 switch settings for a th 11 – do you have them

                    thanks

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