Mitsubishi City Multi VRF - LOUD noises (pls take a listen)

[kaon]

Hi all,
I have a few units of Mitsubishi VRF PUHY-P400YHA that are making these awful noises audible in the conditioned spaces.

Listen here: https://soundcloud.com/dt5433/mitsub...-multi-vrf-air

The system has had this problem from day 1, and it has been running for about 4 months now, the noise seems to happen more often during low load, and it will occur about once every 15 minutes. Mitsubishi techs have called it "balancing noise" and are unwilling / unable to solve it. They just changed some settings / firmware using their laptop to reduce it, but it seems to be about the same.

Any ideas and insight would be greatly appreciated, thank you!

[kaon]

It is a noise of SV1 solenoid valve. Discharge-suction bypass, capacity control during low load operation.
It is ON while the compressor is operating at the minimum frequency and when the low pressure (63LS) drops
below 0.23 MPa [33 psi]. It is OFF when low pressure (63LS) exceeds 0.38 MPa [55 psi].

Do you mean the bypass occurs because cooling load is too low?
Why not just stop the compressor?

If you have to run outdoor unit with low load you have nothing to do with that.

Sorry, I don't understand this. Can you rephrase or elaborate please?