If there is any issue with the screen and you see it flickering and beeping, There could be a few reasons for that to happen.
In order to rectify the issue, you can check:
1️⃣ If there is any intercom or other device that is plugged into a 240Volts cable in the roof or cavity near Nexus or Nano Panel
2️⃣ Check if there is anything that is hard-wired and could create a magnetic field around the CAT 5 cable of Nexus or Nano control panel.
3️⃣ if the cable is a normal cat5 cable you can replace it with a shielded cat 5 cable.
If the issue persists, the Electrician needs to be called as they can check:
if the indoor unit and iZone CPU is sharing the power in the roof.
Some installers install the iZone CPU by hardwiring the transformer to the power source of the indoor unit of the Air conditioner. That also causes a screen to flicker