Suddenly most of my actuators report comms faults

[MisterBoy]

I have a 12-zone system that has been running for about 3 years. Suddenly today, most of my zones are reporting comms faults - within a couple of hours of each other. No temperature is reported on the main controller but the HR92 units seem fine.

Is there a big system update being pushed out or something? Or could something have failed - what can I do to diagnose?

[Richard]

Do you have a CS92A or DTS92A? If so the batteries are flat in this device and need to be replaced urgently.