| Feature | Color | Explanation |
| Boiler | Green | On: Boiler demand active Off: Boiler demand inactive |
| Pump | Green | On: pump demand active Off: pump demand inactive Flashing: Temperature limiter/dew point monitor active |
| Mains voltage | Green | On: Device in operation Off: Device out of service Flashing: Commissioning mode active |
| Fuse | Red | On: Fuse defective |
| Change over | Blue | On: Cooling mode active Off: Heating mode active |
| 8 room thermostats | Green | On: active thermostat signal, heating request Off: inactive thermostat signal, no heating request Flashing (long – short): active thermostat signal, heating request, room is not currently participating in load balancing Flashing (long – long): Display “Disable cooling” |
| Factory reset | Red | ower LED flashes red quickly for 5 sec, all other LEDs are off |
| FirstOpen Function | Green/Orange | Power LED flashes alternately green/orange + input LEDs are lighted during function; all other LEDs (pump, boiler, CO, etc.) as in normal mode |
| ManualOpen Function | Green/Orange | Power LED flashes alternately green/orange + CO LED flashes + all other LEDs (input LEDs pump, boiler, etc.) as in normal mode |