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AC Unit Interface Module Troubleshooting

Applies to: C325# (AC Unit Interface) · CUCMK (Universal Control Module)

AC unit not responding to iZone commands​

The AC unit does not turn on, off, or change settings when commanded via iZone.

Steps to resolve:

  1. Confirm the C325# module is firmly clipped onto the C225 CPU
  2. Check the 2-core shielded cable from the C325# terminal to the AC unit's serial input terminal — re-seat both ends
  3. Verify the AC unit make/model matches the C325# variant installed (e.g. C325DAI for Daikin, C325MHI for Mitsubishi Heavy)
  4. In the iZone app, go to Setup → Configure AC and confirm the correct AC brand is selected
  5. Check the AC unit is powered and its own control board is functioning (test with the AC unit's own remote)

CUCMK not controlling the AC unit​

The Universal Control Module is not sending commands to the AC unit.

Steps to resolve:

  1. Confirm the correct AC brand profile is programmed into the CUCMK via the iZone commissioning process
  2. Check the IR blaster is positioned with a clear line of sight to the AC unit's IR receiver
  3. Ensure the shielded cable from the CUCMK to the C225 is correctly wired
  4. Test by using the CUCMK's manual test button (if available) to send a test IR command
  5. If the AC unit has a wired receiver option, use that instead of IR for more reliable communication

iZone shows incorrect AC unit state​

The iZone app or wall controller shows the AC as off when it is on, or shows wrong temperature/mode.

Steps to resolve:

  1. This can occur if the AC unit was operated with its own remote — iZone loses sync
  2. Turn the AC unit off completely from iZone, wait 10 seconds, then turn it back on from iZone
  3. For systems using the CUCMK (IR control), always control the AC unit exclusively through iZone to maintain sync