8-zone CPU module
Part number: C225
Description
The C225 is the main processing unit for iZone climate control systems. It handles zone control logic, communicates with AC unit interface modules (C325#), wall controllers, wireless sensors, and the Smart Hub. Supports up to 8 zones natively, expandable to 14 with a CEXT zone extender.
Installation guide
🧭ONLINE GUIDEC225 Installation Wizard→▶VIDEOGeneral installation walkthroughVIDEO→📐WIRING DIAGRAMC225 wiring diagramWIRING→
Step-by-step installation notes
- Mount C225 in the roof space or AC cabinet within cable reach of the AC unit
- Clip the C325# AC interface module onto the C225
- Connect the CT24ACE transformer to an earthed AU GPO — never wire to the AC unit supply
- Wire zone damper motors to zone ports starting at Zone 1 consecutively
- Connect the CDTS in-duct sensor to the CDTS port if using temperature sensors
- Run 2-core shielded cable from the AC unit serial terminal to the C225 terminal
- Power on and complete commissioning via the wall controller Setup menu
Specifications
| Entry | Description |
|---|---|
| Model number | C225 |
| Power supply | 24VAC 50Hz via CT24ACE |
| Casing material | Fire retardant ABS plastic |
| Operating temperature | Up to 65°C |
| Communications | Wired CAN Bus · Wireless 433MHz (iZone proprietary) |
| Number of zones | 0 to 8 (RJ11 or RJ12) — expandable to 14 with CEXT |
| Dimensions | H: 32mm (124mm with antenna) · W: 121mm · L: 117mm |
| Weight | 200 g |
Connectors & ports
| RJ45 iZone Net ports (×3) | Connect touch screens or CNEMK |
| Zone damper ports (RJ12/RJ11) | Zones 1–8, wire consecutively from Zone 1 |
| CT24ACE JST connector | 24VAC power input |
| C325# / CEXT port | AC unit interface or zone extender |
| CDTS port | In-duct supply air temperature sensor |
| RF antenna | 433MHz wireless sensors (CRFS#) and Smart Hub (COCBH) |
| Pair button | Pair wireless sensors and Smart Hubs |
| AC unit terminal | Spring-loaded 2-core shielded cable terminal |
Included in
C546K
Nova CAT kit
C545K
Nova DC kit
C536K
Nova Mini CAT kit
C535K
Nova Mini DC kit
C430+K
Nexus+ kit
C420K
Nano kit
C405K
Naked 8-zone kit
Related parts
CEXT
Zone extender
CT24ACE
24VAC transformer
CDTS
In-duct sensor
COCBH
Smart Hub
CNEMK
Network extension kit
CSL
Screen Link Module
Documents
Troubleshoot guide
Read more
Zones are not opening or responding
One or more zones are not responding when you try to open or close them. The zone port itself may be faulty.
Steps to resolve:
- Disconnect the zone motor from the problem port and plug it into a different unused port on the CPU
- In the iZone app, go to Setup → Configure AC → Options → Skip Zone Port (password:
wamfud) and skip the faulty port - Verify the transformer is powered and outputting ~24VAC
- Check wiring polarity and that all connectors are fully seated
Note: On Daikin systems, it can take up to two minutes for dampers to open after a command is sent.
Wall controller or screen is not powering on
The screen fails to power on, goes black, or shows no signs of life.
Possible causes:
- Faulty or damaged cable between CPU and wall controller
- Faulty C225 CPU
Steps to resolve:
- Move the screen's cable to a different iZone Net port on the C225 CPU
- If the issue persists, replace the cable between the CPU and wall controller
- If still unresolved, contact your installer — the C225 CPU may need to be replaced
No 24VAC supply — system not operating
The system has no power or zones are unresponsive across the board.
Check the following:
- Verify the transformer is plugged into an earthed GPO and the GPO is switched on
- Confirm output voltage from the transformer is ~24VAC
- Ensure the transformer is not wired directly to the AC unit's power supply — this is not supported
- Check wiring polarity and that all connectors are fully seated
Firmware history
Read more
3.77January 2026
- Added TCL ducted AC integration (IRD-211)
- Fixed Brivis reset command and quick on/off issue (IRD-854)
- Added AC On with Zone feature
- Added support for Nova controllers with CAT5 connection
- Added zone grouping (Daikin only)
3.73September 2025
- Overheat protection (default off)
- Brivis Integration via C325BV module
- VRF Mitsubishi Electric support via CVRFH module
- Remote firmware upgrade capability (C225 and COCBH only)