Purpose
This guide explains how to identify whether the Main Controller PCB (Printed Circuit Board) installed in an LATL outdoor unit contains the old or new control software.
Correct identification ensures the correct board and firmware version are used for servicing, replacement, or diagnostics.
1. Affected Models
Applicable to LATL series outdoor units, such as:
AOTG30LATL, AOTG36LATL, AOTG45LATL, AOTG54LATL, and related capacities.
2. PCB Identification Overview
Each Main PCB has a unique EZ number label and software version marking that indicates whether it contains the old or new firmware.
Identification can be performed visually from the PCB label or by verifying the serial marking.
3. Identification Methods
(A) By EZ Number
Locate the EZ Number printed on the white product label fixed to the Main PCB.
| PCB Version | EZ Number (Example) | Description |
|---|---|---|
| Old Software | EZ-343953 | Earlier control logic version |
| New Software | EZ-354482 | Updated firmware with revised sequence control and improved error detection |
⚠ Note: The EZ number may vary slightly by production batch, but the first five digits will match the examples above.
(B) By PCB Marking (Label and Revision Code)
Each PCB also displays a label code printed on the board itself, typically near the IC or EEPROM area.
| PCB Type | Board Code | Firmware Marking |
|---|---|---|
| Old Type | K10BS-110HUE-C1 | “IC300_A12” |
| New Type | K10BS-110HUE-C1 | “IC300_A15” |
The “A12” version corresponds to older firmware (before reliability updates).
The “A15” version includes control refinements for stability and compatibility with newer LATL configurations.
4. Software Compatibility
When replacing an old-type PCB, do not interchange with the new version unless the full software and EEPROM data are updated simultaneously.
Ensure the ROM Writer procedure (refer to relevant technical bulletin) is completed if updating from old to new firmware.
5. Label Example (from attached document)
Example label found on the new PCB:
This identifies the board as new version with software revision A15.
6. Summary
Identify the Main PCB using the EZ number and firmware marking.
EZ-343953 → Old version
EZ-354482 → New version
New PCBs (A15) feature enhanced control logic and improved reliability.
Always match firmware version when replacing boards to prevent communication or startup errors.