General Assist Technical Reference
Identifying Controller PCBs for LATL Models
Old software versus new software
Main Controller PCB identification for LATL outdoor units
This guide explains how to identify whether the Main Controller PCB installed in an LATL outdoor unit contains the old or new control software. Correct identification helps ensure the appropriate board and firmware revision are used during servicing, replacement and diagnostics.
Important: Always confirm both the EZ number and firmware marking before replacing a Main Controller PCB. Do not rely on the board code alone, as the old and new versions use the same board code.
1. Affected models
This guide applies to LATL series outdoor units, including:
- AOTG30LATL
- AOTG36LATL
- AOTG45LATL
- AOTG54LATL
- Related LATL capacities using the applicable Main Controller PCB
2. PCB identification overview
Each Main Controller PCB has an EZ number label and a software revision marking. These identifiers indicate whether the PCB contains the old or new control software.
Identification can be completed by checking:
- The EZ number on the white product label attached to the PCB.
- The firmware marking printed near the IC or EEPROM area.
3. Identification methods
A. Identify by EZ number
Locate the EZ number printed on the white product label fixed to the Main Controller PCB.
| PCB version | EZ number example | Description |
|---|---|---|
| Old software | EZ-343953 | Earlier control software version |
| New software | EZ-354482 | Updated software with revised sequence control and improved error detection |
Note: The EZ number may vary slightly by production batch. Confirm the identifying number sequence against the applicable technical information. The number may also be printed without a hyphen, for example EZ354482.
B. Identify by board label and firmware revision
The board code and firmware marking are typically printed 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 |
- A12 identifies the earlier firmware revision.
- A15 identifies the later firmware revision with updated control refinements.
- The board code K10BS-110HUE-C1 is common to both versions and cannot be used by itself to distinguish old from new software.
4. Software compatibility and replacement
Replacement control: Do not interchange an old-type PCB with a new-type PCB unless the required software and EEPROM data are updated together in accordance with the applicable technical procedure.
When updating from the old software to the new software:
- Confirm the replacement PCB version.
- Confirm the required firmware and EEPROM data.
- Complete the applicable ROM Writer procedure.
- Refer to the relevant technical bulletin before energising or commissioning the unit.
5. New PCB label example
K10BS-110HUE-C1 IC300_A15 EZ354482
This label identifies:
- Board code: K10BS-110HUE-C1
- New software revision: IC300_A15
- New-version EZ number: EZ354482
6. Quick identification summary
| Version | EZ number | Firmware marking |
|---|---|---|
| Old | EZ-343953 | IC300_A12 |
| New | EZ-354482 | IC300_A15 |
Key service point: Match the PCB software revision and required EEPROM data during replacement to reduce the risk of communication, startup or control-sequence issues.
Confirm the applicable service documentation, replacement-part information and technical bulletin before replacing or reprogramming the Main Controller PCB.