AJT040LCLCH - Main Control PCB DIP Switch Settings
J-IVS VRF Outdoor Unit | PCB Replacement & Configuration
When replacing the main control PCB on an AJT040LCLCH outdoor unit, the DIP switch configuration must be checked to ensure the replacement PCB is correctly configured.
This model belongs to the AIRSTAGE J-IVS series. Do not use switch settings from the earlier AJY040LCLAH J-IIS series, as the configurations differ.
1. Applicable Model
| Outdoor Model | AJT040LCLCH |
| Product Series | AIRSTAGE J-IVS |
| Equipment Type | VRF Heat Pump Outdoor Unit |
| Cooling Capacity | 12.1 kW |
| Heating Capacity | 12.1 kW |
2. Main Control PCB - DIP Switch Configuration
The following DIP switch positions have been supplied as the reference settings for the AJT040LCLCH outdoor unit.
When installing a replacement main control PCB, confirm the correct PCB part number and revision before applying the settings.
| DIP Switch | Switch 1 | Switch 2 | Switch 3 | Switch 4 |
|---|---|---|---|---|
| SET1 | ON | ON | ON | OFF |
| SET2 | OFF | OFF | OFF | ON |
| SET3 | OFF | OFF | OFF | OFF |
| SET4 | ON | OFF | OFF | OFF |
| SET5 | OFF | OFF | OFF | ON* |
The supplied configuration specifies SET5-4 = ON. This switch controls the communication network terminal resistor.
The terminal resistor must be configured according to the communication network arrangement. Confirm whether this outdoor unit requires termination before applying the ON setting.
These switch positions are provided as a model-specific reference supplied by Technical Support. They have not been independently cross-checked against the manufacturer's factory configuration chart. Always confirm compatibility with the replacement PCB part number and revision.
Quick Switch Reference
SET1: ON / ON / ON / OFF
SET2: OFF / OFF / OFF / ON
SET3: OFF / OFF / OFF / OFF
SET4: ON / OFF / OFF / OFF
SET5: OFF / OFF / OFF / ON (terminal resistor)
3. Identifying the PCB Switches
The outdoor main control PCB contains multiple DIP switch banks identified as SET1, SET2, SET3 and SET4, along with two rotary addressing switches identified as REF AD.
The SET5 switch bank may be located in another area of the PCB and should be identified using the applicable PCB layout documentation.
Main Control PCB
The main control PCB photograph identifies the switch banks and refrigerant circuit addressing controls.
DIP Switch Bank Identification
The close-up photograph shows the SET1-SET4 DIP switch banks and the REF AD rotary switches.
The REF AD rotary switches are used to configure the refrigerant circuit address. These must not be confused with the DIP switch configuration.
The required address depends on the installation and communication network configuration.
4. Main Control PCB Replacement Procedure
When replacing the outdoor main control PCB, follow the process below.
- Isolate the outdoor unit.
Disconnect and secure the electrical supply. Confirm the unit is de-energised and allow the required capacitor discharge period before accessing electrical components. - Confirm the correct replacement PCB.
Check the replacement PCB part number and revision against the model and spare parts documentation. - Record the original settings.
Where available, photograph and record the existing DIP switch positions and refrigerant circuit address. - Verify the DIP switch configuration.
Check SET1 through SET5 against the model-specific reference settings provided in Section 2. Confirm the factory configuration before making changes. - Check the terminal resistor.
Verify SET5-4 is correctly configured for the communication network. - Check REF AD addressing.
Confirm the correct refrigerant circuit address for the installed system. - Check electrical connections.
Ensure all connectors, communication wiring, earth connections and PCB plugs are correctly fitted. - Restore power and commission.
After verifying the configuration, restore power and carry out the required commissioning checks.
5. Verifying Connected Indoor Unit Capacity
Following the main control PCB replacement, the connected indoor unit capacity and communication network should be checked.
For applicable J-IVS systems, the outdoor PCB provides an indoor unit capacity and connection verification function using F3-12.
- Access the outdoor PCB function menu using the MODE / EXIT button.
- Navigate to F3 using SELECT and confirm using ENTER.
- Select function 12.
- Press and hold ENTER for approximately 3 seconds or as specified in the service manual.
- Wait for the connected indoor unit check to complete.
- Confirm the detected number of indoor units matches the installation.
- Verify the reported connected capacity ratio against the approved system design.
- Confirm a successful result. Investigate any displayed errors before returning the system to service.
The connected-capacity check verifies the detected indoor unit network and its capacity. It does not replace the requirement to verify the correct replacement PCB DIP switch settings.
6. Troubleshooting After PCB Replacement
| Issue | Recommended Check |
|---|---|
| Incorrect unit configuration | Confirm replacement PCB compatibility and verify SET1-SET4 configuration against approved model-specific information. |
| Indoor units not detected | Check REF AD addressing, transmission wiring, network termination and communication connections. |
| Communication fault | Verify the terminal resistor setting, network wiring and absence of duplicate refrigerant circuit addresses. |
| Capacity check fails | Confirm connected indoor unit quantity, capacity ratio, addressing and communication integrity. |
| Incorrect PCB installed | Confirm the PCB part number and revision are approved for AJT040LCLCH. |
7. Further Technical Assistance
If the correct DIP switch configuration cannot be confirmed, or the unit continues to experience faults following PCB replacement, contact General Technical Support.
Please provide:
- Outdoor unit model and serial number.
- Original and replacement PCB part numbers and revisions.
- Photographs of DIP switch positions.
- REF AD addressing configuration.
- Connected indoor unit models and quantities.
- Any error codes displayed following PCB replacement.
8. Related Technical References
AJT040LCLCH - Product Information
VRF Main Control PCB Replacement Procedure
GENERAL AIRSTAGE | TECHNICAL SUPPORT
This information is intended for qualified HVAC service technicians. Always refer to the applicable manufacturer service documentation and approved replacement PCB configuration before undertaking electrical or control system modifications.