HVAC · supported

Daikin

ModbusBACnetMQTT

Daikin is the world's largest manufacturer of air-conditioning equipment, with VRV/VRF systems used in offices, hotels, and large residences worldwide. HVAC API exposes Daikin temperature, setpoint, and operating-mode controls via a unified HTTP endpoint, abstracting over Modbus, BACnet, and Daikin's own cloud API so integrators can drive Daikin equipment without learning each transport.

Device families

VRV/VRF Systems
4 endpoints
Split AC
2 endpoints

Endpoints & snippets

VRV/VRF Systems

GET /v1/devices/{id}/temperature
POST /v1/devices/{id}/setpoint
GET /v1/devices/{id}/mode
POST /v1/devices/{id}/mode

curl -H "Authorization: Bearer $HVACAPI_KEY" \
  https://api.hvacapi.com/v1/devices/{device_id}/temperature

Split AC

GET /v1/devices/{id}/temperature
POST /v1/devices/{id}/setpoint

Fault codes & error codes

20 codes documented for Daikin. Confirm against your model's service manual — some codes vary between product lines (VRV vs. Sky Air vs. residential split, etc.).

Code	Category	Meaning	Suggested action	Severity	Help
A0	Indoor unit	External protection device activatedAsk AI to troubleshoot →	Check the indoor unit's connected protection device (float switch, etc.) and reset.	critical	Ask AI →
A1	Indoor unit	Indoor unit PCB defectAsk AI to troubleshoot →	Replace the indoor unit PCB.	critical	Ask AI →
A6	Indoor unit	Indoor fan motor malfunctionAsk AI to troubleshoot →	Inspect fan motor wiring, capacitor, and motor itself.	critical	Ask AI →
E1	Outdoor unit	Outdoor PCB defectAsk AI to troubleshoot →	Replace outdoor unit main PCB.	critical	Ask AI →
E5	Outdoor unit	Inverter compressor motor lockAsk AI to troubleshoot →	Power-cycle; if persistent, check compressor windings and inverter board.	critical	Ask AI →
E6	Outdoor unit	Compressor overcurrentAsk AI to troubleshoot →	Inspect for refrigerant overcharge, condenser airflow, and compressor health.	critical	Ask AI →
E7	Outdoor unit	Outdoor fan motor lockAsk AI to troubleshoot →	Inspect outdoor fan motor and capacitor; check for physical obstruction.	critical	Ask AI →
F6	Outdoor unit	High-pressure protectionAsk AI to troubleshoot →	Check condenser airflow, refrigerant overcharge, and HPS sensor.	critical	Ask AI →
L5	Outdoor unit	Inverter compressor overcurrent (instant)Ask AI to troubleshoot →	Inspect compressor windings, inverter, and DC bus.	critical	Ask AI →
U0	System	Refrigerant shortageAsk AI to troubleshoot →	Pressure-test for leaks; recover, evacuate, and recharge per nameplate.	critical	Ask AI →
U4	System	Indoor↔outdoor communication errorAsk AI to troubleshoot →	Verify F1/F2 wiring polarity and continuity; check for shielded-cable termination.	critical	Ask AI →
UA	System	Indoor/outdoor unit combination mismatchAsk AI to troubleshoot →	Confirm indoor and outdoor model compatibility on the system selection chart.	critical	Ask AI →
A3	Indoor unit	Drain water level abnormalAsk AI to troubleshoot →	Inspect drain pump, float switch, and drain piping for blockage.	warning	Ask AI →
A5	Indoor unit	Heat exchanger freeze-up / high-temperature protectionAsk AI to troubleshoot →	Check airflow over the indoor coil, filter cleanliness, and refrigerant charge.	warning	Ask AI →
C4	Indoor unit	Indoor heat-exchanger thermistor abnormalAsk AI to troubleshoot →	Check thermistor resistance and replace if out of spec.	warning	Ask AI →
C9	Indoor unit	Suction-air thermistor abnormalAsk AI to troubleshoot →	Check thermistor resistance and connector.	warning	Ask AI →
F3	Outdoor unit	Discharge-pipe temperature controlAsk AI to troubleshoot →	Verify refrigerant charge and expansion valve operation.	warning	Ask AI →
H3	Outdoor unit	High-pressure switch malfunctionAsk AI to troubleshoot →	Inspect HPS continuity and replace if open at rest.	warning	Ask AI →
L4	Outdoor unit	Inverter heat-sink temperature highAsk AI to troubleshoot →	Clean inverter heat sink fins; verify outdoor airflow.	warning	Ask AI →
U2	System	Power-supply voltage abnormalAsk AI to troubleshoot →	Verify supply voltage within nameplate tolerance; check phase rotation on 3φ.	warning	Ask AI →

Daikin

Device families

Endpoints & snippets

Fault codes & error codes

External resources