An error code is a way for an HVAC system (like a mini-split or central unit) to communicate that something isn’t working properly.
Instead of just shutting down with no explanation, the system will flash a specific code — usually letters and numbers — on a display or indicator light.
Each error code points to a specific issue, like:
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Electrical problems
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Sensor malfunctions
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Communication failures between components
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Refrigerant pressure issues
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Motor faults
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Temperature problems
1st Gen Condensers and Heat Pump Condensers:
| AC Condenser | Heat Pump Condenser |
| HAC14018 | HHP14018 |
| HAC14024 | HHP14024 |
| HAC14030 | HHP14030 |
| HAC14036 | HHP14036 |
| HAC14042 | HHP14042 |
| HAC14048 | HHP14048 |
| HAC14060 | HHP14060 |
Diagnostic Codes:
| Error Code | Display | Description |
| Green Light Flashes Yellow Lights💥 | Green Light Slowly Flashing | Normal Standby |
| Green Light Flashes Yellow Lights💥 | Green Light Normally On | Normal Operation |
| Green Light or Yellow Light Slowly Flashing💥 | Yellow Light Flashes 2 Times Every 8 Seconds | (T3) Temperature Sensor Fault |
| Green Light or Yellow Light Slowly Flashing💥 | Yellow Light Flashes 8 Times Every 8 Seconds | (T5) Temperature Sensor Fault |
| Green Light or Yellow Light Slowly Flashing💥 | Yellow Light Flashes 6 Times Every 8 Seconds | Low Air Pressure Alarm |
| Green Light or Yellow Light Slowly Flashing💥 | Yellow Light Flashes 1 Time Every 8 Seconds | High Pressure Alarm |
| Green Light or Yellow Light Slowly Flashing💥 | Yellow Light Flashes 9 Times Every 8 Seconds | (T3) High Temperature Protection |
| Green Light or Yellow Light Slowly Flashing💥 | Yellow Light Flashes 5 Times Every 8 Seconds | High Exhaust Temperature Protection |
| Green Light Goes Off and Yellow Light is On | High/Low Voltage Protection in 20 Minutes | Turn Off Power for 10-15 Minutes and Restart |
| Green Light Goes Off and Yellow Light is On | Exhaust Temperature is Too High- 3 Times Within 20 Minutes | Turn Off Power for 10-15 Minutes and Restart |
| Green Light Goes Off and Yellow Light is On | (T3) High Temperature Protection 3 Times Within 20 Minutes | Turn Off Power for 10-15 Minutes and Restart |
1st Gen Air Handlers:
| Model |
| HAH14018 |
| HAH14024 |
| HAH14030 |
| HAH14036 |
| HAH14042 |
| HAH14048 |
| HAH14060 |
Diagnostic Codes:
| Error Code Display | Description |
| Green Light Always On | Normal Operation |
| Red Light Always On | Evaporator Temperature Sensor (T2) Failure |
| Green Light On & Yellow Light Flashing💥 | Evaporator High & Low Temperature Protection |
| Green Light Flashing💥 | System is in Normal Operating Status |
・・・──────────────────────────────・・・
2nd Gen Condensers and Heat Pump Condensers:
| AC Condenser | Heat Pump Condenser |
| HHP15018 | HAC15018 |
| HHP15024 | HAC15024 |
| HHP15030 | HAC15030 |
| HHP15036 | HAC15036 |
| HHP15042 | HAC15042 |
| HHP15048 | HAC15048 |
| HHP15060 | HAC15060 |
Diagnostic Codes:
| Error Code | Display | Description |
| Yellow Light Off | Green Light Flashing Slow | Unit Standby |
| Yellow Light Off | Green Light On | Unit is Running |
| 1 Flash💥 | Yellow light flash 1 time for every 8s | T3 temperature sensor error |
| 2 Flashes💥 | Yellow light flash 2 time for every 8s | T4 temperature sensor error |
| 3 Flashes💥 | Yellow light flash 3 time for every 8s | T5 temperature sensor error |
| 4 Flashes💥 | Yellow light flash 4 time for every 8s | Low pressure protection |
| 5 Flashes💥 | Yellow light flash 5 time for every 8s | High pressure protection |
| 6 Flashes💥 | Yellow light flash 6 time for every 8s | T3 high temperature protection |
| 7 Flashes💥 | Yellow light flash 7 time for every 8s | T5 high temperature protection |
| 8 Flashes💥 | Yellow light flash 8 times for every 8s (Only for DC fan motor) |
Fan motor feedback error |
| 9 Flashes💥 | Yellow light flash 9 times for every 8s | TH temperature sensor error |
| 4 Flashes💥 | Yellow light flash 4 times for every 8s | Low pressure protection occur 6 times within 60 mins. |
| 5 Flashes💥 | Yellow light flash 5 times for every 8s | High pressure protection occur 6 times within 60 mins. |
| 6 Flashes💥 | Yellow light flash 6 times for every 8s | T3 high temperature protection occur 6 times within 60 mins. |
| 7 Flashes💥 | Yellow light flash 7 times for every 8s | T5 high temperature protection occur 3 times within 20 mins. |
| 8 Flashes💥 | Yellow light flash 8 times for every 8s | Fan motor feedback error occur 3 times within 20 minutes |
| 9 Flashes💥 | Yellow light flash 9 times for every 8s | Refrigerant leakage protection |
2nd Gen Air Handlers:
| Model |
| HAH15018 |
| HAH15024 |
| HAH15030 |
| HAH15036 |
| HAH15042 |
| HAH15048 |
| HAH15060 |
Diagnostic Codes:
| Error Code Display | Description |
| Green light always on | No system alarm and error, normal standby |
| Red light always on | Evaporator temperature sensor (T2) failure |
| Green light always on & yellow light flashing💥 |
Evaporator high and low temperature protection |
| Green light flashing💥 | System is in normal operating status |
・・・──────────────────────────────・・・
3rd Gen 15 SEER AC Condenser:
| Model |
| HAC15018FA |
| HAC15024FA |
| HAC15030FA |
| HAC15036FA |
| HAC15042FA |
| HAC15048FA |
| HAC15060FA |
Diagnostic Codes of Motor Driver Module:
| Error Code Display (LED 1) | Description |
| Steady On | Normal Operation |
| OFF | Power Supply Failure |
| Keep Flashing- 2s On then 2s Off💥 |
Standby |
| Keep Flashing- 0.2s On then 0.2s Off💥 |
Inter-Integrated Circuit Communication Error |
| 1 Flash/Cycle💥 | Motor Current Error |
| 2 Flash/Cycle💥 | Inverter Module Temperature Error |
| 3 Flash/Cycle💥 | DC Bus Voltage Error |
| 4 Flash/Cycle💥 | Motor Parameter Error |
| 5 Flash/Cycle💥 | Motor Startup Failure |
| 6 Flash/Cycle💥 | Phase Sequence Error |
Diagnostic Codes of Main Control Module:
| Error Code Display (LED 2) | Description |
| Steady On | Normal Operation |
| OFF | Power Supply Failure |
| 1 Flash/Cycle💥 | T3 Sensor Failure |
| 2 Flash/Cycle💥 | T4 Sensor Failure |
| 3 Flash/Cycle💥 | LPC Open |
| 5 Flash/Cycle💥 | OFM Failure |
| 6 Flash/Cycle💥 | No Machine Type |
・・・────────────────・・・
3rd Gen 13 SEER AC Condenser:
| Model |
| HAC13018FA |
| HAC13024FA |
| HAC13030FA |
| HAC13036FA |
| HAC13042FA |
| HAC13048FA |
| HAC13060FA |
Diagnostic Codes of Motor Driver Module:
| Error Code Display (LED 1) | Description |
| Steady On | Normal Operation |
| OFF | Power Supply Failure |
| Keep Flashing- 2s On then 2s Off💥 |
Standby |
| Keep Flashing- 0.2s On then 0.2s Off💥 |
Inter-Integrated Circuit Communication Error |
| 1 Flash/Cycle💥 | Motor Current Error |
| 2 Flash/Cycle💥 | Inverter Module Temperature Error |
| 3 Flash/Cycle💥 | DC Bus Voltage Error |
| 4 Flash/Cycle💥 | Motor Parameter Error |
| 5 Flash/Cycle💥 | Motor Startup Failure |
| 6 Flash/Cycle💥 | Phase Sequence Error |
Diagnostic Codes of Main Control Module:
| Error Code Display (LED 2) | Description |
| Steady On | Normal Operation |
| OFF | Power Supply Failure |
| 1 Flash/Cycle💥 | T3 Sensor Failure |
| 2 Flash/Cycle💥 | T4 Sensor Failure |
| 3 Flash/Cycle💥 | LPC Open |
| 5 Flash/Cycle💥 | OFM Failure |
| 6 Flash/Cycle💥 | No Machine Type |
・・・────────────────・・・
15 SEER2 Heat Pump Condenser:
| Model |
| HHP15018FA |
| HHP15024FA |
| HHP15030FA |
| HHP15036FA |
| HHP15042FA |
| HHP15048FA |
| HHP15060FA |
Diagnostic Codes of Motor Driver Module:
| Error Code Display (LED 1) | Description |
| Steady On | Normal Operation |
| OFF | Power Supply Failure |
| Keep Flashing- 2s On then 2s Off💥 |
Standby |
| Keep Flashing- 0.2s On then 0.2s Off💥 |
Inter-Integrated Circuit Communication Error |
| 1 Flash/Cycle💥 | Motor Current Error |
| 2 Flash/Cycle💥 | Inverter Module Temperature Error |
| 3 Flash/Cycle💥 | DC Bus Voltage Error |
| 4 Flash/Cycle💥 | Motor Parameter Error |
| 5 Flash/Cycle💥 | Motor Startup Failure |
| 6 Flash/Cycle💥 | Phase Sequence Error |
Diagnostic Codes of Main Control Module:
| Error Code Display (LED 2) | Description |
| Steady On | Normal Operation |
| OFF | Power Supply Failure |
| 1 Flash/Cycle💥 | T3 Sensor Failure |
| 2 Flash/Cycle💥 | T4 Sensor Failure |
| 3 Flash/Cycle💥 | LPC Open |
| 5 Flash/Cycle💥 | OFM Failure |
| 6 Flash/Cycle💥 | No Machine Type |
✅ Why Error Codes Matter:
They help technicians, and installers quickly understand where to start troubleshooting without guessing.
✅ Important Tip:
While error codes point you in the right direction, they don’t always tell you the exact part that’s failed — just the general area or type of problem. Further testing is often needed!
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