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:
-
Electrical problems
-
Sensor malfunctions
-
Communication failures between components
-
Refrigerant pressure issues
-
Motor faults
-
Temperature problems
2nd Gen Heat Pump Upflow:
| Model |
| GCHPV024TGTANXL |
| GCHPV036TGTANXL |
| GCHPV048TGTANXL |
| GCHPV060TGTANXL |
| GCHPV024TGTANXR |
| GCHPV036TGTANXR |
| GCHPV048TGTANXR |
|
GCHPV060TGTANXR |
Diagnostic Codes:
| Error Code | Description |
| Blue Light | Power |
| Green Light | System Active |
| Red Light | High Pressure Limit |
| Red Light | Low Pressure Limit |
| Red Light | Freeze Protection |
| Red Light | Condensate Fault |
・・・──────────────────────────────・・・
2nd Gen Heat Pump Horizontal:
| Model |
| GCHPH024TGTANXL |
| GCHPH036TGTANXL |
| GCHPH048TGTANXL |
| GCHPH060TGTANXL |
| GCHPH024TGTANXR |
| GCHPH036TGTANXR |
| GCHPH048TGTANXR |
| GCHPH060TGTANXR |
Diagnostic Codes:
| Error Code | Description |
| Blue Light | Power |
| Green Light | System Active |
| Red Light | High Pressure Limit |
| Red Light | Low Pressure Limit |
| Red Light | Freeze Protection |
| Red Light | Condensate Fault |
・・・──────────────────────────────・・・
2nd Gen Heat Pump Downflow:
| Model |
| GCHPD024TGTANXL |
| GCHPD036TGTANXL |
| GCHPD048TGTANXL |
| GCHPD060TGTANXL |
| GCHPD024TGTANXR |
| GCHPD036TGTANXR |
| GCHPD048TGTANXR |
| GCHPD060TGTANXR |
Diagnostic Codes:
| Error Code | Description |
| Blue Light | Power |
| Green Light | System Active |
| Red Light | High Pressure Limit |
| Red Light | Low Pressure Limit |
| Red Light | Freeze Protection |
| Red Light | Condensate Fault |
・・・──────────────────────────────・・・
Inverter Series Compressor:
| Model |
| GCSHPM048IN |
| GCSHPM060IN |
Diagnostic Codes:
| Error Code | Description |
| E1 | High-pressure protection |
| E2 | Anti-freeze protection |
| E3 | Low-pressure protection |
| E4 | High Discharge Temperature Protection |
| EC | Water Flow Switch Protection |
| C6 | Discharge temperature sensor error |
| dc | Suction temperature sensor error |
| FB | Water inlet temperature sensor error |
| FM | Water outlet temperature sensor error |
| A7 | Liquid pipe temperature sensor error |
| E0 | Fan Error |
| C2 | In-Tube Temperature Sensor Error |
| Cb | Gas Pipe Temperature Sensor Error |
| C1 | Return Air Temperature Sensor Error |
| E6 | Communication error |
| LF | Power protection |
| E5 | Current protection |
| H5 | IPM protection |
| HC | PFC protection |
| P8 | High Driver Module Temperature Protection |
| PL | DC Bus Under-Voltage Protection or DC Bus Voltage Drop Error |
| PH | DC Bus Over-Voltage Protection |
| PU | Charging Circuit Error |
| C9 | Chip error |
| H3 | High-pressure sensor error |
| LP | Capacity DIP Switch Setting Error |
・・・──────────────────────────────・・・
Inverter Series Multi-Positional Coil:
| Model |
| GCSCAM048GN |
| GCSCAM060GN |
Diagnostic Codes:
| Error Code | Description |
| E1 | High-pressure protection |
| E2 | Anti-freeze protection |
| E3 | Low-pressure protection |
| E4 | High Discharge Temperature Protection |
| EC | Water Flow Switch Protection |
| C6 | Discharge temperature sensor error |
| dc | Suction temperature sensor error |
| FB | Water inlet temperature sensor error |
| FM | Water outlet temperature sensor error |
| A7 | Liquid pipe temperature sensor error |
| E0 | Fan Error |
| C2 | In-Tube Temperature Sensor Error |
| Cb | Gas Pipe Temperature Sensor Error |
| C1 | Return Air Temperature Sensor Error |
| E6 | Communication error |
| LF | Power protection |
| E5 | Current protection |
| H5 | IPM protection |
| HC | PFC protection |
| P8 | High Driver Module Temperature Protection |
| PL | DC Bus Under-Voltage Protection or DC Bus Voltage Drop Error |
| PH | DC Bus Over-Voltage Protection |
| PU | Charging Circuit Error |
| C9 | Chip error |
| H3 | High-pressure sensor error |
| LP | Capacity DIP Switch Setting Error |
・・・──────────────────────────────・・・
Inverter Series Air Return:
| Model |
| GCSAR048060 |
Diagnostic Codes:
| Error Code | Description |
| E1 | High-pressure protection |
| E2 | Anti-freeze protection |
| E3 | Low-pressure protection |
| E4 | High Discharge Temperature Protection |
| EC | Water Flow Switch Protection |
| C6 | Discharge temperature sensor error |
| dc | Suction temperature sensor error |
| FB | Water inlet temperature sensor error |
| FM | Water outlet temperature sensor error |
| A7 | Liquid pipe temperature sensor error |
| E0 | Fan Error |
| C2 | In-Tube Temperature Sensor Error |
| Cb | Gas Pipe Temperature Sensor Error |
| C1 | Return Air Temperature Sensor Error |
| E6 | Communication error |
| LF | Power protection |
| E5 | Current protection |
| H5 | IPM protection |
| HC | PFC protection |
| P8 | High Driver Module Temperature Protection |
| PL | DC Bus Under-Voltage Protection or DC Bus Voltage Drop Error |
| PH | DC Bus Over-Voltage Protection |
| PU | Charging Circuit Error |
| C9 | Chip error |
| H3 | High-pressure sensor error |
| LP | Capacity DIP Switch Setting Error |
✅ Why Error Codes Matter:
They help technicians, installers, and even homeowners 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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