DIY HVAC Tools

Thermal Zone mini split error codes

Thermal Zone (International Refrigeration Products) sells its Sea Breeze mini splits through HVAC supply houses. They are Midea-built and use the Midea code set.

Covers: Sea Breeze 16 to 19 SEER single-zone (9H49YIMI, 12H49ZIMI, 18H49ZIMI, 24H47ZIMI…).

Type it exactly as the unit shows it. Not sure which brand? It is printed on the front of the indoor unit.

Most looked-up Thermal Zone codes

E1Communication error between indoor and outdoor unitsE5Evaporator coil temperature sensor (T2) open or short circuitECRefrigerant leak detected (low refrigerant charge)P4Inverter compressor drive errorF1Outdoor ambient temperature sensor (T4) open or short circuitE4Indoor room temperature sensor (T1) open or short circuit

All Thermal Zone codes

25 codes. Type to filter the list.

CodeMeaningTypeFix
E0Indoor unit EEPROM parameter errorFaultDIY checks
E1Communication error between indoor and outdoor unitsFaultDIY checks
E2Zero-crossing signal detection errorFaultDIY checks
E3Indoor fan speed out of control (indoor fan motor fault)FaultDIY checks
E4Indoor room temperature sensor (T1) open or short circuitFaultDIY checks
E5Evaporator coil temperature sensor (T2) open or short circuitFaultDIY checks
ECRefrigerant leak detected (low refrigerant charge)FaultDIY checks
F0Overload current protection (compressor over-current)ProtectionDIY checks
EBCommunication error between indoor main board and display boardFaultDIY checks
EFIntelligent eye (occupancy sensor) module errorFaultDIY
F1Outdoor ambient temperature sensor (T4) open or short circuitFaultDIY checks
F2Condenser coil temperature sensor (T3) open or short circuitFaultDIY checks
F3Compressor discharge temperature sensor (TP) open or short circuitFaultDIY checks
F4Outdoor unit EEPROM parameter errorFaultTechnician
F5Outdoor fan speed out of control (outdoor fan motor fault)FaultDIY checks
P0Inverter module (IPM) malfunctionProtectionTechnician
P1Over-voltage or under-voltage protectionProtectionDIY checks
P2High temperature protection (compressor top or inverter module)ProtectionDIY checks
P3Outdoor temperature too low protection (heating lockout)ProtectionDIY
P4Inverter compressor drive errorProtectionTechnician
P5Mode conflict (multi-zone)ProtectionDIY
P6Outdoor low pressure protectionProtectionDIY checks
dFDefrost cycle runningStatusDIY
CLFilter cleaning reminderStatusDIY
APWi-Fi pairing (access point) modeStatusDIY

How Thermal Zone shows error codes

The code appears on the indoor unit's LED display in place of the set temperature. Some models also blink the indicator lamps in a pattern that matches the code. E codes are faults in the indoor unit or its communication link, F codes are faults on the outdoor side, and P codes are protections: the outdoor unit has stopped itself to prevent damage. EC is the refrigerant leak check.

Brands built on the same platform

These brands share a code table with Thermal Zone because the same factory builds them, so their pages describe the same faults: ACiQ, AirEase, Arcoaire, Arctic King, Armstrong Air, Blueridge, Bosch, Bryant, Carrier, Comfortmaker, Concord, Day & Night, Della, Ducane.

Sources

  • Thermal Zone Single Zone Minisplit Service Manual 953-0134 (2021), error code table

Updated September 2026. Manufacturer site: irproducts.biz