Carrier error code E4
What it means
Compressor discharge temperature protection.
Possible causes
High discharge temperature from poor condenser cooling Low refrigerant mass flow Non-condensables or incorrect refrigerant charge
Suggested fix
Assess condenser airflow and cleanliness, confirm the correct refrigerant type and charge amount and measure discharge-line temperature; address the identified issue before clearing the error and restarting the compressor.
Safety first. Isolate the power supply before inspecting any unit. Refrigerant-circuit
and electrical repairs must be carried out by a qualified, registered technician.
Other Carrier codes
- E1 — High pressure protection in the refrigeration circuit.
- E2 — Evaporator coil temperature sensor fault.
- E3 — Low pressure protection.
- E5 — Overcurrent or overload protection.
- E6 — Communication error between indoor and outdoor units.
- EC — Refrigerant leak detection alarm.
- F0 — Low refrigerant protection.
- P0 — High voltage protection.
- P1 — Low voltage protection.
- P4 — Fan speed fault.