E4 — Compressor air discharge high temperature protection

What does E4 mean?

The compressor discharge temperature has exceeded 239°F, causing the unit to stop for protection. This error is shown as 'E4' on the ODU main board LED display.

• Service valve of the outdoor unit (ODU) is not fully opened
• Abnormal electronic expansion valve
• Outdoor or indoor fan not working properly
• Blocked indoor unit filter or air duct (during cooling mode)
• Ambient temperature exceeds allowable operation range
• System is undercharged with refrigerant
• Refrigerant lines are blocked

Click steps to track your progress.

1. 1

   Ensure the outdoor unit service valve is fully opened.

2. 2

   Check if the indoor unit filter or air duct is blocked.

3. 3

   Verify that the indoor and outdoor unit capacities match.

4. 4

   Confirm the ambient temperature is within the unit's operating range.

5. 5

   If problems persist, check for refrigerant leaks, blockages, or fan issues. Contact support.