E4
MrCool Compressor Discharge High Temperature Protection

Indoor unit displays E4 and stops; may occur during heating mode on heat pump models.

Advertisements

Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

Advertisements

Possible Causes

Low refrigerant charge, Blocked outdoor coil, Outdoor fan not running or intermittent, Overload on compressor due to high ambient temperature

How to Fix / Troubleshooting

Safety first: Shut off power at the outdoor disconnect before touching the outdoor unit.

Steps:

  • Clean outdoor coil: Remove leaves and debris. Gently hose off the condenser coil fins.
  • Check outdoor fan: Restore power and observe startup. If the outdoor fan motor fails to start with the compressor or stops randomly, shut power off and schedule replacement.
  • Check sun and clearance: Ensure the outdoor unit has shade if possible and adequate airflow clearance. Avoid enclosing the unit.

Technician tasks: Persistent E4 may indicate low refrigerant, a failing discharge temperature sensor, or compressor issues. These require professional diagnosis with proper tools.

Advertisements

Repair Difficulty

Hard 4/5

Required Part

Outdoor Fan Motor
Check Price on Amazon

We may earn a commission from links on this page.

Advertisements