E7
Carrier
Mode Conflict / Indoor-Outdoor Mismatch or Reversing Valve Error
Indoor unit displays E7 and outdoor unit does not operate
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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.
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Possible Causes
Incorrect wiring between indoor and outdoor units, Faulty 4-way reversing valve coil, Indoor units calling for different modes on multi-split system, Control PCB logic fault
How to Fix / Troubleshooting
Safety: Turn OFF power to both indoor and outdoor units before checking wiring.
- Step 1 – Confirm system type: If you have a multi-split Carrier system with multiple indoor units, ensure all indoor units are set to the same mode (all cooling or all heating). Mixed modes can trigger E7.
- Step 2 – Check wiring: At both indoor and outdoor terminal blocks, verify that the control wires are correctly matched (e.g., 1–2–3 or S1–S2–S3). Correct any miswiring.
- Step 3 – Power reset: Turn OFF the breaker for 5 minutes, then restore power and test again.
- Step 4 – Technician diagnosis: If E7 persists, a technician should test the reversing valve coil and control PCB outputs to ensure proper mode switching.
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Repair Difficulty
Hard
4/5
Required Part
4-Way Reversing Valve Coil
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