E7
Day & Night
Mode Conflict / Indoor Fan or Reversing Valve Control Error (Heat Pump Models)
E7 error, unit may start and stop frequently, poor cooling performance
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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 thermostat wiring (O/B reversing valve signal), Stuck reversing valve on heat pump, Faulty indoor fan relay on PCB, Software conflict between indoor and outdoor mode commands
How to Fix / Troubleshooting
Safety first: Turn OFF power to both indoor and outdoor units before accessing wiring or boards.
- Step 1 – Verify thermostat settings: Ensure the thermostat is correctly configured for a Day & Night heat pump (O or B setting as required). Incorrect configuration can cause mode conflicts.
- Step 2 – Check thermostat wiring: At the air handler control board, confirm the O/B wire is on the correct terminal and matches the thermostat terminal. Tighten any loose screws.
- Step 3 – Observe operation: Restore power and call for cooling, then heating. Listen for the reversing valve solenoid click at the outdoor unit when switching modes. If no change is heard, the valve or its coil may be faulty.
- Step 4 – Inspect indoor fan relay: If the indoor fan cycles erratically with E7, the fan relay on the indoor PCB may be sticking, requiring board replacement.
- Professional service: Reversing valve diagnostics and replacement involve refrigerant handling and must be done by a licensed HVAC technician.
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Repair Difficulty
Hard
4/5
Required Part
Reversing Valve Coil (Heat Pump)
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