Unit displays E7 and will not operate in certain modes

Safety: Turn OFF power at the breaker before accessing the outdoor or compressor compartment.

Steps to check E7:

• Confirm mode selection: Ensure the remote or front panel is not commanding conflicting modes (e.g., simultaneous heat and cool on multi-zone systems). Reset the unit to OFF, then select a single mode (COOL or HEAT).
• Listen for valve operation: When switching between HEAT and COOL, you should hear a distinct click from the reversing valve coil in the outdoor section.
• Inspect reversing valve coil: Access the outdoor compartment and locate the 4-way reversing valve and its solenoid coil. Check that the coil is firmly seated and wiring is intact.
• Check coil resistance: With power off, disconnect the coil and measure resistance. An open circuit (OL) indicates a failed coil that must be replaced.
• Check wiring and board output: Verify that the control board is sending the correct voltage to the coil when changing modes (this is typically done by a technician).
• Mechanical valve issues: If the coil is good and powered but the system does not switch modes, the valve may be mechanically stuck, requiring professional replacement and refrigerant handling.

Note: Reversing valve replacement involves opening the refrigerant circuit and must be performed by an EPA-certified technician.