Indoor unit displays F9, unit may not operate in certain modes

Safety first: Turn off power at the outdoor disconnect. The four-way valve is part of the sealed refrigerant circuit; do not attempt to open it.

• Check coil connection: Locate the four-way valve coil on the reversing valve body. Ensure its electrical connector is firmly attached.
• Coil resistance: A technician can measure coil resistance; an open circuit indicates a failed coil that must be replaced.
• Mode test: With power restored, switch between heating and cooling and listen for a distinct click from the valve. No click may indicate a stuck valve or failed coil/PCB.
• Repairs: Replace the four-way valve coil if open or shorted. If the valve itself is stuck or leaking, a technician must recover refrigerant, replace the valve, evacuate, and recharge.