F4 error, compressor cycles rapidly or will not start in heat mode

Safety first: Unplug the unit before accessing the compressor compartment. The reversing valve is part of the sealed refrigerant circuit—do not attempt to open it.

• Step 1 – Listen for valve operation:
  • Switch between COOL and HEAT modes with the unit running.
  • You should hear a distinct click or whoosh from the reversing valve area.
• Step 2 – Check coil connection:
  • Access the compressor compartment and locate the Reversing Valve Coil on the valve body.
  • Ensure the electrical connector is firmly attached and wires are not damaged.
• Step 3 – Test coil:
  • With power disconnected, measure coil resistance; an open circuit indicates a failed coil.
  • Replace the coil with a compatible Pro Breeze Reversing Valve Coil if defective.

If the valve body itself is stuck or leaking, a licensed HVAC technician must replace and re-braze the valve and recharge the system.