Unit stops and displays E3, may occur during heating or cooling on heat pump models

Safety: Turn OFF power at the breaker or disconnect. Outdoor sections may have sharp metal and moving fan blades.

Steps to resolve E3:

• Access outdoor section: For Friedrich PTAC and ductless systems, remove the outdoor access panel or sleeve cover to expose the condenser coil and fan area.
• Locate condenser sensor: Look for a small thermistor clipped to the condenser coil tubing or mounted on a bracket near the coil.
• Inspect sensor and clip: Ensure the sensor is firmly attached to the coil. If it has fallen off or is dangling, reattach it using the original clip or a new clip from the replacement kit.
• Check wiring harness: Follow the sensor wires back to the control board. Look for chafing where the wires pass through metal bulkheads. Repair or replace damaged wiring and secure with grommets or cable ties.
• Test sensor: Disconnect and measure resistance at ambient temperature. Compare to the Friedrich service chart. Replace the sensor if readings are open, shorted, or far out of spec.
• Reassemble and test: After replacing or reseating the sensor, restore power and run the unit. If E3 persists, suspect a faulty main control board.

Warning: Do not attempt to open the sealed refrigeration system. Sensor replacement does not require opening refrigerant lines.