GE heat pump water heater displays F3 and may not run the heat pump compressor.

Safety: Shut off power at the breaker and verify power is off before servicing.

Steps to resolve F3:

• Access the heat pump section: Remove the upper cover to expose the evaporator coil and associated sensors.
• Locate the evaporator sensor: Look for a small probe clipped or taped to the evaporator coil tubing with a two-wire harness leading to the control board.
• Check mounting and condition: Ensure the sensor is firmly attached to the coil and not hanging loose. Inspect the harness for cuts, kinks, or melted insulation.
• Test resistance: Disconnect the sensor and measure resistance with a multimeter. Compare to the GE thermistor chart for the approximate coil temperature. Replace if open, shorted, or far out of range.
• Inspect the control board: If the sensor tests good, inspect the board for corrosion or burnt traces at the sensor connector. Reseat the connector.
• Restore power and test: Turn power back on and monitor for F3. If it reappears with a known-good sensor, the control board likely needs replacement.

Warning: Do not bend or puncture refrigerant tubing while working near the evaporator coil.