Unit displays E3 and may stop cooling or shut down unexpectedly.

Safety: Unplug the AC. If it is a window or through-the-wall unit, be careful when moving it; the rear section is heavy.

• Access the rear section: For window and through-the-wall Soleus Air units, remove the outer case to expose the condenser coil (rear coil). For portable units, remove the side or rear panel as per the user manual.
• Locate the condenser sensor: Find the small probe clipped to the condenser coil tubing or fins, usually near the middle of the coil, with two wires leading to the control board.
• Check mounting: Ensure the sensor is firmly clipped to the coil. If loose, reattach it securely so it senses coil temperature correctly.
• Inspect wiring and connector: Trace the wires back to the PCB. Look for chafed insulation, burn marks, or loose connectors. Reseat the plug on the board.
• Measure resistance: With the sensor unplugged and the unit powered off, measure resistance and compare to the Soleus Air temperature-resistance chart. Replace if open, shorted, or far out of spec.
• Install replacement: Use a Soleus Air-compatible condenser thermistor. Clip it to the same location on the coil and secure the wiring with cable ties away from the fan blade.
• Reassemble and test: Reinstall the cabinet, plug in, and run the unit. The E3 code should clear if the sensor circuit is restored.