Indoor unit stops and displays E1; cooling or heating stops shortly after startup.

Safety first: Turn off the air conditioner at the breaker and unplug (if plug-in type) before opening the indoor unit. Use an insulated screwdriver and avoid touching live terminals.

Steps to check and correct:

• 1. Power reset: Turn off power for 5 minutes, then restore. If E1 clears temporarily but returns, continue with hardware checks.
• 2. Access the indoor PCB: Open the front cover, remove the air filters, and remove the plastic front panel screws to expose the control box cover. Remove the control box cover.
• 3. Locate the room sensor: Find the small NTC sensor (usually in front of the evaporator coil or in the air intake) with two thin wires going to the PCB, often labeled RT or Room NTC.
• 4. Check connections: Ensure the sensor plug is fully seated on the PCB and that the wires are not cut, pinched, or corroded. Reseat the connector several times to clean contacts.
• 5. Measure resistance: With power still OFF, disconnect the sensor and measure resistance with a multimeter. At about 25°C, most Airwell NTCs read around 5–15 kΩ (check service manual if available). If reading is open (OL) or near 0 Ω, the sensor is defective.
• 6. Replace sensor if faulty: Order a compatible Airwell indoor room temperature sensor (match by model number). Clip or slide the new sensor into the original location and route wires away from sharp metal edges. Plug into the same PCB connector.
• 7. Inspect PCB: If the sensor tests good but E1 persists, inspect the PCB for burnt tracks or corrosion around the sensor input. If damaged, the indoor PCB may need replacement.
• 8. Test operation: Reassemble the control box and front panel, restore power, and run the unit in cooling mode. Confirm that E1 does not reappear.

When to call a technician: If you are not comfortable using a multimeter or if the PCB appears damaged, contact an authorized Airwell service center.