Error 191 — No temperature changes in EVA OUT during pipe inspection or wrong address

What does 191 mean?

During a pipe inspection or system check, the EVA OUT (evaporator outlet) temperature sensor shows no change, or the indoor unit has an incorrect address. This indicates a problem with temperature sensing or unit identification.

• Faulty EVA OUT sensor
• Lack of refrigerant flow affecting temperature readings
• Indoor unit configured with a wrong or duplicate address
• Communication problem with the sensor

Click steps to track your progress.

1. 1

   Confirm that the indoor unit has the correct and unique address assigned.

2. 2

   Verify the EVA OUT sensor is securely attached to the pipe and its wiring is intact.

3. 3

   Check for proper refrigerant flow through the evaporator coil (requires professional assessment).

4. 4

   Perform a power cycle of the indoor unit and the outdoor unit.

5. 5

   If the issue continues, contact a qualified technician to inspect the sensor or refrigerant system.