Error Code: EC 56 – Indoor Coil Outlet Temperature Sensor (T2B) Error (Multi-Zone)

Error Code: EC 56 – Indoor Coil Outlet Temperature Sensor (T2B) Error (Multi-Zone)
Applies to LETO and AURA Series

What this means:
The system has detected that the T2B sensor, which monitors the coil outlet temperature in multi-zone units, is either disconnected, shorted, or reading abnormally. This can cause the system to shut down to prevent improper operation.

Try this first (easy fix):

1. Turn off power to your mini split completely.

2. Wait 2 full minutes.

3. Turn the power back on and check the display.

• If the error is gone — the system is back to normal.

• If the error stays — proceed to the next steps.

Next steps (for technicians):

• Check the connection between the T2B sensor and the outdoor PCB.

• Make sure the wiring is secure and not damaged.

• Measure the resistance of the sensor:

  • If resistance is outside the acceptable range, replace the sensor.

  • If the sensor is fine, but the error persists, the outdoor PCB may be at fault.

What you might need:

• T2B sensor (indoor coil outlet sensor – used in multi-zone systems)

• Outdoor PCB

• Connection wires

Helpful tip:
T2B is only used in multi-zone configurations. If your system is a single-zone unit, this sensor and error code typically don’t apply. This error is triggered when the voltage drops below 0.06V or rises above 4.94V.

Click here to view the detailed guide.TS05-ODU