Error Code: EC 5B – Failure of Enthalpy Outlet Temperature Sensor

Error Code: EC 5B – Failure of Enthalpy Outlet Temperature Sensor

What this means:
The enthalpy outlet temperature sensor is either open-circuited, short-circuited, or returning a voltage outside the safe range. If its sampling voltage falls below 0.06V or rises above 4.94V, the system triggers EC 5B and shuts down to avoid operating with invalid sensor data.

Try this first (quick reset):

1. Turn off power to the unit completely.

2. Wait 2 full minutes.

3. Turn the unit back on and check if the error clears.

• If the error clears — the fault may have been temporary.

• If the error remains — proceed with the steps below.

Next steps (for technicians):

1. Check the sensor wiring:

   • Ensure the enthalpy outlet sensor is securely connected to the PCB.

   • Repair or replace any damaged or loose wires.

2. Measure the sensor resistance:

   • If resistance is out of range → replace the sensor.

   • If resistance is within spec but error persists → replace the PCB.

What you might need:

• Enthalpy outlet temperature sensor

• Indoor PCB

• Connection wires

Helpful tip:
Sensor faults like EC 5B are usually resolved with simple wire or sensor replacement. If multiple enthalpy sensors are failing together, the PCB may be the root cause.

Click here to view the detailed guide.TS18