Error Code: EC 52 – Outdoor Coil Temperature Sensor (T3) Error

Error Code: EC 52 – Outdoor Coil Temperature Sensor (T3) Error

What this means:
The outdoor coil sensor (T3) is reporting a fault due to an open circuit, short circuit, or voltage reading outside the normal range. When the sensor’s sampling voltage falls below 0.06V or rises above 4.94V, the system triggers EC 52 and shuts down to prevent incorrect operation.

Try this first (quick reset):

1. Turn off the 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 issue may have been temporary.

• If the error remains — proceed to the diagnostic steps.

Next steps (for technicians):

1. Check sensor wiring to the PCB:

   • Confirm the T3 sensor is properly connected and undamaged.

   • If not → repair or replace the connection wires.

2. Measure resistance of the T3 sensor:

   • If the resistance is not within normal range → replace the T3 sensor.

   • If it is within range but error persists → replace the outdoor PCB.

What you might need:

• T3 (coil) temperature sensor

• Outdoor PCB

• Connection wires

Helpful tip:
This error is part of the broader EC 50-series sensor protections. If your unit uses a combination sensor for T3, T4, and TP, replacing one may require replacing the entire sensor assembly.

Click here to view the detailed guide.TS18