The HC error code in air conditioning systems is associated with faults in the electronic control board of the outdoor unit, specifically in the PFC module (Power Factor Correction) of the power supply. This document explains its operation and how to resolve the issue.
How the PFC Module Works
- Receiving Current: The outdoor electronic board receives alternating current (AC) from the power grid, such as 220 V. The PFC module gets this current through a rectifier bridge (diode bridge).
- Current Conversion: The diode bridge converts alternating current into direct current (DC).
- Improving Current Quality: After the diode bridge, the DC current passes into the PFC circuit, which includes an IGBT transistor, a reactor, and a special diode. An integrated circuit controls these components to enhance current quality by correcting the power factor.
- Supplying the Compressor: When the IGBT transistor is active, the PFC circuit supplies DC to the smart power circuit, which powers the compressor.
- Transistor Deactivation: When the IGBT deactivates, the current is momentarily supplied by the magnetic field stored in the reactor.
Steps to Resolve the HC Code
A. Basic Reset
- Turn off the unit and disconnect it from the power supply for several minutes.
- Turn the unit back on and check if the error disappears.
B. Voltage Check
- Use a multimeter to check the power grid voltage. If it is abnormal, use a voltage stabilizer.
- With the board powered, measure the voltage at the diode bridge’s output. If the input is 220 V AC, the output should be 300 V DC.
- If the voltage is incorrect: Check the diode bridge. Turn off the unit, wait for the capacitors to discharge, and use a multimeter to test the diodes. Replace any diodes that conduct in both directions or show abnormal readings.
C. Inspecting the PFC Circuit
- If the voltage after the diode bridge is correct, inspect the following in the PFC circuit:
- Visually check the capacitors and measure their capacitance.
- Check the reactor’s electrical continuity.
- Inspect the PFC circuit diode to ensure it conducts in only one direction.
D. Testing the IGBT Transistor and Its Driver
- IGBT Structure:
- It has three pins: collector, gate, and emitter.
- The IGBT activates with a minimum voltage of 5 V between the gate and emitter, allowing current flow between the collector and emitter.
- Basic Operation:
- When active, current flows from the collector to the emitter.
- The IGBT acts as an electronic switch, controlling current flow.
- Testing the IGBT:
- Use a multimeter to test the transistor’s pins.
- Replace the transistor if necessary.
- Checking the IGBT Driver:
- The driver provides the required voltage to the gate pin, activating and deactivating the transistor rapidly (up to 200,000 times per second).
- Verify that the driver receives and sends signals correctly.
