The H3 error is a common code displayed on Mini Split air conditioners from various manufacturers. This code indicates an issue related to the compressor overload protection, which is typically triggered when the compressor temperature exceeds 115 °C (239 °F).
Possible Causes of the H3 Error Code
- High current in the compressor:
- Short circuit in the compressor.
- Faulty wiring.
- Issues with the electronic control board.
- Low voltage from the external power supply.
- Excessive compressor temperature:
- Overcharged refrigerant.
- Blockage in the capillary tube or expansion valve.
- Dirty condenser unit.
- Fan speed issues in the outdoor unit.
- False alarms:
- Loose wiring.
- Defective internal thermostat (inside the compressor) responsible for shutting off the system when it exceeds 115 °C.
How to Fix the H3 Error in Air Conditioners
The solution depends on the specific cause of the error. Follow these steps for troubleshooting:
1. Check the power supply voltage
- Ensure the external power supply is providing the correct voltage.
- Use a clamp meter to measure the equipment’s current consumption and rule out electrical overload.
2. Inspect the outdoor unit
- Check for normal fan operation.
- Ensure the condenser unit is clean and free of obstructions.
3. Examine the compressor thermostat
- Verify that the thermostat cable is properly connected.
- Inspect all electrical connections inside the condenser unit.
- Thermostat tests:
- Use a multimeter on continuity mode to confirm the thermostat is closed (allowing current to flow).
- Disconnect the thermostat and measure its resistance using the multimeter in ohm mode. Values between 1 and 500 ohms indicate the thermostat is functioning correctly.
- Resistances higher than 1 kilo-ohm indicate a defective thermostat that needs replacement.
- Test the thermostat outside the compressor by increasing the ambient temperature to ensure it activates when it exceeds 115 °C. If it does not shut off, the thermostat is faulty.
4. Inspect the capillary tube or expansion valve
- If these components are blocked, they may become excessively cold, sometimes forming ice on the outside.
5. Check refrigerant levels
- Excess refrigerant: Can lead to excessive current consumption, triggering the H3 error.
- Low refrigerant levels: In some cases, may cause abnormal gas temperatures in the compressor discharge, leading to the code.
- Use pressure gauges to measure the system pressure while the unit is running.
- Normal pressure: Approximately 120 PSI for systems using R410A or R32 refrigerants.
- High pressure: Indicates overcharged refrigerant.
- Low pressure: Indicates insufficient refrigerant.
