The air conditioning system of an excavator works on a similar principle to that of an automobile, consisting of a compressor, condenser, evaporator, expansion valve/capillary tube, blower, pipelines, and control circuits. Due to dusty environments, strong vibrations, and poor heat dissipation conditions, air conditioning failures are quite common in excavators. Below is a summary of common failures and repair methods:

1. Poor Cooling or No Cooling

• Possible Causes

  • Insufficient or leaking refrigerant (Freon)

  • Compressor damaged or low efficiency

  • Poor condenser heat dissipation (dust buildup, fan failure)

  • Evaporator icing or blockage

  • Expansion valve malfunction

• Repair Methods

  • Check with pressure gauges; recharge refrigerant if low

  • Inspect pipelines, joints, condenser for leaks → repair, vacuum, and recharge

  • Clean condenser and evaporator dust buildup

  • Replace faulty compressor or valve components

2. Weak or Low Airflow

• Possible Causes

  • Blower motor failure

  • Air ducts blocked by dust, leaves, or debris

  • Cabin air filter clogged

• Repair Methods

  • Inspect blower motor, repair or replace

  • Clean air ducts and evaporator fins

  • Replace cabin air filter

3. Abnormal Noise

• Possible Causes

  • Compressor internal damage (seizure, bearing wear)

  • Blower wheel imbalance or foreign objects

  • Vibration from loose pipelines

• Repair Methods

  • Inspect compressor, replace if necessary

  • Remove debris, repair blower

  • Secure pipelines and brackets

4. Frost on Pipelines but No Cooling

• Possible Causes

  • Expansion valve improper opening or blockage

  • Excessive or insufficient refrigerant

  • Insufficient evaporator airflow

• Repair Methods

  • Inspect and adjust expansion valve

  • Refill refrigerant to specified amount

  • Clean air ducts and filters

5. AC Not Operating (Completely Shut Down)

• Possible Causes

  • Blown fuse

  • Control panel/switch malfunction

  • Compressor electromagnetic clutch failure

  • Pressure switch protection (high or low pressure abnormal)

• Repair Methods

  • Check electrical system → replace fuse, repair wiring

  • Test control panel and switches → replace faulty components

  • Inspect clutch coil and power supply

  • Measure system pressure → troubleshoot leaks or blockages

Maintenance and Prevention

1. Regularly clean condenser and evaporator (recommended every 500+ hours of operation).

2. Check and replace cabin air filter to ensure airflow.

3. Regularly monitor refrigerant pressure, recharge when insufficient.

4. Avoid running AC for long periods at idle speed to reduce compressor load.

5. Check system sealing every spring, prevent refrigerant leakage.