Fault Phenomenon: Sumitomo crawler crane cab AC vents do not blow cold air, compressor cycles on and off frequently.

Troubleshooting Process:
– Checked condenser: clogged with mud.
– Checked refrigerant pressure: high pressure too high, low pressure too low.
– Cleaned condenser, recharged refrigerant.

Root Cause: Poor condenser heat dissipation caused system high-pressure protection, causing the compressor to cycle frequently.

Required Parts: Refrigerant, cleaner.