Pre-operation Preparation
Shutdown duration requirement: If the equipment has been idle for an extended period, ensure it has been shut down for at least 48 hours before startup to prevent malfunctions caused by unresolved internal pressure or oil sedimentation.
Power supply check: Before engaging the main power switch, verify that the voltage and frequency match the equipment nameplate specifications and ensure a reliable ground connection to prevent compressor damage from electrical leakage or voltage instability.
Refrigeration oil preheating: After powering on, preheat the oil for at least 24 hours to bring its temperature into the operating range (typically 40–60°C); this ensures proper lubrication and minimizes compressor wear.
Startup Procedure
Valve operation sequence: Slowly open the compressor discharge valve and the liquid line three-way valve. Rapid opening can cause sudden system pressure fluctuations, leading to pipeline vibration or seal damage.
Oil level check: Observe the lubricating oil level via the sight glass; it must remain between the upper and lower limit marks. An excessively low level results in insufficient lubrication, while an excessively high level may allow oil to enter the refrigeration system, impairing heat exchange efficiency.
Refrigerant mode confirmation: Configure the refrigerant mode (e.g., R22, R410A) in advance based on ambient temperature and equipment requirements to ensure system compatibility and prevent refrigerant leakage or performance degradation.
Operational Monitoring
Scheduled Inspections: Once the unit is running, the operator should conduct inspections every two hours and record operating data (such as temperature, pressure, and current) to facilitate the early detection of anomalies.
Vibration and Noise Checks: If the unit exhibits abnormal vibration or noise-potentially caused by unstable installation, loose components, or compressor failure-it must be shut down immediately for troubleshooting.
Control Cabinet Inspection: Observe the components inside the control cabinet (e.g., contactors, relays) to ensure they operate smoothly and check for signs of scorching or unusual odors to prevent electrical fires.
Piping and Insulation Checks: Inspect refrigerant piping connections for tightness and ensure the insulation layer is intact; this prevents cooling loss and avoids equipment short circuits caused by dripping condensation.
Pressure Gauge Verification: After the compressor starts, verify that the high-pressure gauge (condensing pressure) and low-pressure gauge (evaporating pressure) readings are within normal ranges (e.g., high pressure: 1.5–2.5 MPa; low pressure: 0.4–0.6 MPa). Abnormal readings may indicate insufficient refrigerant, a clogged filter, or fan failure.
Cold Air Outlet Inspection: Confirm that airflow is uniform and temperatures meet specifications at all cold air outlets. If airflow is weak or cold air is absent in a specific area, the cause may be a blocked air duct or fan failure.
