Daily maintenance of marine heat pump units must take into account the vessel’s unique environmental conditions (such as high salt spray, vibration, and space constraints) as well as the equipment’s operational characteristics. Particular attention should be paid to corrosion prevention, system stability, and maintaining energy efficiency. The following are the key maintenance points:

1. Regular cleaning and anti-corrosion treatment

Heat Exchanger Cleaning: Check the heat exchange efficiency of the evaporator and condenser weekly. If scaling, salt spray buildup, or dust accumulation is observed, clean these components using a soft-bristle brush or a specialized cleaning agent (such as a mild acidic descaling solution). For condensers cooled by seawater, flush the piping with fresh water monthly to prevent marine organisms from attaching and salt crystals from forming.

Filter Maintenance: Clean the air filter daily (especially in the cabin and cockpit areas) to prevent dust buildup that could reduce airflow. If the filter material is metal, apply a rust-preventative coating regularly to protect against corrosion from salt spray.

Corrosion Prevention for Metal Components: Inspect weekly the unit’s enclosure, pipe connections, valves, and other metal components. If any coating is damaged, promptly touch up with anti-corrosion paint. Electrical terminal blocks should be treated with a moisture-resistant insulating spray to prevent short circuits caused by moisture.

2. System Operating Parameter Monitoring

Pressure and Temperature Checks: Daily record the compressor suction and discharge pressures, condensing temperature, and evaporating temperature to ensure they remain within the equipment’s specified ranges. (For example, excessively high condensing pressure may indicate a dirty or blocked condenser, while excessively low suction pressure could suggest a refrigerant leak.)

Current and Voltage Monitoring: Regularly check the operating current of motors such as compressors and fans, as well as the supply voltage, to prevent overloading caused by fluctuations in the ship’s electrical grid (a voltage regulator can be configured for additional protection).

Refrigerant Leak Detection: Use a leak detector weekly to check for leaks at vulnerable points such as pipe connections and valves. If a leak is detected, immediately stop the system for repair and replenish the refrigerant with the same model according to regulations (the refrigerant must meet IMO environmental requirements; the use of high-GWP refrigerants is prohibited).

3. Maintenance of Key Components

Compressor Maintenance: Check the compressor lubricant oil level and color monthly. If the oil level is insufficient, top up with lubricant of the same model. If the oil turns black or becomes emulsified (possibly due to water ingress), completely replace the lubricant and inspect for sealing issues.

Fan and Pump Inspection: Weekly inspections should be conducted to check whether the fan impeller and pump impeller are loose due to vibration, and whether any foreign objects have adhered to the blades. The bearing areas must be lubricated quarterly with high-temperature-resistant and corrosion-resistant grease to prevent damage caused by overheating due to friction.

Valve and Piping Maintenance: Manually operate all shut-off valves and throttling valves monthly to prevent them from becoming stuck due to prolonged inactivity. Flexible piping (such as rubber hoses) should be inspected for signs of aging or cracking, especially in areas subject to severe vibration; if necessary, replace these with materials that offer enhanced weather resistance.

4. Inspection of Control Systems and Safety Devices

Sensor Calibration: Calibrate temperature and pressure sensors quarterly to ensure data accuracy. (For example, excessive deviation in temperature sensors can cause the unit to frequently start and stop.)

Safety Protection Testing: Regularly test devices such as overload protection, high-pressure protection, and freeze protection. Simulate fault conditions (e.g., artificially increasing condensing pressure) to verify that the equipment can automatically shut down and trigger an alarm.

Control panel cleaning: Wipe the control panel with a dry, soft cloth to prevent salt spray or moisture from entering. Check whether the buttons and display screen respond properly to ensure that poor contact does not cause operational failures.

5. Maintenance for Special Environmental Adaptability

Vibration Prevention Measures: Inspect weekly whether the unit’s mounting bolts and vibration-damping pads are loose. If any abnormal vibrations are detected, make timely adjustments to prevent pipe connections from fracturing due to long-term vibration fatigue.

Response to Extreme Weather: Before encountering adverse sea conditions, reinforce the external protection of the unit and close the fresh-air valves to prevent seawater from flowing back into the system. During low-temperature navigation, if the unit is temporarily out of service, drain all water from the pipelines—especially those in the freshwater system—to avoid freezing and subsequent pipe rupture.

Spare Parts Management: Stock up on wear-and-tear parts (such as filters, seals, and fuses), and ensure they are stored in a moisture-proof and corrosion-resistant environment to guarantee quick replacement in emergencies.

6. Recording and Fault Tracking

Establish a maintenance logbook to record data from each inspection, fault symptoms, and corresponding corrective measures, facilitating analysis of equipment operating trends. For example: If high condensing pressure occurs frequently, it may be necessary to thoroughly clean the condenser or check the flow rate of the seawater pump; if heating efficiency declines, it’s essential to inspect whether the heat pump reversing valve is stuck or malfunctioning.

Through the above maintenance measures, the service life of marine heat pump units can be effectively extended, unexpected failures during navigation can be reduced, and stable operation in complex environments—such as those characterized by high salinity, vibration, and fluctuating loads—can be ensured.