I. Daily Maintenance and Precautions
To improve the service life of ultra-low temperature freezers, maintain good operating conditions, and reduce the failure rate, daily maintenance and upkeep are essential.
(1) Ambient Temperature. The operating environment temperature of the ultra-low temperature freezer must be below 32℃, with good ventilation. Poor ventilation or excessively high temperatures can easily cause the equipment to overload and be damaged. If necessary, a high-powered air conditioner should be installed in the room where the ultra-low temperature freezer is located to ensure a good temperature environment.
(2) Refrigerator Door Seal. If the door seal is aged and the door is not sealed tightly, the cooling effect will be severely reduced, causing the compressor to operate under overload for a long time and be damaged. For aged door seals, replace them promptly to ensure that the refrigerator door can be closed tightly.
(3) Defrost Removal. Ultra-low temperature refrigerators are particularly prone to frost and ice buildup, especially in humid southern regions. Therefore, defrosting of the door panels, door seals, and inner doors of each shelf should be done promptly. It is strongly recommended to defrost immediately after each sample storage or retrieval!
(4) Cleaning. Use a dry cloth to remove dust from the inside and outside of the refrigerator and its accessories. If the refrigerator is very dirty, clean it first with a neutral detergent, then rinse thoroughly with purified water. However, be sure not to rinse the inside and top of the refrigerator directly with water, as this will damage the insulation and cause malfunctions.
(5) Safety Inspection. Ensure three things are done: 1. The refrigerator plug is properly inserted without any loose connections; 2. The plug is not abnormally hot; 3. The refrigerator's distribution and power cables are free of scratches and cracks.
II. Possible Problems and Suggestions
Problem 1: The leakage circuit breaker trips after the ultra-low temperature refrigerator is connected to the power supply, and the equipment cannot be used normally. Recommendation 1: This situation is mostly caused by short circuits or leakage from burnt-out electrical equipment. Generally, use an insulation resistance meter or a multimeter set to 10 kΩ or higher to test the insulation resistance of the electrical system; it should not be less than 2 MΩ. Disconnect the compressor, controller, cooling fan, starting capacitor, relays, etc., to test the insulation of the circuit.
Problem 2: The ultra-low temperature freezer has a normal temperature, but is extremely noisy.
Recommendation: For ultra-low temperature freezers experiencing excessive noise, check the stability of the freezer and the effectiveness of the compressor's vibration damping. The compressor vibrates during operation, and uneven placement or poor vibration damping will cause noise. If the noise is caused by uneven placement, adjust the height of the freezer's feet to ensure stability.