Daily cleaning: Use neutral detergent to wipe the inner lining of the box daily to avoid residual corrosive solvents; Clean the condenser fins monthly, using compressed air or a soft bristled brush to remove dust and ensure efficient heat dissipation.

Periodic inspection: Check the pressure of the refrigeration system every quarter, monitor the high and low pressure values through a pressure gauge, and replenish refrigerant in case of abnormalities; Calibrate temperature and humidity sensors every six months, using standard thermometers or dry well furnaces to compare at 0 ℃, 50 ℃, 100 ℃, and 30%, 60%, and 90% RH points. If the deviation exceeds ± 2%, replacement is required.

Key component maintenance: Check the insulation resistance of the heating tube annually, use a megohmmeter to test, and replace it if the resistance value is below 1M Ω; Perform multi-point control calibration on the air duct circulation system, and arrange 9 T-shaped thermocouples at standard temperature points such as -40 ℃ and 85 ℃ to ensure temperature uniformity deviation of ≤± 2 ℃.

Safety device testing: Manually test the leakage protector every month, inject 30mA current to verify that the action time is ≤ 0.1 seconds; Check the over temperature protection function every quarter and simulate over temperature conditions to confirm the reliability of the linkage between the temperature controller and circuit breaker.

Quick diagnosis of common faults

Slow or stagnant cooling: Priority should be given to checking whether the condenser has accumulated dust. If the surface temperature rises abnormally, it needs to be cleaned; If the refrigerant pressure is low, R404A refrigerant needs to be replenished and the leakage point needs to be sealed; If the opening of the expansion valve is abnormal, it is necessary to replace the same specification accessories.

Excessive heating rate: After power failure, measure the resistance of the heating tube with a multimeter. If the resistance value is 0 or infinite, it needs to be replaced; If the sensor malfunctions, replace the PT100 sensor and recalibrate it; When the temperature control parameters are disrupted, restore the factory settings and reset the heating curve.

Excessive temperature difference inside the box: Check if the circulating fan is running. If the motor is stuck, add high-temperature lubricating oil; Clean up debris in the air duct to ensure smooth airflow circulation; Avoid placing samples too densely and reserve sufficient air duct space.

Overtemperature alarm triggered incorrectly: After removing the sample, check if the thermostat is functioning properly. If the sensor error causes protection failure, repair is required; If the sample releases a large amount of heat, it is necessary to reduce the load or optimize the test plan.