What Are The Troubleshooting Measures for Abnormal Temperature Rise inside The Fume Hood?

If the temperature inside the fume hood abnormally rises, the following steps can be taken to handle the fault:

Inspect the ventilation system

Check the status of the air valve: If there is a sound of wind but no wind when the fume hood is opened, it might be that the air valve is not open. At this point, the power line of the air valve contact in the fume hood electrical control box can be tested to check whether the output voltage is normal when it is opened and closed. If the voltage is abnormal, the damper control circuit needs to be further investigated.

Clean the air inlet filter: A clogged air inlet filter will affect the ventilation effect and cause the temperature inside the fume hood to rise. The air inlet filter screen should be inspected and cleaned regularly to ensure smooth ventilation.

Check the cooling fan: Test whether the cooling fan is operating normally. If the speed is insufficient, it may be a fan failure or a power supply issue. The fan needs to be repaired or replaced, and the power supply line of the fan should be inspected.

Adjust the ventilation system: If the ventilation system is not designed reasonably, such as the diameter of the ventilation duct being too small or the ventilation path being unsmooth, it may also cause the temperature inside the fume hood to rise. At this point, it is advisable to consider adjusting the ventilation system, such as replacing ventilation ducts of appropriate diameters or optimizing ventilation paths, in order to lower the temperature.

Check the temperature control system

Check the temperature sensor: A malfunction of the temperature sensor may lead to inaccurate temperature monitoring and affect the temperature control of the fume hood. It is necessary to check whether the temperature sensor is working properly. If it is damaged, it should be replaced in time.

Adjust the parameters of the temperature controller: If the temperature controller of the fume hood is not adjusted properly, such as the temperature sensing tube being mistakenly placed at the inlet of the evaporator, the temperature inside the box will not drop to the required value when the temperature controller operates. The position of the temperature controller and the temperature sensing tube of the air curtain cabinet can be adjusted to ensure that the temperature controller can accurately control the temperature inside the fume hood.

Check environmental factors

Check the placement of the fume hood: If the ambient temperature around the fume hood is too high and the air circulation is poor, it will lead to low heat transfer efficiency and cause the temperature inside the fume hood to rise. The fume hood should be placed in a cool and well-ventilated area. When placing it, there should be a certain gap between it and surrounding objects to avoid direct sunlight and crowded surroundings.

Check the experimental operation: Excessive heat generated during the experiment may also cause the temperature inside the fume hood to rise. It is necessary to check whether the experimental operation is standardized, such as whether a large number of heat-generating devices have been used and whether high-temperature experiments have been conducted for a long time. If necessary, the experimental plan can be adjusted to reduce heat generation.

Check for internal faults in the equipment

Check the refrigeration system: If the refrigeration system of the fume hood leaks or gets blocked, the refrigeration efficiency will decrease, resulting in a higher temperature inside the fume hood. First, it should be determined whether it is a leakage or a blockage. If it is a leakage, the system pipeline should be checked for leaks and repaired. If clogged, the drying filter can be replaced. If necessary, nitrogen gas should also be blown into the pipeline to remove impurities.

Check the compressor: Internal faults in the fume hood compressor can reduce work efficiency and decrease the cooling capacity. At this point, the compressor casing should be cut open for repair, or professional maintenance personnel should be contacted for maintenance.