How to deal with the problem of frosting on the surface of the evaporator in the constant temperature and humidity test chamber

Frost formation on the surface of the evaporator in a constant temperature and humidity test chamber is usually caused by improper temperature and humidity parameter settings, decreased equipment sealing, or refrigeration system failures. Targeted measures should be taken based on specific reasons. ‌

Temporary handling and safe operation: After discovering frost, pause the experiment first and transfer the samples inside the box to a safe environment to avoid the influence of temperature and humidity fluctuations; Subsequently, turn off the device power, open the box door to allow the frost layer to melt naturally, and strictly prohibit using sharp tools to scrape or damage the refrigeration pipeline. After melting, wipe the internal moisture with a dry soft cloth, especially paying attention to the door seal and corner water accumulation; Before restarting, ensure that the interior is dry. If frost quickly recurs, record the location of the frost and contact after-sales. ‌

Parameter adjustment and daily maintenance: Check the temperature and humidity settings. If the temperature is too low (below the ambient dew point temperature) or the humidity is too high, increase the temperature inside the box or decrease the humidity setting value appropriately to reduce water vapor condensation; At the same time, regularly clean the dust and stains on the surface of the evaporator, maintain smooth ventilation, avoid air duct blockage, and check the sealing of the door seal every week. Replace aged or deformed door seals in a timely manner to reduce the infiltration of humid air from the outside. ‌

Refrigeration system inspection and maintenance: If frosting occurs frequently and parameter adjustments are ineffective, it is necessary to investigate the refrigeration system problems, such as insufficient or excessive refrigerant, or improper adjustment of the expansion valve, which may cause the evaporator surface temperature to be too low; In addition, ventilation fan failure or defrosting device failure (such as sensor damage) can also cause frosting, requiring personnel to detect pressure, repair leaks, or replace faulty components. ‌

Preventive measures: Keep the box dry when not in use for a long time, place silica gel desiccant and replace it regularly; Before conducting low-temperature testing, ensure that the dehumidification system is operating normally to avoid rapid cooling or excessive opening of doors; Regularly maintain key components such as compressors and heat exchangers by personnel to ensure system operation. ‌