Dehumidifier Safety Fact Sheet Recent Dehumidifier Fires Dehumidifiers are a convenient and cost-effective means of improving home indoor air quality by removing moisture from the air. However, improper use, poor maintenance, manufacturing defects, and design defects can cause failure and overheating and fires. In recent years, dehumidifiers have been plagued by numerous recalls due to defects and failures which have become increasingly apparent in our own forensic investigations. Dehumidifier Recalls For information on recalled dehumidifiers visit: https://www.cpsc.gov/Recalls and search “dehumidifier.” Dehumidifier Failures - Operation and Maintenance A user should follow reasonable operating and maintenance instructions as provided by the manufacturer to ensure effective, reliable and safe operation to prevent failures, which can cause overheating and fire. Dehumidifier Location Most manufacturers recommend a minimum clearance of 8-12 inches around the dehumidifier. Airflow must not be restricted through the cabinet louvers on the front, back and sides. Restricted airflow can cause compressor or fan overheating. Dehumidifiers must be operated in an enclosed area with the outside doors and windows closed. Little outside air should be allowed to enter the room. Running a dehumidifier in endless humid conditions can cause the unit to run nonstop and cause compressor overheating. Room Temperature Most dehumidifiers are designed to work at a room temperature of 65°F or above. Temperatures below 65°F can cause the coil to get too cold and freeze up. A frozen coil can cause compressor overheating. New “low temp” models are now available which allow operation down to 40°F. Humidistat Setting The humidistat on the dehumidifier sets the desired humidity level in the air. Setting it too low can cause the unit to run nonstop, potentially overheating the compressor. Cleaning the Air Intake and Exhaust Grills Dehumidifier air intake and exhaust grills must be periodically cleaned with a vacuum cleaner to ensure proper airflow through the cabinet. Undue stress on the fan can cause it to overheat and fail. Restricted airflow can also cause compressor overheating. Filter Replacement Air intake filters must be replaced as needed to ensure proper airflow through the cabinet. Undue stress on the fan can cause it to overheat and fail. Restricted airflow can also cause compressor overheating. Cleaning the Coils The dehumidifier condenser (reheat) coil must be periodically cleaned with a vacuum cleaner. Over time the air can cause a thick buildup of dust and dirt on the coils. Undue stress on the fan can cause it to overheat and fail. Restricted airflow can also cause compressor overheating. The dehumidifier evaporator (cooling) coil must also be periodically cleaned with a vacuum cleaner. Over time the air can cause a thick buildup of dust and dirt on the coils. This buildup may cause water to freeze on the coils. A frozen coil can cause compressor overheating. Dehumidifier Components and Common Failure Modes Fan The fan pulls room air into dehumidifier and pushes dry air out into room Compressor The compressor is a motor-driven device that compresses and expands a refrigerant gas like freon to cool the dehumidifier’s cooling coil. A compressor serves as the heart of the system. Although heat is a normal consequence of compression, a system that gets too hot will overheat. Overheating is one of the most common causes of compressor failure. Excessive overheating is controlled and prevented by a compressor thermal protector. .