The maintenance of air duct heater mainly includes the following aspects:

Keep a safe distance. If the resistance wire continues to work after multiple maintenance, it will cause excessive load on the line, so in the machine work, flammable and explosive things can not be placed around the electric heater, and a certain safe distance should be maintained. It is best not to use cables that have been repaired many times, and to replace them in time.
Check regularly. For air duct heaters not used for a long time, the power supply should be cut off. In addition, the grounding detection of the air duct heater should be checked frequently to prevent the poor grounding wire of the instrument from causing electric shock. Before starting, a 500V gauge should be used to detect whether the ground insulation resistance of the electric heater power terminal is more than 20M megohm (greater than 1.0 megohm can be used). In addition, it is necessary to regularly maintain and check the air duct heater circuit to avoid leakage at the power connection, as well as electric shock and fire.
Pay attention to the cable condition. The wire must be plugged. Do not plug the wire directly into the power socket. Electric heater wire aging damage, to replace immediately. Electric water heaters without a fuse must not be used on the line.
If you encounter problems that cannot be solved during maintenance, contact professionals for help.