How To Verify High Quality Cartridge Heaters

 The most intuitive way to verify the quality of cartridge heater

First,clean the surface of heater pipe,then connect it to 220volt power,heating in the air,cut off the electricity when the surface turns to red.When the heater completely cool,wipe with a napkin.If there’s no black oxide power(didn’t react with oxygen in the air),described that the heater is with high quality.