Tips for Extending the Life of Band Heaters.
#1
Avoid Contamination
Both mica band heaters and ceramic band heaters are vulnerable to contamination. If sufficient moisture is present at start-up, the heater fails as soon as power is applied. Oil and other organics can cause heater failure if they get inside the metal sheath, but they behave differently than water.
#2
Avoid Over-Temperature
A loose fit of the band heater on its cylinder will reduce the heater’s lifetime because the heat generated is not transferred efficiently to the cylinder being heated, causing the heater to run at a higher temperature to transfer its energy. The higher the operating temperature, the shorter the lifetime.
#3
Excessive Cycling
With continuous cycling, the wire diameter is eventually reduced, and the resistance of the element is increased to the point that it becomes too hot. At that point, the element wire either melts and breaks open the circuit, or it causes the insulation over the wire to break down, causing a short to the sheath.
#4
Physical Abuse
Never carry a band heater by the lead wires. If the heater has post terminals, use two wrenches; one to hold the bottom nut and one to do the tightening on the top nut.