1. Use the resistance gear of a multimeter to measure the resistance. A few ohms to tens of ohms is good, and thousands of ohms or even higher is bad.

2. According to the voltage and the design power of the heating tube, the resistance formula of the heating tube is calculated as R = (V x V) / P (R represents resistance, V represents voltage, P represents power). If the result is greater than 0 and less than 1000, it is good.

3. Therefore, use the ohm gear of the multimeter（ × 10 Ω) when measuring, if the reading is close to the large value or close to the large value, it is an open circuit. A reading indicates that it is normal without damage.

4. When the electric heating tube is not powered on, observe whether there are obvious holes, trachomas, cracks and tube bursts on the surface of the tube. If not, it is generally good. If the above imagination does not exist but can be used, then 1.2.3 methods can be used for testing.

Judgment method of heating pipe: if there are obvious holes, trachomas, cracks and tube bursts on the surface of the pipe body, it means that the heating pipe has been damaged and can no longer be used normally; When the measured resistance value is zero, it also indicates that the heating tube cannot be used; If the surface is intact and the resistance value is within the normal range, it is necessary to find other reasons.

Article source: heat pipe manufacturer http://www.gdtamman.com