A: The line heater is the main power line magnetic switch and then sucked through a heating pipe, it should be the first detection of a magnetic switch suck the contacts are normal. The line does not pass the one phase, the above phenomenon occurs. The pipette magnetic switch is normal, the meter can then check to see if each of the ohmic value of the phase of the machine is the same. If the normal should be short-circuited. If all phases are turned on but still abnormal lines or electric tube, replace the heater.