1. The reversing valve of concrete mixer can not change direction or the reversing action is slow, which is generally caused by poor lubrication, spring stuck or damaged, oil or impurities stuck sliding part and other reasons. At this time, we should first check whether the oil atomizer works normally and whether the viscosity of the lubricating oil is appropriate. If necessary, replace the lubricating oil, clean the sliding part of the directional valve, or replace the spring and directional valve.
2. After being used for a long time, the reversing valve of mixer truck is prone to wear of valve core sealing ring, damage of valve stem and valve seat, resulting in gas leakage in the valve, slow action or abnormal reversing of the valve. At this time, the sealing ring, valve stem and valve seat need to be replaced, or the change-over valve needs to be renewed.
3. If the inlet and exhaust holes of the solenoid pilot valve are blocked by oil sludge or other debris, the sealing is not tight, the movable iron core is stuck, and the circuit is faulty, the reversing valve can not be normally reversed. For the first three cases, the oil sludge and impurities on the pilot valve and movable iron core should be cleaned, and the circuit faults can be divided into circuit faults and solenoid coil faults.
Before checking the circuit fault, turn the manual knob of the directional valve a few times to see whether the directional valve can change direction normally under the rated air pressure. If it can change direction normally, the circuit is faulty. When checking, use the instrument to measure the voltage of the solenoid coil to see whether it reaches the rated voltage. If the voltage is too low, further check the power supply and related lines in the control circuit The circuit of the range switch. If the reversing valve can not change direction normally under the rated voltage, check whether the connector of the solenoid coil is loose or not. Check method: pull off the plug and measure the resistance of the coil (generally between several hundred ohm and several thousand Ohm). If the resistance is too large or too small, it means that the solenoid coil is damaged and needs to be replaced.