The driving and pumping conversion of the concrete boom pump truck generally uses a two-position five-way electromagnetic reversing valve. There is a pressure regulating valve for regulating air pressure in the middle of port 1 leading to the chassis air tank. When the circuit is connected to the coils at both ends of the solenoid valve, the valve core is forced to realize the non-stop connection of the air circuit, so that the transfer case cylinder performs the piston movement.

In addition, the reason for the lack of pressure difference is that the air inlet connection of a and b is poorly sealed, and there is a sound of air leakage at the air connection. In such a situation, you can unplug the air pipe and check whether the air leak is caused by dust, otherwise, you can replace a new air pipe or joint.

Troubleshooting: If it is a failure of the air valve and there is no replaceable air valve on site, the air intake pipe can be directly connected to the port 2 and 4 of the transfer case cylinder through the joint. If the piston is worn, hydraulic oil can be used to coat the piston, which can provide a temporary emergency effect.

Under normal circumstances, the valve or the problem that occurs is that the coils at both ends of the solenoid valve cannot be energized, or there will be a power failure or short-circuit phenomenon that can not operate normally. Occasionally, the valve core will become stuck, causing the air path to be unsmooth.

Troubleshooting: If there is no problem with the gas circuit and the valve core, then manually press the buttons at both ends of the solenoid valve to switch normally, then the circuit and coil problems must be detected. If the DC voltage of the multimeter is used to detect that the voltage of the coil connector is normal, it should be a problem of coil failure. At this time, you can directly measure the resistance of the coil or replace it with a new coil to work normally.