1. Check the power supply circuit of the good price and quality 4 way reversing valve. The air conditioner only supplies power to the good price and quality 4 way reversing valve during heating operation. Through the power supply inspection, it can be determined whether the problem is the good price and quality 4 way reversing valve or the problem. Control circuit problem.

2. Check the coil of the good price and quality 4 way reversing valve. After confirming that the power supply is normal, you should check whether the coil is normal. When the coil is energized, you should be able to hear the "click" sound generated when the iron core is pulled in. The sound of "呲呲" produced by the reversal of the main valve. When it is suspected that there is a problem with the coil, its resistance can be measured. Normally, it should be around 1.4KΩ. If the resistance value is small or infinite, it indicates that there is a short circuit or an open circuit inside the coil. When the coil is disconnected, the cooling is normal, but the heating cannot be performed, and the evaporator of the internal unit is frosted. When the coil is short-circuited and the machine heats up, it may burn out the fuse and make the whole machine unable to work.