The four-way valve is in the refrigeration plant the essential part, its principle of work is, when the solenoid valve coil is at the power-off condition, like chart , the forerunner slide-valve shifts to the left under the right flank compression spring actuation, the compressed gas enters the capillary vessel

Right margin latter enters the piston cavity, on the other hand, left side the piston cavity's gas discharges, as a result of the piston both sides existence differential pressure, the piston and the main slide valve shifts to the left, causes the exhaust pipe to be interlinked with the outdoor machine control, another two controls are interlinked, form the refrigeration cycle. when the solenoid valve coil is at the circular telegram condition, the forerunner slide-valve in the magnet coil produces under the magnetic force function overcomes compression spring's tensity, but the right lateral, the compressed gas enters the capillary vessel

Left side latter enters the piston cavity, on the other hand, right margin the piston cavity's gas discharges, as a result of the piston both sides existence differential pressure, the piston and the main slide valve right lateral, causes the exhaust pipe to be interlinked with the indoor machine control, another two controls are interlinked, form the system to circulate hotly