One way valve is also known as the check valve, it is in the air conditioning system, often with the electronic expansion valve (capillary) in parallel, to control the positive and negative flow of refrigerant, so that the refrigerant can only flow in a certain direction.

The one-way valve is composed of a nylon valve needle, a valve seat, a limit ring and a casing. Generally, the outer surface of the one-way valve is marked with an arrow.

As shown below, the one-way valve allows the refrigerant to flow only in one direction, such as cold media flow in the opposite direction of the arrow, the valve body and the valve seat surface will be closed to close the loop, so that the flow of refrigerant stopped.

One way valve is generally used in the next up, the vertical installation, one-way valves are mostly used for heat pump air conditioner, and the use of electronic expansion valve or capillary parallel.