Service manual

AUX air conditioner service manual
26
②one-way Valve
Check valve is also called anti-reverse valve. it permits the refrigerant to flow in only one direction in
the refrigeration system, and to be installed in the pipes for preventing process flow from
reversing. It is mainly applied in the heat pump air-conditioner and adopted as the assistant to the
electromagnetic reversing valve for changing the refrigerant’s flow direction and the system’s pressure.
Generally, there is an arrow marked on the outer surface of the one-way valve for indicating the flow
direction of the refrigerant.
The one-way valve is divided into the spherical valve and the needle valve. They are in the simple
structure. For example in the below picture, when the refrigerant flows in the direction as the arrow
indicates and when the pressure at A side is higher than the one at B side, then the steel ball (or valve
needle) moves to the left side, and the refrigerant flows from A to B, the one-way valve opens.
However, when the refrigerant flows in a reverse direction and when the pressure at B side is higher
than the one at A side, then the steel ball (or valve needle) moves to the right side, which jams the
refrigerant’s flow route, and the one-way valve is in close status.