ActronAir Gas Valve (Large) controls refrigerant gas flow in WRC series wall split outdoor units requiring the larger valve format on compatible ActronAir R22/R410A split ducted and wall split systems. Confirm valve specification from system service documentation -- small (WRC2617A) and large (WRC3517A) variants exist for different WRC models. Isolate power and recover all refrigerant before replacing any refrigerant circuit valve components.