Thermo King 668121 Expansion Valve

The Thermo King 668121 expansion valve is a precision-engineered metering device designed for bus transport refrigeration systems. It controls the flow of refrigerant into the evaporator coil based on superheat feedback, ensuring efficient cooling capacity across varying load conditions. The valve features a stainless steel power element and brass body construction for corrosion resistance in harsh road environments. Compatible with Thermo King refrigeration units utilizing R-404A or R-452A refrigerants. Direct replacement for OEM part numbers 66-8121 and 668121. Cross-references include HFES 6-MC series valves. Installation requires standard refrigeration service procedures including evacuation and recharge.