For this specific Trane blower assembly

California Proposition 65 compliant for professional environmental standards

loosen the seal nut and turn the adjusting stem clockwise to increase the pressure or counter-clockwise to decrease it

this specific expansion valve kit is engineered strictly for R-410A pressure and temperature curves

making it the standard choice for professional contractors maintaining W18AF

Carrier 340620-720 TXV Kit Replacement 318973-401 For this specific Trane blowerThe Carrier 340620 720 TXV Kit is a genuine OEM thermal expansion valve engineered for precise refrigerant metering in high performance HVAC systems. This Carrier TXV replacement part is the direct logistical successor to the 340620 755, ensuring a drop in fit for technicians servicing Carrier DU50HFA units and specific NRTP series evaporator coils. Unlike generic alternatives, this HVAC refrigerant valve maintains the exact superheat settings