The MK-4601 features an 11 square inch diaphragm

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

making it the standard choice for professional contractors maintaining W18AF

Zero Differential Operation: The piloted diaphragm design allows the valve to open and close reliably without requiring a minimum pressure drop

Its compact footprint and 24V furnace gas valve configuration make it the professional’s choice for restoring factory-spec safety and throughput in residential furnaces and light commercial air handlers

Carrier 340620-720 TXV Kit Replacement 318973-401 The MK-4601 features an 11The 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