A failing TXV rarely throws a fault code — it shows up as frost on the suction line, erratic superheat, or a system that won't hold temperature no matter how much refrigerant gets added. This guide walks through the five field symptoms that point to the valve (not the charge), how to confirm a bad TXV before replacing it, and how to match the right replacement by refrigerant type and equalization style — with notes on the Danfoss 068U1839, Copeland Alco 091050, and Amana-Goodman OEM valves.
