Danfoss 068U3731 TUB Thermostatic Expansion Valve TXV for R290, 1/4 x 1/2 in Solder

The Danfoss 068U3731 is a TUB-series thermostatic expansion valve (TXV) for R290 (propane) refrigeration systems. It meters liquid refrigerant into the evaporator by sensing refrigerant superheat. This keeps evaporator performance stable and helps protect the compressor from liquid refrigerant.

Key Features:

• Refrigerant: R290, approved by ignition source assessment under EN 13463
• Body material: Stainless steel with a laser-welded power element for structural integrity and long life
• Configuration: Angleway, single-flow, with a laser-engraved flow direction arrow
• Connections: 1/4 in inlet x 1/2 in outlet, solder (ODF)
• Pressure equalization: Internally equalized
• Orifice: Size 1, fixed, with a nominal capacity of 0.94 kW (about 0.27 TR)
• Temperature range: -40 to 10 °C (-40 to 50 °F), without MOP
• Static superheat: 4 °C (7.2 °F), adjustable superheat setting
• Capillary tube: 31 in (800 mm), flexible and vibration-resistant
• Maximum working pressure: 34 bar (500 psig)
• Approvals: EAC, LLC CDC, TYSK, UL
• Included: Bulb strap
• Serviceable: No (hermetic, non-replaceable power element)

This compact, lightweight valve suits commercial refrigeration, cooling equipment, liquid coolers, ice machines, heat pump systems and other R290 applications. Always follow the manufacturer's instructions for bulb placement and superheat setup.