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The Robertshaw® FP-45 Antifreeze Valve uses a reliable, self-contained power element that is sensitive to temperature and operates without electrical power or sensors. In solar applications, the gate of the valve typically opens as temperatures decrease, allowing the liquid to spill and to be replaced by warmer water when the water is near the freezing point in solar panels. When warmer water enters, the gate of the valve is closed and the removal of water is interrupted.

  • Protect solar collectors and exposed piping from freezing
  • Easily installed on existing systems
  • 125 P.S.I. maximum operating pressure
  • Corrosion resistant
  • Tamper resistant
  • Anti-siphon and alternate discharge port
  • Discharge port for 1/4” plastic pipe or 5/8” I.D. hose
  • 1/2” Brass male pipe thread inlet port for positive seal
  • Nominal start to open water temperature of FP-45 is 43F
  • High temperature U.V. stabilized body material
  • Ideal for back-up freeze protection
  • Actual size is 5” high
  • Available in standard and lead-free versions upon request.
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Solar Panels

Inlet Size:



Outlet Size:


Pressure Rating:

125 psi


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