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Original price $134.62 - Original price $134.62
Original price
$134.62 - $134.62
Current price $134.62

K3.1 flow actuated unloader, 3.0-4.2 GPM 400-1450 psi.


The unloader valve diverts water flow into bypass when the trigger gun valve is closed. Flow actuated unloaders divert water to the bypass when there is a sufficient reduction or stoppage of water flow. The flow actuated unloader has an orifice instead of a check valve in pressure actuate unloaders. When the gun valve is closed and water flow stopes, system pressure is increased rapidly al all points past the orifice. A small channel in front of the orifice allows the increased pressure to travel up to the piston assembly, pushing it down. The rest of the water flow is diverted through the bypass and back to the float tank or pump inlet. 




  • Features all stainless and brass internal parts. 
  • No external moving parts or springs 
  • Unique balance nozzle principle eliminates high pressure in all lines while unit is in bypass mode. 
  • Eliminates pressure peaks normally generated by conventionally designed unloaders. 
  • Unique balanced piston design permits precise pressure adjustment. 
  • Mounts in discharge line: flow through design 
  • Convenient bypass location 
  • Minimum 5% bypass required for operation. 
  • Dual gauge ports 




  • Pressure rating: 2.9 to 4.2 GPM 
  • Discharge pressure: 0 to 1450 psi. 
  • Maximum temperature: 165 f 
  • Inlet port: 3/8" FPT 
  • Outlet port: 3/8" MPT 
  • Bypass port: 3/4" MPT 
  • Dimensions: 5.75" x 3.50" x 2.75" 
  • Weight: 1.7 lbs. 
  • Repair kit: Kit 59 #3146

SU: 1594


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