These heavy-duty, flanged, gas-powered, 2-step suction stop valves are designed to control the flow of refrigerant in large industrial and commercial refrigeration systems.
They remain normally open via a spring and require no pressure drop to operate. A single pilot solenoid valve is required to control a higher pressure refrigerant gas which closes these valves during defrosting.
The HCK5D valve has an internal, controlled bleed-down (equalize) feature which will not allow the main seat to open until the pressure across the valve is at a lower, safer pressure differential. This eliminates the need for a separate bleed-down solenoid valve, greatly simplifying piping and reducing installed costs.
If a loss of power occurs during defrost, evaporator pressure is utilized to keep the main valve seat closed until bleed-down is complete.