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Scully ST-35 Overfill Prevention Control Unit

Multiple-Point, Optic-Sensing Overfill Prevention Control Unit

  • Interfaces with five-wire optic sensors
  • Used, typically for bottom and top-loading of tank vehicles
  • Mounted at the loading rack/gantry and connects to the vehicle via the Scully plug and cable assembly (sold separately).
  • Features Dynacheck® circuitry for automatic and continuous self-checking of all system components
  • For vehicle ground/earth verification options, consult Scully for information on the Groundhog Self-Proving Grounding System.
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  • Description
  • Brand
  • Additional Information
  • Variants
  • Tech Specs
  • ST-35 models monitor 1 to 8 compartment vehicles. ST-35C models monitor 1- to 12-compartment vehicles.
  • Signals for automatic shut off of product flow within a half-second of detecting a potential overfill condition.
  • Complete compatibility with Scully five-wire optic sensors, IntelliCheck® and Load Anywhere® onboard tank vehicle mounted overfill prevention systems.
  • Will not permit loading under any fault or wet sensor condition.
AYTC is an authorized full service distributor of Scully products. Scully is the market leader in overfill prevention systemsretained product monitoringvehicle groundinglevel alert notification and vehicle to terminal communications.

3/4", 1"


Part Number Model Number Description
7901 ST-35-115-EL Multi-Point Optic Overfill Prevention Control, explosion-proof housing w/ lamps
7903 ST-35-115-ELK Multi-Point Optic Overfill Control, indicator lamps and bypass control (115 VAC)
7931 ST-35-240-ELK Multi-Point Optic Overfill Control, indicator lamps an bypass control (240 VAC)


Part Number Model Number Description
8161 SC-6AO Sculcon® Junction Box Kit, Blue Plug, Blue Coil Cable, 30′
8160 SC-6AO Sculcon Junction Box Kit, Blue Plug, Blue Straight Cable, 20′
8159 SC-6W Sculcon Junction Box Kit, Blue Plug, Blue Coil Cable, 30′
8139 SC-6W Sculcon Junction Box Kit, Blue Plug, Blue Straight Cable, 20′


Part Number Description
8808 Module Assembly- ST-35-115 Multi-Point Optic Controller
7923 Module Assembly- ST-35-240 Multi-Point Optic Controller
Temperature Range: -40° to +140° F (-40° to +60° C)
Weight: 28 lbs. (12.7 kgs.)
Response Time: 0.5 seconds maximum
Approvals: ST-35: FM for use in Class 1, Division 1, Group D hazardous locations
Power Requirements: 100–130 VAC, 50/60 Hz, 20 W max, 200–250 VAC, 50/60 Hz, 20 W max
Connections: Provided by internal terminal strips
Output Relay: One normally open volt-free contact, rated 250 VAC 5A Resistive; energized when the sensors are dry
Output Control Fuse: Internal 5 Ampere
Housing Options: Consult Scully for optional epoxy painted housings for corrosive atmospheres

NOTE: For maximum safety, use only in conjunction with sensors manufactured by Scully to not jeopardize the conditions of these approvals.

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