Macromatic SFP120C100: Seal Leak, Dual Channel, 120VAC, 4.7-100K Ohms, (2) SPNO 5 Amps


  • Sensitivity Range: 4.7K – 100K Ohms
  • 120V AC
  • (2) 5A SPNO


SF Series Pump Seal Failure Relays are designed to monitor the shaft seals of submersible pumps. A resistive-measuring probe is installed in the pump seal cavity. With input voltage applied, the LED is Green ON. If the seal starts to leak, contaminating fluid enters the seal cavity, which lowers the resistance between the internal probe & the common connection. When the resistance drops below the user-adjustable sensitivity set-point of the relay, the output relay energizes & the LED turns Red ON. The relay output can be used to give an alarm indication of a leaking seal. These products will automatically reset when the fault condition clears. Probes are pulsed with a DC voltage to prevent electroplating.

Seal Leakage Catalog

Application Information:

  • Voltage Tolerance: AC Operation: +10/-15% of nominal at 50/60 Hz.
  • Load (Burden): 3 VA
  • Indicator LEDs: Green ON with input voltage applied; Red ON when seal leak detected & relay is energized.
  • Probe Voltage: 5V DC Pulsed
  • Response Time: Pick-up & Drop-out: 1 Second
  • Output Contacts: (2) 5A @ 240V AC/28V DC, 1/4HP @ 120V AC (N.O.)
  • Life: Mechanical: 10,000,000 operations; Full Load: 100,000 operations
  • Temperature: -28o to 65o C (-18o to 149o F)


Function Chart: