Dwyer | Mercoid | WE Anderson | Flotect

Dwyer Model LDT

Model LDT Leak/Over Temperature Detection Relay

Shaft Seal Leak and Stator Temperature Monitor

Model LDTThe Dwyer Model LDT is used to monitor the shaft seal and the stator temperature of a submersible pump to detect a leak or over temperature before pump failure. A leak is detected by sensing the status of a float or conductivity switch installed in the seal cavity. When this resistance drops below the set sensitivity, the output relay energizes and the LED indicator illuminates. When the seal failure condition clears, the relay automatically resets. A normally closed temperature switch mounted on the stator detects over temperature. The temperature safety feature incorporates a bistable relay that retains its position during power loss and latches on until the remote reset button is pressed. The LDT has adjustable leak sensitivity from 1k to 35k ohm. Installation is made simple with a surface mount configuration.


Dwyer Model LDT Specifications

  • Power Requirement:120 VAC, 50/60 Hz.
  • Power Consumption:4 VA (approximate).
  • Sensitivity: 1k to 35k ohm adjustable.
  • Temperature Limits:Operating: -4 to 131°F (-20 to 55°C); Storage: -40 to 185°F (-40 to 85°C).
  • Sensor Voltage:12 VDC.
  • Switch Type:(2) SPDT.
  • Electrical Rating:10 A @ 120 VAC resistive.
  • Response Times:Leakage Trip: 1 s; Leakage Reset: 1 s; Temperature Trip: 0.1 s.
  • Indicators:Green LED illuminates under normal operation. Red LED’s illuminate when leak or over-temperature is detected.
  • Enclosure: Polycarbonate dust cover.
  • Mounting:Surface mount.
  • Weight:17 oz (482 g).
  • Agency Approval: cUL, UL.


Available Models

  • Model LDT-AS Leak/over temperature detection relay.