Since 1988, Multi-Tech Solutions (a division of PumpCon International) has been manufacturing the MOS series protective relay for pump over-temperature and seal fail detection in most all brands of submersible sewage pumps.

  • The plug-in, universal seal failure and over-temperature sensing relay is designed for use with all types of submersible sewage pumps.
  • Separate LED indication as well as relay contact output for each function are included.
  • The MOS Series offers the versatility to protect all submersible sewage pumps with heat sensor and/or seal failure sensing devices installed.
  • The MOS Series may be powered by 24 to 240 VAC, 50/60 Hz with no external or internal modifications.
  • Designs available for monitoring via resistance probes, seal failure float switches, Klixon relays, RTDs and Thermistors. Private labeling is readily available.


The various MOS Series Models can combine detection of circuit combinations for motor and bearing over-temperature and seal failure in a single plug-in unit. In an alert condition, the appropriate LED is illuminated and relay contacts associated with the condition toggle. Thus a load such as the motor contactor may be turned off, or a warning light might be turned on. Upon the occurrence of the first alarm condition, the proper LED will illuminate a steady alarm indication. If the alarm should clear, the LED will then begin to flash, so that the operator will know that at least one alarm occurrence has been detected, and cleared.

A low voltage supply provides power to the over-temperature and seal failure monitoring circuits which control relay outputs based on instructions contained in a microprocessor. The microprocessor circuitry includes power on reset and oscillator start-up timers as well as an independent watchdog timer to insure reliable operation.

A test push button simulates both the over-temperature and seal failure status in the pump seal chamber, and a Reset push button clears the alert indicators after (1) The Test push button has been depressed, or (2) an actual alert has been corrected.

To prevent dislodgment of the module it is designed to be mounted in an industrial type 12 pin socket with hold down clip.


Pump Seal Failure Sensing and Annunciation

  • Resistance Probe, with and without Test Resistor
  • Float Switch; Normally Open or Normally Closed

Stator & Bearing Over-temperature Sensing and Annunciation

  • Klixon
  • RTD
  • Thermistor

Custom Configurations

  • The MOS Series can be custom configured to sense various inputs, such as sensors, etc. If you have a Pump or Motor Protection application not shown here, give us a call!