Welcome to MDI Inc.

At Mercury Displacement Industries we manufacture the Liquid Level Control Float Switch in Wide and Narrow angle mechanical or mercury type. A wide variety of High Temperature float switches, Twin & Vertical Float switches, and cord sets available. We supply OEM's, Plumbing Supply companies, Contractors, Municipal Sewage Treatment plants, and Control Panel Specialists. We also manufacture Mercury Contactors, Relays, Tilt Switches, Solid State Relays and Timers. We now sell a variety of Grinder Pumps & Sewage Pumps.
Please call us at (800) 634-4077 / (269) 663-8574, Fax (269) 663-2924 or E-Mail Us.

Come check out our new Catalog Z!

SSL Certificate
M D I, Controls, Control Sys & Regulators, Edwardsburg, MI

Mercury Relays or Contactors, SSRs, Timers or Tilt Switches

  • Mercury Relays ratings up to 100 AMPS
  • 1 through 4 pole configurations
  • Mercury Relays, the best relays for heater loads
  • Coil voltages up to 600 volts
  • Hermetically sealed contacts
  • Suitable for resistive, capacitive and inductive loads
  • Solid State Relays up to 100 AMPS
  • Magnetic (Midi) Relays up to 210 AMPS
  • Various size and AMP (up to 20 AMPS) rated Tilt Switches
  • Many other options available

Mechanical and Mercury Liquid Level Control Float Switches

  • Ratings up to 2 HP or 25 AMP
  • High Impact Polystyrene, ABS or High Temp Polycarbonate ABS (up to 221°F)
  • Any cord length available. UL Max. 99'
  • 120 and 240 VAC series plugs, 3 pin barrel plug, or standard skive available
  • External Weights or Internally Weighted float switches
  • Twin Float Switch (Up to 15 AMPS and 2 HP)
  • Vertical Switch
    • Standard: 13 AMPS @ 1/2 HP
    • With Relay: 15 AMPS & 1 HP @ 120 VAC or 2 HP @ 240 VAC
  • Many other options and Various Colors available