Qualitrol 121 Direct Mount Thermometer with 4.5″ Dial

Bourdon Tube Thermometer with Flexible Probe

Qualitrol 121 Direct Mount Thermometer with 4.5″ dial (114.3 mm) can be side or top mounted. This bourdon tube thermometer features a swivel probe design that allows for the dial to be angled for more convenient viewing, a reset-able maximum temperature pointer, and up to 3 switches (contacts) for control and alarm functions. Normally installed in an optional well (pocket) that allows units to be replaced or tested without lowering the oil level in the tank or breaking the tank seal.


  • Bourdon tube measurement with reset-able maximum pointer
  • Flexible head for side or top-mount applications
  • Up to 2 fully adjustable switches (contacts) and one additional fixed switch for control and alarm functions
  • 5 inch (130 mm) dial face with an angular dial span of 120° for easy viewing
  • Optimize view of temperature indication with a flexible stem
  • Swivel stem provides up to 70 degrees of angular rotation for convenient viewing
  • Vented case design prevents moisture from accumulating under the lens (sealed versions available)
  • The lens is made of clear, UV stabilized, molded polycarbonate for easy, scratch-resistant viewing throughout the life of the unit
  • Equipped with a 4.5″ (114.3 mm) dial face for clear temperature indication
  • Control and alarm with up to 4 integrated contacts
  • Available with up to 3 switches for alarm, cooling, and/or controlling functions (2 fully adjustable and 1 fixed)
  • Control motors up to 3/4 HP
  • Designed and tested to ensure quality performance
  • A neoprene gasket, integral to the lens and bezel assembly, forms a weather-resistant seal to protect the internal mechanism from the environment
  • Provides accuracy within ±2%
  • Sealed models are rated to NEMA 6, ensuring protection against the weather
  • The magnetically coupled maximum indicating pointer is integral to the polycarbonate lens, providing easy reset without creating a moisture leak path
  • Rugged, epoxy coated, cast-aluminum housing


  • Temperature ranges applicable for oil (liquid) or winding (winding simulation requires heated well or Qualitrol Thermal plate)
  • Up to 3 switches
  • Tank connection style and probe length, compatible well
  • Electrical connection type, connector cable type, and wire colors

Group Created with Sketch. Applications

For temperature indication with integrated control and alarm functions. Designed for use where the point of measurement (the well or pocket) is on the side or top of the apparatus and can be easily viewed.

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