Saturday, February 12, 2011

Fenwal Temperature Control

Electromechanical Temperature Controls

Fenwal controls manufactures mechanical temperature control devices. The switches are bi-metal switches that use expansion and contraction to cause the switching. This type of mechanism can be extremely accurate but lacks in displaying the temperature. In todays computerized/automated world this type of control tends to be used for over temperature control or alarm as opposed to the process control point.
The FENWAL THERMOSWITCH was invented in the 1930's to control fish tanks, irons and other simple applications, but it was soon realied that they could be used for industrial, commercial and process applications. They're durability, reliability and accuracy are the strong points for THERMOSWITCHES.

THERMOSWITCH® Temperature Controllers are tubular devices featuring an outer shell made of high-expanding metal and internal struts made of low-expanding metal, with a pair of electrical contacts between them.
When the temperature of the media being measured changes, a corresponding change in the spacing of the contacts provides instant on/of
f control with a small differential, resulting in +1°F precision, depending upon the application.

Series 17000, 18000


Series Features:

  • Fast Response - outer shell is the active sensing member
  • Precise Control - substantially reduces overshoot & undershoot
  • Extreme Sensitivity - slow make and break contacts, resolution 0.1°F (0.05°C)
  • Vibration Resistance - best possible control under difficult physical conditions
  • Cost-effective, Compact, Simple-In-Operation
  • Numerous Mounting Configurations
  • Specifications:

  • Overlapping ranges from -100°F to 600°F (-73° to 316°C)
  • 1200 Watt resistive load at 120/240 VAC
  • 5/8" diameter THERMOSWITCH® models available
  • Agency Approvals:

  • UL and CSA


  • Food service equipment
  • Packaging equipment
  • Laminating presses
  • Agricultural equipment

    Fenwal's snap action liquid filled THERMOSWITCH® controllers, the expandable liquid surrounding the bellows is in direct contact with the temperature sensing outer shell providing a fast response for accurate temperature sensing.  The 20000 series switches are no longer available.  Sords Electric has a few left, email us with a part number.

    Series 20000, 21000, 22000

    Fenwal Thermoswitch 20000


    Series Features:

  • Individually field adjustable micro-switches
  • One or two micro-switches
  • Specifications:

  • Overlapping ranges from 0° to 300°F (-18° to 148°C)
  • Ratings to 15 A at 120/250 VAC
  • Factory preset temperatures available
  • NEMA 4 enclosure available

  • Agency Approvals:

  • UL, CSA


  • Food service equipment
  • Medical vaporizers
  • Commercial dishwashers

    Based on the differential expansion of metals principle, an increase in temperature causes the stainless steel outer case of the Surface Mounting THERMOSWITCH® controller to expand at a greater rate than the internal bridge assembly.
    Because the case is in direct contact with the heated surface, a temperature change is sensed almost instantaneously.

    Series 30000

    Fenwal Thermoswitch 30000


    Series Features:

  • Fully adjustable
  • Narrow temperature differential
  • Compact size
  • Economical
  • Factory preset temperatures
  • NEMA 4 enclosure

  • Specifications:

  • Overlapping ranges from 50° to 600°F (10° to 315°C)
  • 1200 Watt resistive load at 120/240 VAC
  • Minimum contact rating of 100,000 cycle
  • Options:

  • Cross mounting bracket
  • Slotted and extended adjusting screw lengths
  • Factory preset temperature
  • Special range calibration
  • Agency Approvals:

  • UL


  • Plastic laminating presses
  • Food warming trays
  • Popcorn machines
  • Domestic appliances
  • Industrial steam cleaners

  • Sords Electric and Control