About Us About Us | Staff


  • We opened our doors in 1946.
  • We have been in business over 60 years.
  • We are a family owned and operated Australian manufacturer.
  • We originally were named Derwent Plastics
  • We originally manufactured Mixmaster mixing bowls and equipment
  • In the 1970’s we were asked to develop an Overload cut out switch
  • In the 1980’s we began R&D on Thermostat switches
  • We are the only Australian owned & operated thermostat manufacturer
  • We supply customers all around the globe.
  • Derwent Thermostats was purchased by FleetTek Engineering Solutions Pty Ltd in December 2012, following the sad passing of its Managing Director, Mr Anthony Siladi.

  • After originally supplying only one overload, Derwent now supplies a range of thermostat and overload switches.
  • We supply both single pole and double pole thermal cut out switches.
  • We provide protection for heating appliances, mains pressure, and instant hot water systems & air conditioning heater banks.
  • We supply some of the largest and most well known Australian companies
  • Our products work in many of the Supermarket freezers that keep Australia’s produce cool.
  • Our products work in many residential hot water systems in Australia.
  • Our products regulate the temperature in many commercial hot water heaters in kitchens around the country.


  • Our Thermostats are part of recently released instant hot water systems for residential use.
  • We are building thermostats and overloads to customer designs.
  • We are building smaller switches to accommodate smaller spaces.
  • We are gaining European certification to enable European sales.
  • We are part of new heating products being exported around the globe.
  • We continue to be the only Australian manufacturers of thermostats and overload cut out switches.

FleetTek Engineering Solutions Pty Ltd - Unit 9/10 Bradford Street, ALEXANDRIA NSW 2015 derwent@fleettek.com.au Ph: 61 2 9693 2666; Fax: 61 2 9693 2662

website design iimage