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Product at a glance

Mains operated frost protection electronic room thermostat

The HFT4 is an electronic, mains-operated frost protection thermostat. It ensures heating will switch on whenever frost conditions are detected. This is part of a range of purpose designed room thermostats offering the latest energy saving control technology, combined with established Secure design and manufacturing expertise. This makes them suitable for use in most types of heating system that respond to a 230V mains electrical On/Off signal. Perfect partners for use with our range of programmers and zone valves. Designed to look good, these thermostats will outperform many older styles of thermostat and can often produce savings in the order of 10% over and above those achieved by traditional units using older technology.


  • New installations
  • Replacement of old or inefficient thermostats
  • System upgrades to add a room thermostat
  • Frost protection • Multi occupancy buildings
  • Control of most domestic gas or oil-powered central heating systems
  • Control of additional heating zones
  • Combination (‘combi’) boilers
  • Control of solid-fuel heating systems


  • Easy to install and use
  • Peace of mind that thermostat is tamper-proof
  • Benefits of weather/frost protection
  • Reduce temperature swing that normally occurs with older style thermostats
  • Increased energy savings


  • Wireless or wired (battery operated) versions
  • Load compensation
  • Boiler Plus compliant when used with a time control
  • Clear back-lit digital display
  • Set temperature displayed; actual temperature displayed if the dial is pressed
  • Temperature setting range 0-20°C
  • Industry standard wall plate
  • Internal setting dial
  • Standard fixing centres
  • 7 years no quibbles warranty


Power supply 230V 50Hz
Contact rating 3 (1) Amps 230V AC
Contact type Micro-disconnection
Pollution degree Degree 2
Temperature accuracy +/- 0.5°C (at 21 °C with 0.5 amp load)
Temperature range 0-20°C
Case material Thermoplastic flame retardant
Dimensions 86 x 86 x 36.25mm
Rated impulse voltage Cat 2 – 2500V
Enclosure protection IP30
Design standard EN60730 – 2-9
ERP rating Class IV (2%)

What's in the box

  • HFT4 thermostat
  • Standard 6-pin wall plate
  • User and installation guide
  • ErP Directive Class Declaration sheet