SRT321 is a Z-Wave thermostat that can be integrated with your home control networks to provide ambient temperature sensing and temperature set point functionality. Wireless communications and battery operation make installation quick and simple, by removing the need for disruptive and time consuming wiring.

SRT321 includes load optimisation software that optimises boiler firing to minimise overshooting of temperature in a heated environment. Load optimisation controllers have been shown to provide considerable energy savings, compared with traditional heating controllers.  The interoperable Z-Wave radio enables you to remotely change the set point, read the temperature or receive alerts. SRT323 is an ideal partner for use with a Z-Wave home gateway for web-enabled apps, allowing remote control of heating from anywhere with an Internet connection. You no longer have to worry about returning to a cold house.

By combining ease of use, ease of installation and intelligent control, this thermostat is suitable for use in most heating systems.



  • Control heating within a Z-Wave smart home system

    SRT321 is designed to be used as part of a Z-Wave smart home network, enabling the temperature set point to be controlled via most networks. Through a Z-Wave gateway, the heating can be controlled remotely, via the Internet.

    Domestic gas or oil-fired central heating and hot water systems

    Load optimisation software significantly improves the efficiency of the boiler by preventing short-cycling, while maintaining consistent comfort.

    Combi boiler control

    The single-channel capability of the SRT321 is ideal for controlling a combi boiler via a separate relay, while the load optimisation software ensures the most efficient operation.

    Zone control

    SRT321 is ideal for controlling individual heating zones and is very easy to install. It is battery powered and communicates using mesh radio, so it only needs control wiring. This gives maximum flexibility in choosing the best location to mount the device, and makes it suitable as a direct replacement for existing mechanical (bi-metallic) thermostats.

    New systems

    The flexibility and ease of positioning, due to battery power and wireless communications, make SRT321 ideal for new installations.

  • Key Feature

    • Z-Wave ® mesh radio integration with home control networks
      • No wires
      • Quick and easy to install
      • Compatible with most Z-Wave gateways and receivers
      • Z-Wave Thermostat Device Class using Thermostat Setpoint Command Class
    • Can be directly associated with other Secure Z-Wave relay products
    • Sophisticated load optimisation algorithm
      • Improves energy efficiency
      • Consistent and accurate control, while minimising temperature overshoot
    • Battery operated
    • Uses 2 x AAA cells, with battery life in excess of two years
    • Specification
    • What's in the box
    • Customer testimonials
    • Electrical

      Purpose of control

      Electronic room thermostat RF (independently mounted)


      3 V DC (2 x AAA alkaline batteries)

      Software Class

      Class A


      Mesh radio type


      Operating frequency

      868.42MHz (EU)

      Receiver Category

      Category 3

      Power Class

      Class B

      RF range

      ≈100 m line of sight


      Dimensions (W x H x D)

      86 mm x 86 mm x 36 mm

      Case material

      Flame-retardant thermoplastic

      Ball pressure test temperature



      Industry standard 6-pin wall plate


      Impulse voltage rating

      Cat II 2500V

      Enclosure protection


      Pollution degree

      Degree 2

      Operating temperature range

      0 ˚C to +40 ˚C


      Design standards

      EN 60730-2-9


      ETSI EN 300 220-2

      ETSI EN 301 489-3

      • SRT321 thermostat
      • Standard 6-pin wall plate
      • User and installation manual
      • 2 x AAA batteries (long life) 
    • Vesternet - Colin November 28, 2013

      WORKING WELL WITH INDIGO 6 - After some help, I now have this working well with Indigo 6 and the Secure 2 channel boiler receiver

      Vesternet - Martin Wojcik November 28, 2013

      NICE AND EASY.. - However... I had to enter Installation mode twice on the unit. First time when device has been paired with Vera and second time when Vera could not communicate with the thermostat. After adding thermostat to Vera controller I could see the device in "DEVICES" section but none of the setting was available. Device field/icon displayed 'Waiting to Wakeup to Configure'. In this moment I had to go to the setup again, dial to "n" and allow Vera to configure the unit. Since then everything is spot on... Good stuff and working well...