SRT323 is a single-box solution with integrated relay that includes load compensation software and interoperable Z-Wave radio.

It can be used as a direct replacement for existing thermostats, without the need for wiring changes, while the load compensation software optimises boiler firing to help maintain the set temperature without 'overshooting'. Load compensation 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.

Note: this thermostat has a built-in relay, and is therefore not intended to directly associate with a Z-Wave relay via mesh radio. For such applications, our SRT321 should be used. This provides the same functionality, but without a relay, allowing it to be directly associated with a receiver.



  • Control heating in a Z-Wave smart home system

    SRT323 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

    Its integrated 3-ampere relay makes SRT323 ideal for controlling gas or oil-fired central heating systems. load compensation software significantly improves the efficiency of the boiler by preventing short-cycling, while maintaining consistent comfort.

    Combi boiler control

    The single-channel relay incorporated within the SRT323 enables it to control a combi boiler directly, while the load compensation software ensures the most efficient operation. It requires only minimal wiring between the boiler and the relay.

    Zone control

    SRT323 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 SRT323 ideal for new installations.

    Replacement of conventional room thermostats

    SRT323 fits on to the industry standard 6-pin wall plate, so it can be fitted as a drop-in replacement for most other existing thermostats. 

  • 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
    • Integrated relay
      • No need for an external receiver
    • Sophisticated load compensation 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
    • Customer testimonials
    • Electrical

      Purpose of control

      Electronic room thermostat +RF (independently mounted)

      Contact rating

      3 (1) A, 230 V AC

      Contact type



      3 V DC (2 x AAA alkaline batteries)


      Action Type 1B

      Operating time limitation


      Software Class

      Class A


      Mesh radio type


      Operating frequency

      868.42 MHz (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

      75 °C


      Industry standard 6-pin wall plate

      Environmental 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

      What's in the box

      • SRT323 thermostat
      • 2 x AAA batteries (long life)
      • Standard 6-pin wall plate
      • User and installation instructions
      • ErP Directive Class Declaration Sheet



    • Vesternet – James Notts June 9, 2016

      “Have been using this thermostat with Fibaro HC2 for around 4 months now and so far no problems at all. Very easy to install as direct replacement for Honeywell CM927 battery powered thermostat. Included in network and created three devices - thermostat for setting the set point, temperature sensor and current status (heating or off). Connected to two wires to boiler for dry contact on/off and battery is still strong even with 5 minute wake up intervals to fetch remote temperature settings.

      Will be buying another for second heating zone.