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Product at a glance

The C1727 is a 2-channel smart programmer that can control heat pumps, combi, and system boilers. Out of the box, it is Bluetooth and app enabled and has the option of a plug in Wi-Fi adapter to give complete smart control. The C1727 is designed to supersede the CentaurPlus and ServicePlus range of time switches and programmers by using the same wall plate with minor wiring changes, providing benefits of extra connectivity. The C1727 can easily control a single or double heating zone, or heating and stored hot water system. You can even control the schedule of an existing wired thermostat or add extra sensors to a spare zone to give further control. There is no hub or gateway to configure and power for remote access; simply plug the Wi-Fi card into the front slot, provide the password via the app and you will be connected. The C1727 also includes many of the latest Boiler Plus energy-saving features, such as optimum start and stop per heating zone, as well as on-off load compensation. This significantly improves boiler efficiency by preventing short-cycling and overshooting of temperature and helps to save more energy and improve efficiency.


  • Replacement for CentaurPlus and ServicePlus ranges
  • Combi or system boilers and heat pumps up to 2-zones
  • Central heating and hot water control
  • Control the schedule of existing wired thermostats


  • Uses standard 6-pin backplate for easier retrofits
  • Click-off / Click-on with simple wiring changes for easy and quicker installation
  • 12-year battery life warranty on programmable thermostat display (PTD)
  • No Wi-Fi necessary for local remote control of heating via app using Bluetooth
  • Boiler Plus compliant (load compensation and optimum start/stop)
  • Energy Company Obligation eligible measure


  • 2 channels, 3A rated, volt-free operation
  • Optimum start and stop
  • 6-pin backplate
  • Load compensation for efficiency and comfort
  • Service Interval reminder
  • Installer and user app (Android and iOS)
  • Local control by mobile app using Bluetooth
  • Smart control via optional Wi-Fi adaptor

Technical specifications

Number of channels 2
Relay input voltage rating (CH1 and CH2) 12V to 30V DC, or 230/240V (50Hz)
Relay input/output current rating Voltage-free c/o contacts (SPDT)
Supply (receiver) 230 V/240 V AC (50Hz)
Battery specification (PTD) Non replaceable 2x A lithium ion, 3.6 V, 3600 mAh
Battery life (PTD) ≈12 years
Insulation category CAT II
Software class Class A
Control type Micro-interruption
Design standards Product Standard: EN 60730-1, EN 60730-2-9
RED Radio: ETSI EN 300 328
RED EMC: ETSI EN 301 489-1, ETSI EN 301 489-17
Safety: EN 62311 :2008, EN62368-1 :2014
Dimensions (receiver) 91 x 153 x 32.5mm
Dimensions (PTD) 100 x 100 x 29mm
Weight (receiver) 161g (approx.)
Case material Thermoplastic flame retardant
Mounting 6-pin standard wall plate
Impulse voltage rating Cat II 2500V
Enclosure protection IP30
Pollution degree Degree 2
Operating temperature range 0 °C to +40 °C
Storage temperature -20°C to +70°C
Environmental humidity range 0 to 90%
Compliance Bluetooth BLE compliant
Operating frequency 2.4 GHZ
RF range ~60 m, line of sight